United States Environmental Protection Agency
Degradation Kinetics of Multiwall Carbon Nanotube Reinforced Polypropylene During Environmental AgingChangseok Han1, E. Sahle-Demessie2*, Amy Zhao2, Jun Wang31Oak Ridge Institute for Science and Education, Oak Ridge, TN 37831, U.S.2U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, U.S.3Perkin Elmer, Inc., 710 Bridgeport Avenue, Shelton, CT 06484-4794.*Corresponding author. Tel: +1-513-569-7739. E-mail: Sahle-Demessie.Endalkachew@(Endalkachew Sahle-Demessie) AbstractThe degradation of isotactic polypropylene (PP) and PP-multi-walled carbon nanotube (PP-MWCNT) during environmental weathering resulted in an increased degree of crystallinity, making the materials brittle, and creating spontaneous surface cracks. The degradation resulted eventual breakdown of wafers and increasing the potential for the release of incorporated nano-fillers. Thermal analysis showed wafer’s thickness and reinforcement with MWCNT had a significant influence on the stability of MWCNT-PP composites. Differential scanning calorimetry indicated MWCNTs acted as nucleation points increasing the crystallization temperatures of PP-MWCNT while reducing the extent of aging. Weathering decreased the melting and the crystallization temperatures of PP up to 20 oC where the reduction was inversely proportional to the thickness of the wafers. The activation energy dependencies obtained using isoconversional kinetics of TGA analysis revealed that the effective thermo-oxidative degradations of PP changed during aging. The activation energy for initial stages of thermal degradation decreased from ~330 kJ mol?1 to ～100 kJ mol?1 for pristine aged PP, respectively, where the values increased to ~300 kJ/mol at later degradation stages. The results suggest the kinetics of early degradation was altered due to the change in the molecular structure of aged PP matrix and the shifting in the degradation rate limiting step.Keywords: polypropylene, MWCNT, weathering, activation energy, melting-crystallization points IntroductionThere are a limited number of studies on the aging of different nanocomposites, and the potential release of imbedded filler materials due to environmental aging. Polypropylene (PP) was selected for this study since it is a thermoplastic commonly used for a broad range of applications such as automotive parts, food packaging, housing materials and electrical devices. PP is a semi-crystalline general-purpose polymer that is cheap, mechanically robust, with high resistance to water and chemicals PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5kZSBEaWNhc3RpbGxvPC9BdXRob3I+PFllYXI+MjAxMzwv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ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5kZSBEaWNhc3RpbGxvPC9BdXRob3I+PFllYXI+MjAxMzwv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ADDIN EN.CITE.DATA [1-4]. Nanomaterials have been widely incorporated into polymers to improve the physicochemical properties or provide multi-functions to pristine polymers. Among nanomaterials, multiwall carbon nanotubes (MWCNTs) have been intensively used as an additive to the plastic to make lighter, stronger materials with higher thermal stability, and water resistance PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5DaGVuPC9BdXRob3I+PFllYXI+MjAwNTwvWWVhcj48UmVj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ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5DaGVuPC9BdXRob3I+PFllYXI+MjAwNTwvWWVhcj48UmVj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ADDIN EN.CITE.DATA [5-9]. Because single- or multi-walled carbon nanotubes are approximately the same length as polymer chain-segments, the interaction and mobility result in marked increase in physical and mechanical properties.Although nano-reinforcement improves properties of polymers, the added MWCNTs could be released to the environment as composites age or due to mechanical effects during production, usage phase or at the end of their use. Toxicity of MWCNTs human and animal cells and microorganisms has been reported PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5EdTwvQXV0aG9yPjxZZWFyPjIwMTM8L1llYXI+PFJlY051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ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5EdTwvQXV0aG9yPjxZZWFyPjIwMTM8L1llYXI+PFJlY051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ADDIN EN.CITE.DATA [10-12]. The interaction of released MWCNTs with organic pollutants in the environment can alter the fate and facilitate the transport of hydrophobic organic water contaminants ADDIN EN.CITE <EndNote><Cite><Author>Boddu</Author><Year>2010</Year><RecNum>26</RecNum><DisplayText>[13, 14]</DisplayText><record><rec-number>26</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1470084763">26</key></foreign-keys><ref-type name="Book">6</ref-type><contributors><authors><author>Boddu, Veera</author><author>Redner, Paul</author></authors></contributors><titles><title>Energetic Materials: Thermophysical Properties, Predictions, and Experimental Measurements</title></titles><dates><year>2010</year></dates><publisher>CRC Press</publisher><isbn>1439835144</isbn><urls></urls></record></Cite><Cite><Author>Sahle-Demessie</Author><Year>2016</Year><RecNum>25</RecNum><record><rec-number>25</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1470084714">25</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Sahle-Demessie, E</author><author>Han, Changseok</author><author>Zhao, Amy</author><author>Hahn, Bill</author><author>Grecsek, Heidi</author></authors></contributors><titles><title>Interaction of engineered nanomaterials with hydrophobic organic pollutants</title><secondary-title>Nanotechnology</secondary-title></titles><periodical><full-title>Nanotechnology</full-title></periodical><pages>284003</pages><volume>27</volume><number>28</number><dates><year>2016</year></dates><isbn>0957-4484</isbn><urls></urls></record></Cite></EndNote>[13, 14]. A recent study showed that MWCNTs adsorbed hydrophobic organic contaminants, polyaromatic hydrocarbons (PAHs), and increased the concentration of the PAHs in water phase ADDIN EN.CITE <EndNote><Cite><Author>Sahle-Demessie</Author><Year>2016</Year><RecNum>25</RecNum><DisplayText>[14]</DisplayText><record><rec-number>25</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1470084714">25</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Sahle-Demessie, E</author><author>Han, Changseok</author><author>Zhao, Amy</author><author>Hahn, Bill</author><author>Grecsek, Heidi</author></authors></contributors><titles><title>Interaction of engineered nanomaterials with hydrophobic organic pollutants</title><secondary-title>Nanotechnology</secondary-title></titles><periodical><full-title>Nanotechnology</full-title></periodical><pages>284003</pages><volume>27</volume><number>28</number><dates><year>2016</year></dates><isbn>0957-4484</isbn><urls></urls></record></Cite></EndNote>[14]. The stability and degradation nanocomposites by environmental aging (e.g., photooxidation, chemical oxidation, and mechanical abrasion) is need to understand the release of nanomaterials from polymer nanocomposites better. Environmental aging may alter the structural, physical and chemical properties of the nanocomposite, which are associated with the stability and degradation and potential release of nano-additives. Although long-term tests under natural service conditions are represented real conditions, accelerated aging tests are carried out to establish in a conveniently short time relative ranking of chemical stability or physical durability materials. Accelerated aging tests simulate weather conditions including sunny and rainy day following pre-selected cycles. These tests are used to estimate or “predict” potential long-term serviceability of material, to elucidate the chemical reactions involved the consequences of releasing of nanoparticles. The test could show the overall pattern of deterioration and guide the long-term performance of materials in outdoor conditions and help to assess whether aging releases embedded fillers. To the best of our knowledge, only a limited amount work has been done to systematically explore the effect of environmental aging on thermal properties of MWCNT-polymer composites ADDIN EN.CITE <EndNote><Cite><Author>Ghorbel</Author><Year>1995</Year><RecNum>46</RecNum><DisplayText>[15, 16]</DisplayText><record><rec-number>46</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497288597">46</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Ghorbel, I</author><author>Thominette, F</author><author>Spiteri, P</author><author>Verdu, J</author></authors></contributors><titles><title>Hydrolytic aging of polycarbonate. I. Physical aspects</title><secondary-title>Journal of applied polymer science</secondary-title></titles><periodical><full-title>Journal of Applied Polymer Science</full-title></periodical><pages>163-171</pages><volume>55</volume><number>1</number><dates><year>1995</year></dates><isbn>1097-4628</isbn><urls></urls></record></Cite><Cite><Author>Raghavan</Author><Year>1992</Year><RecNum>45</RecNum><record><rec-number>45</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497288542">45</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Raghavan, D</author><author>Torma, AE</author></authors></contributors><titles><title>DSC and FTIR Characterization of Biodegradation of Polyethylene</title><secondary-title>Polymer Engineering & Science</secondary-title></titles><periodical><full-title>Polymer Engineering & Science</full-title></periodical><pages>438-442</pages><volume>32</volume><number>6</number><dates><year>1992</year></dates><isbn>1548-2634</isbn><urls></urls></record></Cite></EndNote>[15, 16]. Multi-laboratory aging study of polyamide and epoxy-MWCNT composites done using standardized weathering simulation equipment showed the release of MWCNT ADDIN EN.CITE <EndNote><Cite><Author>Wohlleben</Author><Year>2017</Year><RecNum>47</RecNum><DisplayText>[17]</DisplayText><record><rec-number>47</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497288659">47</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Wohlleben, Wendel</author><author>Kingston, Christopher</author><author>Carter, Janet</author><author>Sahle-Demessie, E</author><author>Vázquez-Campos, Socorro</author><author>Acrey, Brad</author><author>Chen, Chia-Ying</author><author>Walton, Ernest</author><author>Egenolf, Heiko</author><author>Müller, Philipp</author></authors></contributors><titles><title>NanoRelease: Pilot interlaboratory comparison of a weathering protocol applied to resilient and labile polymers with and without embedded carbon nanotubes</title><secondary-title>Carbon</secondary-title></titles><periodical><full-title>Carbon</full-title></periodical><pages>346-360</pages><volume>113</volume><dates><year>2017</year></dates><isbn>0008-6223</isbn><urls></urls></record></Cite></EndNote>[17]. However, extended UV-irradiation of epoxy-MWCNT-amin composite showed no detectable release of MWCNT ADDIN EN.CITE <EndNote><Cite><Author>Nguyen</Author><Year>2017</Year><RecNum>48</RecNum><DisplayText>[18]</DisplayText><record><rec-number>48</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497288700">48</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Nguyen, Tinh</author><author>Petersen, Elijah J</author><author>Pellegrin, Bastien</author><author>Gorham, Justin M</author><author>Lam, Thomas</author><author>Zhao, Minhua</author><author>Sung, Lipiin</author></authors></contributors><titles><title>Impact of UV irradiation on multiwall carbon nanotubes in nanocomposites: Formation of entangled surface layer and mechanisms of release resistance</title><secondary-title>Carbon</secondary-title></titles><periodical><full-title>Carbon</full-title></periodical><pages>191-200</pages><volume>116</volume><dates><year>2017</year></dates><isbn>0008-6223</isbn><urls></urls></record></Cite></EndNote>[18].This paper is intended to initiate systematic kinetic studies of the aging of polymer nanocomposites in the understanding of the thermal behavior of these exciting materials as polymer structure changes during environmental weathering. We are reporting the results of a rigorous investigation on the environmental effects using changes in the thermal properties of iPP and PP-MWCNT having different thicknesses before and after aging. The effects of environmental aging on thermal decomposition temperature, the estimated degradation kinetics parameter, activation energy, were investigated. We followed analytical methods used to study degradation of plastics ADDIN EN.CITE <EndNote><Cite><Author>Corrales</Author><Year>2002</Year><RecNum>17</RecNum><DisplayText>[19]</DisplayText><record><rec-number>17</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">17</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Corrales, T</author><author>Catalina, F</author><author>Peinado, C</author><author>Allen, NS</author><author>Fontan, E</author></authors></contributors><titles><title>Photooxidative and thermal degradation of polyethylenes: interrelationship by chemiluminescence, thermal gravimetric analysis and FTIR data</title><secondary-title>Journal of Photochemistry and Photobiology A: Chemistry</secondary-title></titles><pages>213-224</pages><volume>147</volume><number>3</number><dates><year>2002</year></dates><isbn>1010-6030</isbn><urls></urls></record></Cite></EndNote>[19]. Differential scanning calorimetry (DSC) tests were used to examine the changes in other thermal behaviors such as melting and crystallization temperatures ADDIN EN.CITE <EndNote><Cite><Author>Mandelkern</Author><Year>1988</Year><RecNum>18</RecNum><DisplayText>[20, 21]</DisplayText><record><rec-number>18</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">18</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Mandelkern, Leo</author></authors></contributors><titles><title>Characterization of crystalline polymers by Raman spectroscopy and differential scanning calorimetry</title><secondary-title>Polymer characterization: physical property, spectroscopic, and chromatographic methods</secondary-title></titles><pages>377-395</pages><dates><year>1988</year></dates><urls></urls></record></Cite><Cite><Author>Porter</Author><Year>2000</Year><RecNum>19</RecNum><record><rec-number>19</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">19</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Porter, Crystal E</author><author>Blum, Frank D</author></authors></contributors><titles><title>Thermal characterization of PMMA thin films using modulated differential scanning calorimetry</title><secondary-title>Macromolecules</secondary-title></titles><pages>7016-7020</pages><volume>33</volume><number>19</number><dates><year>2000</year></dates><isbn>0024-9297</isbn><urls></urls></record></Cite></EndNote>[20, 21] during the aging process. 2. Experimental2.1 Preparation of Polymer and Polymer-Nanocomposite WafersPolypropylene (Isotactic, average MW ~250,000 and average MN ~67,000) purchased from Sigma-Aldrich. Commercial MWCNTs (NANOCYLTM NC7000, average diameter: 9.5 nm; average length: 1.5 μm) were obtained from the Nanocyl SA (Figure S1). Granular PP was mixed with 4% (w/w) MWCNTs in a heating chamber installed with mechanical mixing rods (Haake Rheocord 90, Thermo Electron Corporation, Waltham, MA). The content of MWCNTs (4 %) was determined based on previous studies reporting that a significant improvement of physicochemical and electrical properties of pristine materials was obtained with a weight fraction of nanofillers less than 5 wt.% in different composites PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5HZW50aWxlPC9BdXRob3I+PFllYXI+MjAxNDwvWWVhcj48
UmVjTnVtPjI4PC9SZWNOdW0+PERpc3BsYXlUZXh0PlsyMi0yNF08L0Rpc3BsYXlUZXh0PjxyZWNv
cmQ+PHJlYy1udW1iZXI+Mjg8L3JlYy1udW1iZXI+PGZvcmVpZ24ta2V5cz48a2V5IGFwcD0iRU4i
IGRiLWlkPSI5MHZkZGV4YTgwd2Y1ZGVwcnY3eHhycmcwMDkyeGFmYWV2c2UiIHRpbWVzdGFtcD0i
MTQ3OTQxMDExMyI+Mjg8L2tleT48L2ZvcmVpZ24ta2V5cz48cmVmLXR5cGUgbmFtZT0iSm91cm5h
bCBBcnRpY2xlIj4xNzwvcmVmLXR5cGU+PGNvbnRyaWJ1dG9ycz48YXV0aG9ycz48YXV0aG9yPkdl
bnRpbGUsIEdlbm5hcm88L2F1dGhvcj48YXV0aG9yPkFtYnJvZ2ksIFZlcm9uaWNhPC9hdXRob3I+
PGF1dGhvcj5DZXJydXRpLCBQaWVyZnJhbmNlc2NvPC9hdXRob3I+PGF1dGhvcj5EaSBNYWlvLCBS
b3NhPC9hdXRob3I+PGF1dGhvcj5OYXN0aSwgR2l1c2VwcGU8L2F1dGhvcj48YXV0aG9yPkNhcmZh
Z25hLCBDb3NpbW88L2F1dGhvcj48L2F1dGhvcnM+PC9jb250cmlidXRvcnM+PHRpdGxlcz48dGl0
bGU+UHJvcyBhbmQgY29ucyBvZiBtZWx0IGFubmVhbGluZyBvbiB0aGUgcHJvcGVydGllcyBvZiBN
V0NOVC9wb2x5cHJvcHlsZW5lIGNvbXBvc2l0ZXM8L3RpdGxlPjxzZWNvbmRhcnktdGl0bGU+UG9s
eW1lciBEZWdyYWRhdGlvbiBhbmQgU3RhYmlsaXR5PC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+
PHBlcmlvZGljYWw+PGZ1bGwtdGl0bGU+UG9seW1lciBEZWdyYWRhdGlvbiBhbmQgU3RhYmlsaXR5
PC9mdWxsLXRpdGxlPjwvcGVyaW9kaWNhbD48cGFnZXM+NTYtNjQ8L3BhZ2VzPjx2b2x1bWU+MTEw
PC92b2x1bWU+PGRhdGVzPjx5ZWFyPjIwMTQ8L3llYXI+PC9kYXRlcz48aXNibj4wMTQxLTM5MTA8
L2lzYm4+PHVybHM+PC91cmxzPjwvcmVjb3JkPjwvQ2l0ZT48Q2l0ZT48QXV0aG9yPkthc2hpd2Fn
aTwvQXV0aG9yPjxZZWFyPjIwMDQ8L1llYXI+PFJlY051bT4yOTwvUmVjTnVtPjxyZWNvcmQ+PHJl
Yy1udW1iZXI+Mjk8L3JlYy1udW1iZXI+PGZvcmVpZ24ta2V5cz48a2V5IGFwcD0iRU4iIGRiLWlk
PSI5MHZkZGV4YTgwd2Y1ZGVwcnY3eHhycmcwMDkyeGFmYWV2c2UiIHRpbWVzdGFtcD0iMTQ3OTQx
NjY0NiI+Mjk8L2tleT48L2ZvcmVpZ24ta2V5cz48cmVmLXR5cGUgbmFtZT0iSm91cm5hbCBBcnRp
Y2xlIj4xNzwvcmVmLXR5cGU+PGNvbnRyaWJ1dG9ycz48YXV0aG9ycz48YXV0aG9yPkthc2hpd2Fn
aSwgVGFrYXNoaTwvYXV0aG9yPjxhdXRob3I+R3J1bGtlLCBFcmljPC9hdXRob3I+PGF1dGhvcj5I
aWxkaW5nLCBKZW5ueTwvYXV0aG9yPjxhdXRob3I+R3JvdGgsIEthdHJpbmE8L2F1dGhvcj48YXV0
aG9yPkhhcnJpcywgUmljaGFyZDwvYXV0aG9yPjxhdXRob3I+QnV0bGVyLCBLYXRocnluPC9hdXRo
b3I+PGF1dGhvcj5TaGllbGRzLCBKb2huPC9hdXRob3I+PGF1dGhvcj5LaGFyY2hlbmtvLCBTZW1l
bjwvYXV0aG9yPjxhdXRob3I+RG91Z2xhcywgSmFjazwvYXV0aG9yPjwvYXV0aG9ycz48L2NvbnRy
aWJ1dG9ycz48dGl0bGVzPjx0aXRsZT5UaGVybWFsIGFuZCBmbGFtbWFiaWxpdHkgcHJvcGVydGll
cyBvZiBwb2x5cHJvcHlsZW5lL2NhcmJvbiBuYW5vdHViZSBuYW5vY29tcG9zaXRlczwvdGl0bGU+
PHNlY29uZGFyeS10aXRsZT5Qb2x5bWVyPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBlcmlv
ZGljYWw+PGZ1bGwtdGl0bGU+UG9seW1lcjwvZnVsbC10aXRsZT48L3BlcmlvZGljYWw+PHBhZ2Vz
PjQyMjctNDIzOTwvcGFnZXM+PHZvbHVtZT40NTwvdm9sdW1lPjxudW1iZXI+MTI8L251bWJlcj48
ZGF0ZXM+PHllYXI+MjAwNDwveWVhcj48L2RhdGVzPjxpc2JuPjAwMzItMzg2MTwvaXNibj48dXJs
cz48L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjxDaXRlPjxBdXRob3I+V2luZXk8L0F1dGhvcj48WWVh
cj4yMDA3PC9ZZWFyPjxSZWNOdW0+MzA8L1JlY051bT48cmVjb3JkPjxyZWMtbnVtYmVyPjMwPC9y
ZWMtbnVtYmVyPjxmb3JlaWduLWtleXM+PGtleSBhcHA9IkVOIiBkYi1pZD0iOTB2ZGRleGE4MHdm
NWRlcHJ2N3h4cnJnMDA5MnhhZmFldnNlIiB0aW1lc3RhbXA9IjE0Nzk0MTY5MTciPjMwPC9rZXk+
PC9mb3JlaWduLWtleXM+PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10
eXBlPjxjb250cmlidXRvcnM+PGF1dGhvcnM+PGF1dGhvcj5XaW5leSwgS2FyZW4gSTwvYXV0aG9y
PjxhdXRob3I+VmFpYSwgUmljaGFyZCBBPC9hdXRob3I+PC9hdXRob3JzPjwvY29udHJpYnV0b3Jz
Pjx0aXRsZXM+PHRpdGxlPlBvbHltZXIgbmFub2NvbXBvc2l0ZXM8L3RpdGxlPjxzZWNvbmRhcnkt
dGl0bGU+TVJTIGJ1bGxldGluPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBlcmlvZGljYWw+
PGZ1bGwtdGl0bGU+TVJTIGJ1bGxldGluPC9mdWxsLXRpdGxlPjwvcGVyaW9kaWNhbD48cGFnZXM+
MzE0LTMyMjwvcGFnZXM+PHZvbHVtZT4zMjwvdm9sdW1lPjxudW1iZXI+MDQ8L251bWJlcj48ZGF0
ZXM+PHllYXI+MjAwNzwveWVhcj48L2RhdGVzPjxpc2JuPjE5MzgtMTQyNTwvaXNibj48dXJscz48
L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjwvRW5kTm90ZT4A
ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5HZW50aWxlPC9BdXRob3I+PFllYXI+MjAxNDwvWWVhcj48
UmVjTnVtPjI4PC9SZWNOdW0+PERpc3BsYXlUZXh0PlsyMi0yNF08L0Rpc3BsYXlUZXh0PjxyZWNv
cmQ+PHJlYy1udW1iZXI+Mjg8L3JlYy1udW1iZXI+PGZvcmVpZ24ta2V5cz48a2V5IGFwcD0iRU4i
IGRiLWlkPSI5MHZkZGV4YTgwd2Y1ZGVwcnY3eHhycmcwMDkyeGFmYWV2c2UiIHRpbWVzdGFtcD0i
MTQ3OTQxMDExMyI+Mjg8L2tleT48L2ZvcmVpZ24ta2V5cz48cmVmLXR5cGUgbmFtZT0iSm91cm5h
bCBBcnRpY2xlIj4xNzwvcmVmLXR5cGU+PGNvbnRyaWJ1dG9ycz48YXV0aG9ycz48YXV0aG9yPkdl
bnRpbGUsIEdlbm5hcm88L2F1dGhvcj48YXV0aG9yPkFtYnJvZ2ksIFZlcm9uaWNhPC9hdXRob3I+
PGF1dGhvcj5DZXJydXRpLCBQaWVyZnJhbmNlc2NvPC9hdXRob3I+PGF1dGhvcj5EaSBNYWlvLCBS
b3NhPC9hdXRob3I+PGF1dGhvcj5OYXN0aSwgR2l1c2VwcGU8L2F1dGhvcj48YXV0aG9yPkNhcmZh
Z25hLCBDb3NpbW88L2F1dGhvcj48L2F1dGhvcnM+PC9jb250cmlidXRvcnM+PHRpdGxlcz48dGl0
bGU+UHJvcyBhbmQgY29ucyBvZiBtZWx0IGFubmVhbGluZyBvbiB0aGUgcHJvcGVydGllcyBvZiBN
V0NOVC9wb2x5cHJvcHlsZW5lIGNvbXBvc2l0ZXM8L3RpdGxlPjxzZWNvbmRhcnktdGl0bGU+UG9s
eW1lciBEZWdyYWRhdGlvbiBhbmQgU3RhYmlsaXR5PC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+
PHBlcmlvZGljYWw+PGZ1bGwtdGl0bGU+UG9seW1lciBEZWdyYWRhdGlvbiBhbmQgU3RhYmlsaXR5
PC9mdWxsLXRpdGxlPjwvcGVyaW9kaWNhbD48cGFnZXM+NTYtNjQ8L3BhZ2VzPjx2b2x1bWU+MTEw
PC92b2x1bWU+PGRhdGVzPjx5ZWFyPjIwMTQ8L3llYXI+PC9kYXRlcz48aXNibj4wMTQxLTM5MTA8
L2lzYm4+PHVybHM+PC91cmxzPjwvcmVjb3JkPjwvQ2l0ZT48Q2l0ZT48QXV0aG9yPkthc2hpd2Fn
aTwvQXV0aG9yPjxZZWFyPjIwMDQ8L1llYXI+PFJlY051bT4yOTwvUmVjTnVtPjxyZWNvcmQ+PHJl
Yy1udW1iZXI+Mjk8L3JlYy1udW1iZXI+PGZvcmVpZ24ta2V5cz48a2V5IGFwcD0iRU4iIGRiLWlk
PSI5MHZkZGV4YTgwd2Y1ZGVwcnY3eHhycmcwMDkyeGFmYWV2c2UiIHRpbWVzdGFtcD0iMTQ3OTQx
NjY0NiI+Mjk8L2tleT48L2ZvcmVpZ24ta2V5cz48cmVmLXR5cGUgbmFtZT0iSm91cm5hbCBBcnRp
Y2xlIj4xNzwvcmVmLXR5cGU+PGNvbnRyaWJ1dG9ycz48YXV0aG9ycz48YXV0aG9yPkthc2hpd2Fn
aSwgVGFrYXNoaTwvYXV0aG9yPjxhdXRob3I+R3J1bGtlLCBFcmljPC9hdXRob3I+PGF1dGhvcj5I
aWxkaW5nLCBKZW5ueTwvYXV0aG9yPjxhdXRob3I+R3JvdGgsIEthdHJpbmE8L2F1dGhvcj48YXV0
aG9yPkhhcnJpcywgUmljaGFyZDwvYXV0aG9yPjxhdXRob3I+QnV0bGVyLCBLYXRocnluPC9hdXRo
b3I+PGF1dGhvcj5TaGllbGRzLCBKb2huPC9hdXRob3I+PGF1dGhvcj5LaGFyY2hlbmtvLCBTZW1l
bjwvYXV0aG9yPjxhdXRob3I+RG91Z2xhcywgSmFjazwvYXV0aG9yPjwvYXV0aG9ycz48L2NvbnRy
aWJ1dG9ycz48dGl0bGVzPjx0aXRsZT5UaGVybWFsIGFuZCBmbGFtbWFiaWxpdHkgcHJvcGVydGll
cyBvZiBwb2x5cHJvcHlsZW5lL2NhcmJvbiBuYW5vdHViZSBuYW5vY29tcG9zaXRlczwvdGl0bGU+
PHNlY29uZGFyeS10aXRsZT5Qb2x5bWVyPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBlcmlv
ZGljYWw+PGZ1bGwtdGl0bGU+UG9seW1lcjwvZnVsbC10aXRsZT48L3BlcmlvZGljYWw+PHBhZ2Vz
PjQyMjctNDIzOTwvcGFnZXM+PHZvbHVtZT40NTwvdm9sdW1lPjxudW1iZXI+MTI8L251bWJlcj48
ZGF0ZXM+PHllYXI+MjAwNDwveWVhcj48L2RhdGVzPjxpc2JuPjAwMzItMzg2MTwvaXNibj48dXJs
cz48L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjxDaXRlPjxBdXRob3I+V2luZXk8L0F1dGhvcj48WWVh
cj4yMDA3PC9ZZWFyPjxSZWNOdW0+MzA8L1JlY051bT48cmVjb3JkPjxyZWMtbnVtYmVyPjMwPC9y
ZWMtbnVtYmVyPjxmb3JlaWduLWtleXM+PGtleSBhcHA9IkVOIiBkYi1pZD0iOTB2ZGRleGE4MHdm
NWRlcHJ2N3h4cnJnMDA5MnhhZmFldnNlIiB0aW1lc3RhbXA9IjE0Nzk0MTY5MTciPjMwPC9rZXk+
PC9mb3JlaWduLWtleXM+PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10
eXBlPjxjb250cmlidXRvcnM+PGF1dGhvcnM+PGF1dGhvcj5XaW5leSwgS2FyZW4gSTwvYXV0aG9y
PjxhdXRob3I+VmFpYSwgUmljaGFyZCBBPC9hdXRob3I+PC9hdXRob3JzPjwvY29udHJpYnV0b3Jz
Pjx0aXRsZXM+PHRpdGxlPlBvbHltZXIgbmFub2NvbXBvc2l0ZXM8L3RpdGxlPjxzZWNvbmRhcnkt
dGl0bGU+TVJTIGJ1bGxldGluPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBlcmlvZGljYWw+
PGZ1bGwtdGl0bGU+TVJTIGJ1bGxldGluPC9mdWxsLXRpdGxlPjwvcGVyaW9kaWNhbD48cGFnZXM+
MzE0LTMyMjwvcGFnZXM+PHZvbHVtZT4zMjwvdm9sdW1lPjxudW1iZXI+MDQ8L251bWJlcj48ZGF0
ZXM+PHllYXI+MjAwNzwveWVhcj48L2RhdGVzPjxpc2JuPjE5MzgtMTQyNTwvaXNibj48dXJscz48
L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjwvRW5kTm90ZT4A
ADDIN EN.CITE.DATA [22-24]. The mixture of PP and MWCNT was kept above a melting temperature of isotactic PP (165 oC). While melting PP, the mixture was kept mixing for 30-60 min to achieve uniformly distribute MWCNTs in PP. The mixed materials were transferred to an extruder (Rheomex 102, USA), which was adjusted to control the thickness of polymer sheet roles. The wafers of PP and PP-MWCNT composites with three different thicknesses were prepared using the extruder. The prepared samples were denoted based on the composition of MWCNTs and wafer thickness (Table 1). Scheme 1 (Supplementary Section) shows simplified procedures for the wafer preparation of PP and PP-MWCNT nanocomposite. As seen in Figure 1, MWCNTs were well dispersed in PP-MWCNT nanocomposite. The prepared wafers were used for all aging experiment to investigate changes in their thermal stability and property during or at the end of the aging process.2.2 Aging of PP and PP-MWCNT nanocompositeThe effect of weather and climate on the properties of PP and PP-MWCNT were studied by using accelerated environmental aging chamber (Suntest XLS+, Atlas Material Testing Technology LLC). Samples of PP and PP-MWCNT composite with a width of 5 cm and a length of 5 cm were placed on a stainless mesh plate. The method used for this study follows ISO-4892-2/2013 method for accelerated aging ADDIN EN.CITE <EndNote><Cite><Author>Wohlleben</Author><Year>2017</Year><RecNum>47</RecNum><DisplayText>[17, 25]</DisplayText><record><rec-number>47</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497288659">47</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Wohlleben, Wendel</author><author>Kingston, Christopher</author><author>Carter, Janet</author><author>Sahle-Demessie, E</author><author>Vázquez-Campos, Socorro</author><author>Acrey, Brad</author><author>Chen, Chia-Ying</author><author>Walton, Ernest</author><author>Egenolf, Heiko</author><author>Müller, Philipp</author></authors></contributors><titles><title>NanoRelease: Pilot interlaboratory comparison of a weathering protocol applied to resilient and labile polymers with and without embedded carbon nanotubes</title><secondary-title>Carbon</secondary-title></titles><periodical><full-title>Carbon</full-title></periodical><pages>346-360</pages><volume>113</volume><dates><year>2017</year></dates><isbn>0008-6223</isbn><urls></urls></record></Cite><Cite><Author>Wohlleben</Author><Year>2016</Year><RecNum>49</RecNum><record><rec-number>49</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497288897">49</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Wohlleben, Wendel</author><author>Neubauer, Nicole</author></authors></contributors><titles><title>Quantitative rates of release from weathered nanocomposites are determined across 5 orders of magnitude by the matrix, modulated by the embedded nanomaterial</title><secondary-title>NanoImpact</secondary-title></titles><periodical><full-title>NanoImpact</full-title></periodical><pages>39-45</pages><volume>1</volume><dates><year>2016</year></dates><isbn>2452-0748</isbn><urls></urls></record></Cite></EndNote>[17, 25]. The plate was put in the accelerating solar aging system (Figure S2). Experimental conditions for the solar aging of samples are provided in Table 2. A cycle of weathering repeated during total experiment duration (3024 h (18 weeks)). Samples of PP and PP-MWCNT composite were taken at 0, 756, 1512, 2268, and 3024 h and total solar irradiant of each sampling time was recorded and converted to real exposure times using annual solar radiant exposure data in subtropical regions (i.e., Florida, USA (6588 MJ/m2)) ADDIN EN.CITE <EndNote><Cite><Author>AMETEK?</Author><Year>Retrived February 23, 2017</Year><RecNum>32</RecNum><DisplayText>[26]</DisplayText><record><rec-number>32</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1487864783">32</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>AMETEK?</author></authors></contributors><titles><title>Benchmark Climates</title><secondary-title> February 23, 2017</year></dates><urls><related-urls><url>;[26]. The converted real exposure time during the aging experiment was summarized in Table 3.2.3 Characterizing Environmentally Aged PP-MWCNT CompositesDifferential scanning calorimetric (DSC) is a thermal analysis technique used to study thermal behaviors of different materials such as melting and crystallization temperatures, enthalpy of melting and crystallization temperatures. DSC was used for detecting the chemical and morphological changes that accompany aging and degradation. Three to four milligrams of the samples were placed in a platinum subjected to controlled temperature variation. The sample pan and an empty reference pan were positioned in the DSC4 pan (TA, DSC Q2000, New Castle, DA) and heated simultaneously to 200 oC at 10 oC/min. The temperatures of the two pans were monitored and the rate of heat flowing to the samples adjusted to keep the temperatures of the two samples equals. The melting (Tm) and crystallization (Tc) temperatures the pristine, and MWCNT reinforced PP before and after aging. The replicate run of each sample was averaged to calculate heat flow at a given temperature (standard deviation 0.6 mcal/sec/g).TGA (Pyrus 7, Perkin Elmer Inc.) was used to investigate changes in thermal stability due to MWCNT reinforcement of PP, environmental aging, and wafer thickness. The analytical conditions for TGA and DSC are summarized in Table 4. TGA is based on measuring the temperature dependence of the loss of sample weight due to the formation of volatile products. The initial sample was kept as constant for all sample at 3.090 ± 0.135 mg, to minimize variation in the analysis. The rate of the thermal decomposition of materials depends on the temperature the of the samples and the rate of heating, that is the time the sample spends at a given temperature. Thus, the thermal decomposition kinetics of the TGA data provide parameters such as activation energy, Ea, and the reaction order (k) ADDIN EN.CITE <EndNote><Cite><Author>Flynn</Author><Year>1966</Year><RecNum>50</RecNum><DisplayText>[27]</DisplayText><record><rec-number>50</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497288997">50</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Flynn, Joseph H</author><author>Wall, Leo A</author></authors></contributors><titles><title>A quick, direct method for the determination of activation energy from thermogravimetric data</title><secondary-title>Journal of Polymer Science Part C: Polymer Letters</secondary-title></titles><periodical><full-title>Journal of Polymer Science Part C: Polymer Letters</full-title></periodical><pages>323-328</pages><volume>4</volume><number>5</number><dates><year>1966</year></dates><isbn>1542-6254</isbn><urls></urls></record></Cite></EndNote>[27].The optical microscopy was carried out on aged composite surfaces HiRox digital microscope – KH 7700 model. A scanning electron microscope (JSM-6490LV, JEOL) was used to observe MWCNTs used to prepare PP-MWCNT composite samples. A transmission electron microscope (TEM, JEM 2100, JEOL) was used to investigate the morphology of PP-MWCNT composites.2.4 Theoretical Analysis2.4.1 CrystallizationDSC studies are used to estimate the total crystalline content of polymers and composites based on the heat required to melt the polymer. An understanding of the degree of crystallinity of nanocomposite polymer as they age is important since crystallinity affects physical properties such as permeability, density, and melting point. For pristine and carbon nanotube reinforced polymer degree of crystallization, χ, can be quantified by measuring the heat associated with melting (fusion) of the polymer:χ= ?Ha?Hm (1-Wf) (1)Where Ha is measured melting enthalpies obtained from the experiment, by integrating the calorimetric signal. Wf is the weight fraction of MWCNT content and ?Hm is the enthalpy fusion of a perfect crystal of 100% polypropylene (207 J/g,) having infinite size PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5Mb25nbzwvQXV0aG9yPjxZZWFyPjIwMTE8L1llYXI+PFJl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ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5Mb25nbzwvQXV0aG9yPjxZZWFyPjIwMTE8L1llYXI+PFJl
Y051bT4zNDwvUmVjTnVtPjxEaXNwbGF5VGV4dD5bMjgtMzBdPC9EaXNwbGF5VGV4dD48cmVjb3Jk
PjxyZWMtbnVtYmVyPjM0PC9yZWMtbnVtYmVyPjxmb3JlaWduLWtleXM+PGtleSBhcHA9IkVOIiBk
Yi1pZD0iOTB2ZGRleGE4MHdmNWRlcHJ2N3h4cnJnMDA5MnhhZmFldnNlIiB0aW1lc3RhbXA9IjE0
ODc4Njc2NjIiPjM0PC9rZXk+PC9mb3JlaWduLWtleXM+PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwg
QXJ0aWNsZSI+MTc8L3JlZi10eXBlPjxjb250cmlidXRvcnM+PGF1dGhvcnM+PGF1dGhvcj5Mb25n
bywgQ2FyaW5hPC9hdXRob3I+PGF1dGhvcj5TYXZhcmlzLCBNaWNoZWxlPC9hdXRob3I+PGF1dGhv
cj5aZW5pLCBNw6FyYTwvYXV0aG9yPjxhdXRob3I+QnJhbmRhbGlzZSwgUm9zbWFyeSBOaWNoZWxl
PC9hdXRob3I+PGF1dGhvcj5HcmlzYSwgQW5hIE1hcmlhIENvdWxvbjwvYXV0aG9yPjwvYXV0aG9y
cz48L2NvbnRyaWJ1dG9ycz48dGl0bGVzPjx0aXRsZT5EZWdyYWRhdGlvbiBzdHVkeSBvZiBwb2x5
cHJvcHlsZW5lIChQUCkgYW5kIGJpb3JpZW50ZWQgcG9seXByb3B5bGVuZSAoQk9QUCkgaW4gdGhl
IGVudmlyb25tZW50PC90aXRsZT48c2Vjb25kYXJ5LXRpdGxlPk1hdGVyaWFscyBSZXNlYXJjaDwv
c2Vjb25kYXJ5LXRpdGxlPjwvdGl0bGVzPjxwZXJpb2RpY2FsPjxmdWxsLXRpdGxlPk1hdGVyaWFs
cyBSZXNlYXJjaDwvZnVsbC10aXRsZT48L3BlcmlvZGljYWw+PHBhZ2VzPjQ0Mi00NDg8L3BhZ2Vz
Pjx2b2x1bWU+MTQ8L3ZvbHVtZT48bnVtYmVyPjQ8L251bWJlcj48ZGF0ZXM+PHllYXI+MjAxMTwv
eWVhcj48L2RhdGVzPjxpc2JuPjE1MTYtMTQzOTwvaXNibj48dXJscz48L3VybHM+PC9yZWNvcmQ+
PC9DaXRlPjxDaXRlPjxBdXRob3I+TXV0bHVyPC9BdXRob3I+PFllYXI+MjAwNDwvWWVhcj48UmVj
TnVtPjMzPC9SZWNOdW0+PHJlY29yZD48cmVjLW51bWJlcj4zMzwvcmVjLW51bWJlcj48Zm9yZWln
bi1rZXlzPjxrZXkgYXBwPSJFTiIgZGItaWQ9IjkwdmRkZXhhODB3ZjVkZXBydjd4eHJyZzAwOTJ4
YWZhZXZzZSIgdGltZXN0YW1wPSIxNDg3ODY3NTkxIj4zMzwva2V5PjwvZm9yZWlnbi1rZXlzPjxy
ZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48Y29udHJpYnV0b3Jz
PjxhdXRob3JzPjxhdXRob3I+TXV0bHVyLCBTdWNoaXRyYTwvYXV0aG9yPjwvYXV0aG9ycz48L2Nv
bnRyaWJ1dG9ycz48dGl0bGVzPjx0aXRsZT5UaGVybWFsIEFuYWx5c2lzIG9mIENvbXBvc2l0ZXMg
VXNpbmcgRFNDPC90aXRsZT48c2Vjb25kYXJ5LXRpdGxlPkFkdmFuY2VkIFRvcGljcyBpbiBDaGFy
YWN0ZXJpemF0aW9uIG9mIENvbXBvc2l0ZXM8L3NlY29uZGFyeS10aXRsZT48L3RpdGxlcz48cGVy
aW9kaWNhbD48ZnVsbC10aXRsZT5BZHZhbmNlZCBUb3BpY3MgaW4gQ2hhcmFjdGVyaXphdGlvbiBv
ZiBDb21wb3NpdGVzPC9mdWxsLXRpdGxlPjwvcGVyaW9kaWNhbD48cGFnZXM+MTEtMzM8L3BhZ2Vz
PjxkYXRlcz48eWVhcj4yMDA0PC95ZWFyPjwvZGF0ZXM+PHVybHM+PC91cmxzPjwvcmVjb3JkPjwv
Q2l0ZT48Q2l0ZT48QXV0aG9yPlZhbiBkZXIgV2FsPC9BdXRob3I+PFllYXI+MTk5ODwvWWVhcj48
UmVjTnVtPjM1PC9SZWNOdW0+PHJlY29yZD48cmVjLW51bWJlcj4zNTwvcmVjLW51bWJlcj48Zm9y
ZWlnbi1rZXlzPjxrZXkgYXBwPSJFTiIgZGItaWQ9IjkwdmRkZXhhODB3ZjVkZXBydjd4eHJyZzAw
OTJ4YWZhZXZzZSIgdGltZXN0YW1wPSIxNDg3ODY3Njk2Ij4zNTwva2V5PjwvZm9yZWlnbi1rZXlz
PjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48Y29udHJpYnV0
b3JzPjxhdXRob3JzPjxhdXRob3I+VmFuIGRlciBXYWwsIEE8L2F1dGhvcj48YXV0aG9yPk11bGRl
ciwgSko8L2F1dGhvcj48YXV0aG9yPkdheW1hbnMsIFJKPC9hdXRob3I+PC9hdXRob3JzPjwvY29u
dHJpYnV0b3JzPjx0aXRsZXM+PHRpdGxlPkZyYWN0dXJlIG9mIHBvbHlwcm9weWxlbmU6IHRoZSBl
ZmZlY3Qgb2YgY3J5c3RhbGxpbml0eTwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5Qb2x5bWVyPC9z
ZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBlcmlvZGljYWw+PGZ1bGwtdGl0bGU+UG9seW1lcjwv
ZnVsbC10aXRsZT48L3BlcmlvZGljYWw+PHBhZ2VzPjU0NzctNTQ4MTwvcGFnZXM+PHZvbHVtZT4z
OTwvdm9sdW1lPjxudW1iZXI+MjI8L251bWJlcj48ZGF0ZXM+PHllYXI+MTk5ODwveWVhcj48L2Rh
dGVzPjxpc2JuPjAwMzItMzg2MTwvaXNibj48dXJscz48L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjwv
RW5kTm90ZT4A
ADDIN EN.CITE.DATA [28-30].2.4.2 Thermal Decomposition Iso-conversional Kinetic MethodMass loss data from the thermogravimetric analysis can be calculated into conversion, which is the actual mass of sample decomposed and can be defined as:α= m0-mtm0 (2)where mo is the initial mass of the sample and mt is the actual sample mass.In the kinetics of thermal decomposition of MWCNT using TGA, one can assume the rate of decomposition is a function of temperature and conversion:dαdt=kTg(α)(3)The temperature dependent function k(T) in Eq. (3) is the specific rate constant commonly by the Arrhenius equation:k=A e(-ERT)(4)is assumed for the temperature dependence of k, where A is the “pre-exponential factor,” (1/min), is assumed to be independent of temperature, E is the energy of activation (J/mol) and R is the gas constant (8.314 J/mol.K).The conversion function is usually expressed as:gα=(n-1)(1-α)n(5)where n is the order of the reaction.Therefore, the decomposition kinetics equation is obtained by combining the above three equations:dαdt=A exp-E(α)RT(1-α)n(6)The actual temperature under non-isothermal temperature ramping condition can beT= T0+βt(7)Where β is the heating rate (K/min) and To is the initial temperature (K). From Equation 6 and 7, it can be shown that:dαdT=Aβ exp-E(α)RT(1-α)n(8)The integrated expression of Eq. (8) is obtained asF(α)=0αdα(1-α)n=Aβ T0Texp-E(α)RTdT(9)Using Doyle’s approximation method ADDIN EN.CITE <EndNote><Cite><Author>Doyle</Author><Year>1961</Year><RecNum>22</RecNum><DisplayText>[31, 32]</DisplayText><record><rec-number>22</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">22</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Doyle, CD</author></authors></contributors><titles><title>Kinetic analysis of thermogravimetric data</title><secondary-title>Journal of applied polymer science</secondary-title></titles><periodical><full-title>Journal of Applied Polymer Science</full-title></periodical><pages>285-292</pages><volume>5</volume><number>15</number><dates><year>1961</year></dates><isbn>1097-4628</isbn><urls></urls></record></Cite><Cite><Author>Vyazovkin</Author><Year>2015</Year><RecNum>23</RecNum><record><rec-number>23</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">23</key></foreign-keys><ref-type name="Book">6</ref-type><contributors><authors><author>Vyazovkin, Sergey</author></authors></contributors><titles><title>Isoconversional kinetics of thermally stimulated processes</title></titles><dates><year>2015</year></dates><publisher>Springer</publisher><isbn>3319141759</isbn><urls></urls></record></Cite></EndNote>[31, 32] after integrating Equation (9) and using logarithms, it can be expressed as:lnβ=Constant-1.052E(α)RT (10)The apparent activation energy, E, can be estimated based on a slope of a linear plot of lnβ versus 1/T to obtain the activation energy as a function of conversion, α ADDIN EN.CITE <EndNote><Cite><Author>Vyazovkin</Author><Year>2015</Year><RecNum>23</RecNum><DisplayText>[32]</DisplayText><record><rec-number>23</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">23</key></foreign-keys><ref-type name="Book">6</ref-type><contributors><authors><author>Vyazovkin, Sergey</author></authors></contributors><titles><title>Isoconversional kinetics of thermally stimulated processes</title></titles><dates><year>2015</year></dates><publisher>Springer</publisher><isbn>3319141759</isbn><urls></urls></record></Cite></EndNote>[32]. Although the expressions used to evaluate these parameters are valid for fluid systems, not for solid-state reactions, they are useful in the elucidation of mechanism involved in polymer degradation.3. Results and Discussion3.1Characterization of pristine PP and PP-MWCNT nanocomposites with TGA and DSCSeveral reports have indicated increased thermal stability in nanotube-polymer composites ADDIN EN.CITE <EndNote><Cite><Author>Kim</Author><Year>2008</Year><RecNum>5</RecNum><DisplayText>[6]</DisplayText><record><rec-number>5</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">5</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Kim, J. Y., Han, S. I., Hong, S.</author></authors></contributors><titles><title>Effect of Modified carbon nanotube on the properties of aromatic polyester nanocomposites</title><secondary-title>Polymer</secondary-title></titles><periodical><full-title>Polymer</full-title></periodical><pages>3335-3345</pages><volume>49</volume><number>15</number><dates><year>2008</year></dates><urls></urls></record></Cite></EndNote>[6]. Non-isothermal thermogravimetric and differential scanning calorimetric behavior PP and PP-MWCNT composites were studied. TGA and DTG curves for a heating rate of 10 oC/min in air showed single-stage high-temperature degradation with the onset decomposition temperature, Tonset, around 400 oC with the maximum weight loss, Tpeak at 470 ± 2.6 oC and 480 ± 3.2 oC for PP and PP-MWCNT composites, respectively (Figure 2(a) and (b)). The mechanism for increased thermal stability could be due to dispersed nanotubes hindering the flux of degradation products which delay the onset of degradation, or the interaction between MWCNT and macromolecular chains of PP slow the degradation that shifts the Tpeak ADDIN EN.CITE <EndNote><Cite><Author>Chipara</Author><Year>2008</Year><RecNum>51</RecNum><DisplayText>[33]</DisplayText><record><rec-number>51</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497289173">51</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Chipara, Magdalena</author><author>Lozano, Karen</author><author>Hernandez, Anna</author><author>Chipara, Mircea</author></authors></contributors><titles><title>TGA analysis of polypropylene–carbon nanofibers composites</title><secondary-title>Polymer Degradation and Stability</secondary-title></titles><periodical><full-title>Polymer Degradation and Stability</full-title></periodical><pages>871-876</pages><volume>93</volume><number>4</number><dates><year>2008</year></dates><isbn>0141-3910</isbn><urls></urls></record></Cite></EndNote>[33].The small variations in the TGA result of PP samples could be attributed to manufacturing difference in crystal formation changes according to the heat treatment temperatures and cooling densities of thick wafers in using single screw PP sheet extrusion. The temperature of 50% weight loss (T50) for pure PP wafers, decreased slightly with the increased in thickness of samples (Figure 2 (b)). Polypropylene has a density ranging from 0.855 g/cm3 for the amorphous form to 0.946 g/cm3 full crystalline form, and melting temperature ranging from 130 to 170 oC. The decrease in T50 for the wafers of different thickness may be the result of the slight difference in crystallinity and density of thicker samples. The rapid cooling, when crystallized from melt state in the skin of injection mole could be a potential source of error in measured values. Since the lower pressure was applied to thicker wafers when the wafers came out from the extruder, thick wafers may have low density compared to thin wafers due to micron size air pockets. It suggests the added MWCNTs interacted with polypropylene, resulting in slightly improved thermal stability due to high mechanical and thermal stability of MWCNTs PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5Bc3NvdWxpbmU8L0F1dGhvcj48WWVhcj4yMDAzPC9ZZWFy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==
ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5Bc3NvdWxpbmU8L0F1dGhvcj48WWVhcj4yMDAzPC9ZZWFy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==
ADDIN EN.CITE.DATA [7, 8, 34].The melting points of pure and MWCNT filled PP were 163 ± 0.62 oC and 162 ± 0.6 oC, respectively, which shows the difference was statistically insignificant. However, the recrystallization temperature increased for MWCNTs filled PP (Figures 2 (c) and (d)), which suggests that the added MWCNTs act like nucleating agents for polypropylene recrystallization ADDIN EN.CITE <EndNote><Cite><Author>Manchado</Author><Year>2005</Year><RecNum>9</RecNum><DisplayText>[7]</DisplayText><record><rec-number>9</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">9</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Manchado, MA Lopez</author><author>Valentini, L</author><author>Biagiotti, J</author><author>Kenny, JM</author></authors></contributors><titles><title>Thermal and mechanical properties of single-walled carbon nanotubes–polypropylene composites prepared by melt processing</title><secondary-title>Carbon</secondary-title></titles><periodical><full-title>Carbon</full-title></periodical><pages>1499-1505</pages><volume>43</volume><number>7</number><dates><year>2005</year></dates><isbn>0008-6223</isbn><urls></urls></record></Cite></EndNote>[7]. This result is somewhat different from the effects of single walled carbon nanotube on non-isothermal crystallization of polyethylene, where it showed no significant change ADDIN EN.CITE <EndNote><Cite><Author>Li</Author><Year>2009</Year><RecNum>53</RecNum><DisplayText>[35]</DisplayText><record><rec-number>53</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497289362">53</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Li, Lingyu</author><author>Li, Bing</author><author>Hood, Matthew A</author><author>Li, Christopher Y</author></authors></contributors><titles><title>Carbon nanotube induced polymer crystallization: The formation of nanohybrid shish–kebabs</title><secondary-title>Polymer</secondary-title></titles><periodical><full-title>Polymer</full-title></periodical><pages>953-965</pages><volume>50</volume><number>4</number><dates><year>2009</year></dates><isbn>0032-3861</isbn><urls></urls></record></Cite></EndNote>[35]. The increased recrystallization temperature of PP-MWCNT mix may restrict sites for polypropylene segment, which inhibited the formation of highly ordered spherulites and affects the mechanism of nucleation and crystal growth ADDIN EN.CITE <EndNote><Cite><Author>Assouline</Author><Year>2003</Year><RecNum>52</RecNum><DisplayText>[7, 34]</DisplayText><record><rec-number>52</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497289280">52</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Assouline, E</author><author>Lustiger, A</author><author>Barber, AH</author><author>Cooper, CA</author><author>Klein, E</author><author>Wachtel, E</author><author>Wagner, HD</author></authors></contributors><titles><title>Nucleation ability of multiwall carbon nanotubes in polypropylene composites</title><secondary-title>Journal of Polymer Science Part B: Polymer Physics</secondary-title></titles><periodical><full-title>Journal of Polymer Science Part B: Polymer Physics</full-title></periodical><pages>520-527</pages><volume>41</volume><number>5</number><dates><year>2003</year></dates><isbn>1099-0488</isbn><urls></urls></record></Cite><Cite><Author>Manchado</Author><Year>2005</Year><RecNum>9</RecNum><record><rec-number>9</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="0">9</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Manchado, MA Lopez</author><author>Valentini, L</author><author>Biagiotti, J</author><author>Kenny, JM</author></authors></contributors><titles><title>Thermal and mechanical properties of single-walled carbon nanotubes–polypropylene composites prepared by melt processing</title><secondary-title>Carbon</secondary-title></titles><periodical><full-title>Carbon</full-title></periodical><pages>1499-1505</pages><volume>43</volume><number>7</number><dates><year>2005</year></dates><isbn>0008-6223</isbn><urls></urls></record></Cite></EndNote>[7, 34]. The narrow, symmetrical and uniform crystallization curves suggest that heterogeneous nucleation is the predominant crystallization mechanism.3.2. Weathering stress cracking of MWCT-PP compositeSemi-crystalline polymers, like polypropylene, are essentially two phases systems containing spherulitic clusters of crystals surrounded by a continuum of amorphous substance. During the process of aging, PP and PP-MWCNT composites lose their elasticity, become brittle and crack. The light-water spray cycle resulted in photooxidation and hydrolysis resulting in environmental stress cracking. Oxygen diffusions readily through the amorphous region but are highly limited through the crystalline regions. Thus, most of the aging occurs at the spherulite boundaries and weakens the “glue” that holds the crystalline region together. Figure 3 shows SEM and optical microscopic images of pristine and aged polypropylene wafers of increasing thickness PP01, PP02 and PP03. The time for the formation of cracking and crumbling is inversely proportional to the sample thickness following PP01 > PP02 > PP03. There was craze forming as part of crack initiation and continuing formation and growth of cracks with increasing aging, as the PP wafers became increasingly become brittle.Although PP-MWCNT composites showed higher resistance to aging cracks, increased exposure resulted in significant changes in the surface structures (Figure 4(a) to 4(d)). Aged samples showed exfoliation, surface holes and cracks were evident. The depth in the surface cracks for sample PP42 increased from 15 ?m to more than 80 ?m as the aging time increased from 756 h to 2200 h, respectively (Figure 4(c) and 4(d) inserts). The thickness of the oxidized layer can be seen from the depth of the cracked samples (Figure 4(c) to (d)), which is proportional to the UV-aging time or dose.Aging changes PP structure at the macromolecular, molecular, and the morphological level and thus induce variations in the chemical and structural properties. These exposed surfaces show cracks propagation that increases with the aging time in the stove and penetrates the layer near the surface. The diffusion of oxygen is considered as significant in accelerated test, especially in rapidly oxidizing polymers. Like most semi-crystalline polymers, PP oxidizes exclusively in the amorphous phase because the crystalline phase is impermeable to oxygen. Due to the presence of methyl group in the tertiary carbon atom of PP monomer backbone, the formation of unstable secondary free radicals possible at oxidative conditions. This reaction is kinetically controlled by the diffusion of O2 and H2O in the polymer. Thus, the degraded layer of the PP is in the order of the ratio of the diffusion coefficient and the pseudo-first order kinetic coefficient of the rate constant, D/k PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5BdWRvdWluPC9BdXRob3I+PFllYXI+MTk5NDwvWWVhcj48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ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5BdWRvdWluPC9BdXRob3I+PFllYXI+MTk5NDwvWWVhcj48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ADDIN EN.CITE.DATA [36-38].3.3. Effect of Aging on Thermal Stability of PP and PP-MWCNT compositesThe presence of tertiary carbon in the chemical structure of PP results in the degradation and changes structural properties PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5HdWd1bXVzPC9BdXRob3I+PFllYXI+MTk5OTwvWWVhcj48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=
ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5HdWd1bXVzPC9BdXRob3I+PFllYXI+MTk5OTwvWWVhcj48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=
ADDIN EN.CITE.DATA [39-42]. Aging of PP causes structural changes, which are typically chain session and crosslinking. TGA measurements of polymers provide information on the thermal stability, composition, decomposition profiles and their products. The thermal stabilities of pristine and MWCNT filled PP having three different thickness both before and after environmental aging were investigated by TGA measurement. The pyrolysis kinetics studies of were conducted based on weight loss versus temperature the sample was heated at the rate of 10 oC/min. Thermogravimetric curves for pristine, PP01, PP02, and PP03 and MWCNT loaded, PP41, PP42 and PP43 samples (Figure 5(a) to 5(f)), respectively. PP degrades by a single mechanism for all pristine and aged samples, which suggests involving the similar rate-controlling step. However, the TGA curves indicate the aged samples exhibited a significant reduction in thermal stability with increased in exposure time. The temperature at 50% weight loss, T50, decreased with an increase in a weathering duration from 470 oC ± oC to around 437 oC ± oC. The thinnest wafers, PP01, crumbled after 1512 h of aging, which was equivalent to an outdoor exposure of 6.9 months in Florida, U.S.A, showing a remarkable decrease in T50 from 470 oC to 434 oC within a short exposure time (Figure 5 (a)). The PP thermal stability is affected by factors such as the presence of additives substances, changes in crosslinking due to aging and the presence of aromatic rings and decomposing functional groups.DTG data of these samples show the decrease in the Tpeak as the aging time increased (Supplemental Figure S3). PP01 samples were broken into smaller pieces after 1512 h, and they were removed from the weathering chamber and the study. PP02 wafers having thickness 0.39 ± 0.02 mm, were fragmented after 2268 h, whereas PP03 (0.69 ± 0.04 mm) remained intact during the remaining test period of 3024 h. Surface crack formations have been associated with the contraction of the surface layer and the formation of chemi-crystallization ADDIN EN.CITE <EndNote><Cite><Author>De Paoli</Author><Year>2009</Year><RecNum>61</RecNum><DisplayText>[43]</DisplayText><record><rec-number>61</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497290304">61</key></foreign-keys><ref-type name="Book">6</ref-type><contributors><authors><author>De Paoli, Marco Aurelio</author></authors></contributors><titles><title>Degrada??o e estabiliza??o de polímeros</title></titles><dates><year>2009</year></dates><publisher>Artliber S?o Paulo</publisher><isbn>858809844X</isbn><urls></urls></record></Cite></EndNote>[43]. As the intensity of cracking increased with longer aging the materials becomes more fragile. These results showed the effects of photooxidation originate on the exposed surface and diffuse into the inner matrix, thus strength of the sample during aging depended on sample thickness. TGA studies were conducted to monitor the decrease in T50, of PP-MWCNT composite specimens after weathering for selected time lengths. TGA curves for both pristine and PP-MWCNT composites exhibited a one-step decomposition, although the DTG curves for aged samples were increasingly wider with increased aging time. The TGA data for the three samples of increasing thickness initial and aged the PP-MWCNT composite are shown in Figures 5(d), 5(e) and 5(f). The thickest PP-MWCNT composites demonstrated the highest thermal stability with a T50 value of 464 oC after 3024 h weathering. Previous studies reported thermal stability of aged polymer samples decreased due to a combination of photolysis, photooxidation, and thermal degradation of samples PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5Ccnpvem93c2thLVN0YW51Y2g8L0F1dGhvcj48WWVhcj4y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=
ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5Ccnpvem93c2thLVN0YW51Y2g8L0F1dGhvcj48WWVhcj4y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=
ADDIN EN.CITE.DATA [44-46]. Moreover, due to the MWCNT reinforcement, all PP-MWCNT composite samples displayed little structural break down during the full weathering period of 3024 h that is equivalent to 13.9 months of outdoor weathering.TGA data shows a slight drop in sample weights at temperatures below 250 oC for aged PP wafers that may account for the loss of absorbed water, which promotes further degradation and impacted the dimensional stability of the wafers (Figure 5(a), 5(b) and 5(c)). Previous studies have revealed that absorbed water may exist in a polymer as free water or loosely bound water. Bound water can escape out polymer easily upon heating, and tightly bound water, which is strongly confined in the polymer network and requires additional energy for removal from the polymer ADDIN EN.CITE <EndNote><Cite><Author>Bumbudsanpharoke</Author><Year>2015</Year><RecNum>36</RecNum><DisplayText>[47]</DisplayText><record><rec-number>36</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1489707654">36</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Bumbudsanpharoke, Nattinee</author><author>Ko, Seonghyuk</author></authors></contributors><titles><title>A Study of Thermal Properties of LDPE-Nanoclay Composite Films</title><secondary-title>Korean Journal of Packaging Science & Technology</secondary-title></titles><periodical><full-title>Korean Journal of Packaging Science & Technology</full-title></periodical><pages>107-113</pages><volume>21</volume><number>3</number><dates><year>2015</year></dates><isbn>1226-0207</isbn><urls></urls></record></Cite></EndNote>[47]. PP-MWCNT composites showed little or no absorption of moisture even after 3024 h of aging. Decomposition of PP due to weathering was caused due to thermal, oxidative and hydrolytic reactions.3.4. Environmental aging and changes in melting point Differential scanning calorimetry (DSC) allows analysis of thermal effects and monitoring the effects of environmental aging on various phenomena, including melting, crystallization, polymorphism, or specific heat. DSC analysis was done to monitor changes in melting and crystallization temperatures of PP and PP-MWCNT samples that were kept in the accelerated weathering chamber for selected times. The data presented in Figure 6 and 7 show changes in melting and crystallization temperatures of aged samples before and after aging for pristine PP and PP-MWCNT composites, respectively. The critical phase change data are summarized in Table 5.Melting point depression of PP and PP-MWCNT were observed due to molecular chain scission and formation of carbonyl and hydroperoxide groups. The results of DSC analysis in Figure 6 (a)-(c) showing the melting point, Tm, depression from 162.9 to 142.5 oC for PP01 after 1512 h of accelerated aging, and from 163.8 to 140.0 oC for PP02 after 2268 hr. The drop in Tm for PP03 after 3024 h was from 164.1 to 144.3 oC. Due to structural changes of aged samples by chain scission and oxidation, more aged samples began to melt at lower temperatures, resulting in broadened temperature of melting of samples. A similar trend of a decrease of melting temperatures and extended temperature ranges of melting was observed for aged PP-MWCNT composites (Figure 7(a)-(c)). However, the changes in melting temperatures were not as significant as the pristine PP. The measured Tm values for all initial and after different environmental aging times are shown in Figure 7(d). The changes in the melting and crystallization temperatures reflect the reduction in molecular weight and changes in the degree of crystallinity of polymer matrix that is caused by photolysis, photooxidation, and thermal degradation during weathering. These effects are more significant for thin samples of pristine PP than PP-MWCNT. Figures 7 (b), (d) and (e) show smaller changes in melting and crystallization temperatures of PP-MWCNTs composites than aged-pristine PP. However, all samples show a broadening of melting that increased with aging. The largest change observed was 12.1 oC for PP41 and the smallest changes observed was 2.4 oC for PP43 while melting temperatures of PP01 decreased over 20 oC after 1512 h of aging. These results indicate that added MWCNTs significantly increase the thermal stability of PP. The difference of both melting and crystallization temperatures before and after weathering of PP-MWCNT composites diminished with the increase in wafer thickness. Both Tm and Tc of all aged PP-MWCNTs were higher than aged pristine PP, indicating MWCNTs significantly improved the thermal stability of polypropylene.Brzozowska-stanuch et al. ADDIN EN.CITE <EndNote><Cite><Author>Brzozowska-Stanuch</Author><Year>2014</Year><RecNum>37</RecNum><DisplayText>[44]</DisplayText><record><rec-number>37</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1489709007">37</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Brzozowska-Stanuch, Anna</author><author>Rabiej, Stanis?aw</author><author>Fabia, Janusz</author><author>Nowak, Jan</author></authors></contributors><titles><title>Changes in thermal properties of isotactic polypropylene with different additives during aging process</title><secondary-title>Polimery</secondary-title></titles><periodical><full-title>Polimery</full-title></periodical><pages>302--307</pages><volume>59</volume><number>4</number><dates><year>2014</year></dates><isbn>0032-2725</isbn><urls></urls></record></Cite></EndNote>[44] studied thermal property changes of polypropylene containing different materials (i.e., montmorillonite, compatibilizer, MWCNTs, and blue pigment) by UV aging following the standard method by Society of Automotive Engineers (SAE J2527). They reported melting, and crystallization temperatures of aged polypropylene composites decreased due to structural changes such as polymer chains shortening in the aged samples and found minimal changes in thermal stability of samples containing MWCNTs by UV ADDIN EN.CITE <EndNote><Cite><Author>Brzozowska-Stanuch</Author><Year>2014</Year><RecNum>37</RecNum><DisplayText>[44]</DisplayText><record><rec-number>37</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1489709007">37</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Brzozowska-Stanuch, Anna</author><author>Rabiej, Stanis?aw</author><author>Fabia, Janusz</author><author>Nowak, Jan</author></authors></contributors><titles><title>Changes in thermal properties of isotactic polypropylene with different additives during aging process</title><secondary-title>Polimery</secondary-title></titles><periodical><full-title>Polimery</full-title></periodical><pages>302--307</pages><volume>59</volume><number>4</number><dates><year>2014</year></dates><isbn>0032-2725</isbn><urls></urls></record></Cite></EndNote>[44]. The decrease of two temperatures lessened when a thickness of samples increased, which signified the decomposition of polymers by weathering started on the surface of polymers. In particular, changes of both melting and crystallization temperatures of the PP43 sample are very small, only 2 oC decrease, implying that MWCNTs reinforced thermal property of polypropylene and polymer decomposition by weathering occurs at polymer’s surface and then inside of the polymers gradually was degraded ADDIN EN.CITE <EndNote><Cite><Author>Bumbudsanpharoke</Author><Year>2015</Year><RecNum>36</RecNum><DisplayText>[47, 48]</DisplayText><record><rec-number>36</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1489707654">36</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Bumbudsanpharoke, Nattinee</author><author>Ko, Seonghyuk</author></authors></contributors><titles><title>A Study of Thermal Properties of LDPE-Nanoclay Composite Films</title><secondary-title>Korean Journal of Packaging Science & Technology</secondary-title></titles><periodical><full-title>Korean Journal of Packaging Science & Technology</full-title></periodical><pages>107-113</pages><volume>21</volume><number>3</number><dates><year>2015</year></dates><isbn>1226-0207</isbn><urls></urls></record></Cite><Cite><Author>Pires</Author><Year>2015</Year><RecNum>38</RecNum><record><rec-number>38</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1489709490">38</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Pires, Homero Modesto</author><author>Mendes, Luis Claudio</author><author>Cestari, Sibele Piedade</author><author>Pita, Victor Jayme Roget Rodriguez</author></authors></contributors><titles><title>Effect of Weathering and Accelerated Photoaging on PET/PC (80/20 wt/wt%) Melt Extruded Blend</title><secondary-title>Materials Research</secondary-title></titles><periodical><full-title>Materials Research</full-title></periodical><pages>763-768</pages><volume>18</volume><number>4</number><dates><year>2015</year></dates><isbn>1516-1439</isbn><urls></urls></record></Cite></EndNote>[47, 48].3.5. Environmental aging and recrystallization The estimated degree of crystallinity of aged samples increased by weathering (Figure 6 (d)) and thicker samples were slowly crystallized than thinner samples. Previous studies PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5CaGF0ZWphPC9BdXRob3I+PFllYXI+MTk4MzwvWWVhcj48
UmVjTnVtPjM5PC9SZWNOdW0+PERpc3BsYXlUZXh0Pls0OS01MV08L0Rpc3BsYXlUZXh0PjxyZWNv
cmQ+PHJlYy1udW1iZXI+Mzk8L3JlYy1udW1iZXI+PGZvcmVpZ24ta2V5cz48a2V5IGFwcD0iRU4i
IGRiLWlkPSI5MHZkZGV4YTgwd2Y1ZGVwcnY3eHhycmcwMDkyeGFmYWV2c2UiIHRpbWVzdGFtcD0i
MTQ5MDAzOTI0NiI+Mzk8L2tleT48L2ZvcmVpZ24ta2V5cz48cmVmLXR5cGUgbmFtZT0iSm91cm5h
bCBBcnRpY2xlIj4xNzwvcmVmLXR5cGU+PGNvbnRyaWJ1dG9ycz48YXV0aG9ycz48YXV0aG9yPkJo
YXRlamEsIFNLPC9hdXRob3I+PC9hdXRob3JzPjwvY29udHJpYnV0b3JzPjx0aXRsZXM+PHRpdGxl
PlJhZGlhdGlvbuKAkGluZHVjZWQgY3J5c3RhbGxpbml0eSBjaGFuZ2VzIGluIGxpbmVhciBwb2x5
ZXRoeWxlbmU6IEluZmx1ZW5jZSBvZiBhZ2luZzwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5Kb3Vy
bmFsIG9mIEFwcGxpZWQgUG9seW1lciBTY2llbmNlPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+
PHBlcmlvZGljYWw+PGZ1bGwtdGl0bGU+Sm91cm5hbCBvZiBBcHBsaWVkIFBvbHltZXIgU2NpZW5j
ZTwvZnVsbC10aXRsZT48L3BlcmlvZGljYWw+PHBhZ2VzPjg2MS04NzI8L3BhZ2VzPjx2b2x1bWU+
Mjg8L3ZvbHVtZT48bnVtYmVyPjI8L251bWJlcj48ZGF0ZXM+PHllYXI+MTk4MzwveWVhcj48L2Rh
dGVzPjxpc2JuPjEwOTctNDYyODwvaXNibj48dXJscz48L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjxD
aXRlPjxBdXRob3I+QmhhdGVqYTwvQXV0aG9yPjxZZWFyPjE5ODk8L1llYXI+PFJlY051bT40MDwv
UmVjTnVtPjxyZWNvcmQ+PHJlYy1udW1iZXI+NDA8L3JlYy1udW1iZXI+PGZvcmVpZ24ta2V5cz48
a2V5IGFwcD0iRU4iIGRiLWlkPSI5MHZkZGV4YTgwd2Y1ZGVwcnY3eHhycmcwMDkyeGFmYWV2c2Ui
IHRpbWVzdGFtcD0iMTQ5MDAzOTQyMiI+NDA8L2tleT48L2ZvcmVpZ24ta2V5cz48cmVmLXR5cGUg
bmFtZT0iSm91cm5hbCBBcnRpY2xlIj4xNzwvcmVmLXR5cGU+PGNvbnRyaWJ1dG9ycz48YXV0aG9y
cz48YXV0aG9yPkJoYXRlamEsIFNLPC9hdXRob3I+PGF1dGhvcj5BbmRyZXdzLCBFSDwvYXV0aG9y
PjxhdXRob3I+WWFyYnJvdWdoLCBTTTwvYXV0aG9yPjwvYXV0aG9ycz48L2NvbnRyaWJ1dG9ycz48
dGl0bGVzPjx0aXRsZT5SYWRpYXRpb24gaW5kdWNlZCBjcnlzdGFsbGluaXR5IGNoYW5nZXMgaW4g
bGluZWFyIHBvbHlldGh5bGVuZXM6IGxvbmcgdGVybSBhZ2luZyBlZmZlY3RzPC90aXRsZT48c2Vj
b25kYXJ5LXRpdGxlPlBvbHltZXIgam91cm5hbDwvc2Vjb25kYXJ5LXRpdGxlPjwvdGl0bGVzPjxw
ZXJpb2RpY2FsPjxmdWxsLXRpdGxlPlBvbHltZXIgam91cm5hbDwvZnVsbC10aXRsZT48L3Blcmlv
ZGljYWw+PHBhZ2VzPjczOS03NTA8L3BhZ2VzPjx2b2x1bWU+MjE8L3ZvbHVtZT48bnVtYmVyPjk8
L251bWJlcj48ZGF0ZXM+PHllYXI+MTk4OTwveWVhcj48L2RhdGVzPjxpc2JuPjAwMzItMzg5Njwv
aXNibj48dXJscz48L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjxDaXRlPjxBdXRob3I+R2FsPC9BdXRo
b3I+PFllYXI+MTk4NjwvWWVhcj48UmVjTnVtPjQxPC9SZWNOdW0+PHJlY29yZD48cmVjLW51bWJl
cj40MTwvcmVjLW51bWJlcj48Zm9yZWlnbi1rZXlzPjxrZXkgYXBwPSJFTiIgZGItaWQ9IjkwdmRk
ZXhhODB3ZjVkZXBydjd4eHJyZzAwOTJ4YWZhZXZzZSIgdGltZXN0YW1wPSIxNDkwMDQwNTMxIj40
MTwva2V5PjwvZm9yZWlnbi1rZXlzPjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3
PC9yZWYtdHlwZT48Y29udHJpYnV0b3JzPjxhdXRob3JzPjxhdXRob3I+R2FsLCBPPC9hdXRob3I+
PGF1dGhvcj5Lb3N0b3NraSwgRDwvYXV0aG9yPjxhdXRob3I+QmFiacSHLCBEPC9hdXRob3I+PGF1
dGhvcj5TdGFubmV0dCwgVlQ8L2F1dGhvcj48L2F1dGhvcnM+PC9jb250cmlidXRvcnM+PHRpdGxl
cz48dGl0bGU+RFNDIG1lbHRpbmcgYmVoYXZpb3Igb2YgaXJyYWRpYXRlZCBsb3cgZGVuc2l0eSBw
b2x5ZXRoeWxlbmVzIGNvbnRhaW5pbmcgYW50aW94aWRhbnRzPC90aXRsZT48c2Vjb25kYXJ5LXRp
dGxlPkludGVybmF0aW9uYWwgSm91cm5hbCBvZiBSYWRpYXRpb24gQXBwbGljYXRpb25zIGFuZCBJ
bnN0cnVtZW50YXRpb24uIFBhcnQgQy4gUmFkaWF0aW9uIFBoeXNpY3MgYW5kIENoZW1pc3RyeTwv
c2Vjb25kYXJ5LXRpdGxlPjwvdGl0bGVzPjxwZXJpb2RpY2FsPjxmdWxsLXRpdGxlPkludGVybmF0
aW9uYWwgSm91cm5hbCBvZiBSYWRpYXRpb24gQXBwbGljYXRpb25zIGFuZCBJbnN0cnVtZW50YXRp
b24uIFBhcnQgQy4gUmFkaWF0aW9uIFBoeXNpY3MgYW5kIENoZW1pc3RyeTwvZnVsbC10aXRsZT48
L3BlcmlvZGljYWw+PHBhZ2VzPjI1OS0yNjc8L3BhZ2VzPjx2b2x1bWU+Mjg8L3ZvbHVtZT48bnVt
YmVyPjM8L251bWJlcj48ZGF0ZXM+PHllYXI+MTk4NjwveWVhcj48L2RhdGVzPjxpc2JuPjEzNTkt
MDE5NzwvaXNibj48dXJscz48L3VybHM+PC9yZWNvcmQ+PC9DaXRlPjwvRW5kTm90ZT5=
ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5CaGF0ZWphPC9BdXRob3I+PFllYXI+MTk4MzwvWWVhcj48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=
ADDIN EN.CITE.DATA [49-51] reported similar results that showed an increase in crystallinity of polymer samples after aging, which could be the reduction of amorphous fraction and rearrangement of crystals induced by chain scission and changes of molecular size during the aging process. However, due to the complexity of changes in structural and chemical properties of polymers during aging processes, the crystallinity may increase or decrease ADDIN EN.CITE <EndNote><Cite><Author>Carrasco</Author><Year>2001</Year><RecNum>42</RecNum><DisplayText>[52]</DisplayText><record><rec-number>42</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1490041304">42</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Carrasco, F</author><author>Pages, P</author><author>Pascual, S</author><author>Colom, X</author></authors></contributors><titles><title>Artificial aging of high-density polyethylene by ultraviolet irradiation</title><secondary-title>European polymer journal</secondary-title></titles><periodical><full-title>European polymer journal</full-title></periodical><pages>1457-1464</pages><volume>37</volume><number>7</number><dates><year>2001</year></dates><isbn>0014-3057</isbn><urls></urls></record></Cite></EndNote>[52].In addition to investigating thermal properties of aged PP and PP-MWCNT composites, a simple DSC analysis was performed evaluate the aging of the polymer along its depth from the irradiation exposed The thickest sample, PP43, was chosen because three different parts (i.e., top (exposed surface toward solar light), middle (inside), and bottom (unexposed surface)) were taken from this sample only due to its thickness of about 2 mm. As seen Figure 7 (a), melting temperatures of different parts varied with a difference of 2 oC at time 0 and degree of crystallinity of each part was about 4.6% for the top part, 6.0% for the middle part, and 3.7% for the bottom part. As the aging advance, the degree of crystallinity of top and bottom parts PP gradually increased. Samples were taken from the surface of irradiated coupons after selected aging times exhibited increasing degree of crystallinity. However, the changes in crystallinity were less significant for the unexposed side of the coupon (Figure 7(d)). These changes in crystallinity imply that photolysis and photooxidation mainly occur at the surface of samples exposed to solar light and accumulated heat triggers thermal degradation of samples from the surface to the inside, resulting in the decomposition of inside of samples by a long term aging process. The DSC data on the effects of aging on the melting and recrystallization temperatures of unfilled PP and PP-MWCNT composite are summarized in Figures 8(a) and 8(b). The melting temperature depression was measured by the rate of ~1 oC for every 75 h (for PP01) to 110 h (PP03) of exposure depending on the panel thickness. For PP-MWCNT 1 oC decrease in melting point was measured ranging from every 150 oC for the thin wafers (PP41) to every 320 oC for PP43 (Figure 8(a)). DSC measures showed the recrystallization temperatures were more than 10 oC higher for the PP-MWCNT composite and were not affected by aging, although the decree of crystallinity increased (Figures 8(b) and 8(d)). The decrease in stability of polymer is shown based on the declining T50 with aging time, which indicate changes in polymer molecular structures (Figure 8(c)). The slope of this decline depends on the thickness of the sample and composition that shows the photooxidation of polymers is primarily a surface phenomenon.3.6. Thermogravimetric analysis of aged polypropylene-MWCNTThis study included estimating the change in one of kinetic parameters, the activation energy, Ea, for pristine and aged PP and PP-MWCNT composites. The activation is the most important kinetic parameter, which can be used to predict material storage and operating life ADDIN EN.CITE <EndNote><Cite><Author>Bystritskaya</Author><Year>2013</Year><RecNum>64</RecNum><DisplayText>[53]</DisplayText><record><rec-number>64</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497290713">64</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Bystritskaya, Elena V</author><author>Monakhova, Tatyana V</author><author>Ivanov, Victor B</author></authors></contributors><titles><title>TGA application for optimising the accelerated aging conditions and predictions of thermal aging of rubber</title><secondary-title>Polymer testing</secondary-title></titles><periodical><full-title>Polymer testing</full-title></periodical><pages>197-201</pages><volume>32</volume><number>2</number><dates><year>2013</year></dates><isbn>0142-9418</isbn><urls></urls></record></Cite></EndNote>[53]. Isoconversional kinetics is an easy-to-use method for kinetics evaluation and is capable of good approximation of complex experimental data. The rate of thermal degradation can be parametrized regarding the extent of conversion as a function of temperature. However, the method is not linked directly to the particular species or reaction molecules of the aged composites. The method typically reflects the overall transformation of the various reactants to products.We calculated the activation energy, Ea, for values varying from 0.05 to 0.95 at a step of 0.05. The values of Ea evaluated using the isoconversion method allow a meaningful mechanism and analysis of decomposition kinetics. For the estimation of activation energy, TGA analysis of all samples was conducted by at selected heating rates of 10, 20, 40, or 50 oC min-1. From the set of data of these different heating rates, the isoconversional lines for predefined conversion were calculated, based on Equation 10, section 2.4. The linear plots of ln β versus 1/T for aged samples of PP and PP-MWCNT composites with different conversion values, α, to estimate thermal decomposition kinetic parameter, Ea, were calculated from slopes of the linear plots in Figures S5-S10. The estimated effective activation energy values are shown in Figures 9 (a)-(f). At α=0.1, the activation energy for pristine PP01, PP02 and PP03 was 338, 338, and 346 KJ mol-1, respectively. PP-MWCNT composites had a higher activation energy, which was 380 KJ mol-1, 280 KJ mol-1 and 350 KJ mol-1 for PP41, PP2, and PP43, respectively, which confirms increased in thermal stability. It is evident the activation energies after aging decreased significantly with longer aging time. The activation energies for thermal decomposition for material loss from 10% to 50% conversion were significantly lower, which reveals that dominant kinetic process is changing. These results are similar to the values reported in the literature ADDIN EN.CITE <EndNote><Cite><Author>Peterson</Author><Year>2001</Year><RecNum>65</RecNum><DisplayText>[54]</DisplayText><record><rec-number>65</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1497290791">65</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Peterson, Jeffery D</author><author>Vyazovkin, Sergey</author><author>Wight, Charles A</author></authors></contributors><titles><title>Kinetics of the thermal and thermo-oxidative degradation of polystyrene, polyethylene and poly (propylene)</title><secondary-title>Macromolecular Chemistry and Physics</secondary-title></titles><periodical><full-title>Macromolecular Chemistry and Physics</full-title></periodical><pages>775-784</pages><volume>202</volume><number>6</number><dates><year>2001</year></dates><isbn>1022-1352</isbn><urls></urls></record></Cite></EndNote>[54]. The activation energy of aged PP01, PP02 and PP03 at 50% conversion indicated significant reduction to 156 KJ mol-1, 128 KJ mol-1, 195 KJ mol-1 after exposure from 1500 to 3024 h. The reduction in the activation energy of aged PP-MWCNT composites were lower than pristine material but not as significant as unfilled PP. The value of Ea for the pristine PP and PP-MWCNT composite was nearly constant with thermal conversion, ?. However, for the aged samples, the significant variation in Ea indicates the thermally stimulated decomposition processes are kinetically complex. The increased non-linear relationship of Ea with conversion as the PP and PP-MWCNT composites age indicted multistep decomposition kinetics. Weathering degrades the molecular structure of the amorphous fraction and disintegrated weak links that fragmented polymer chains and added carbonyls resulting in a decrease of the activation energy. However, varied patterns of the estimated activation energy over weathering times were observed for each sample due to the complexity of changes in structural and chemical properties during polymer degradation ADDIN EN.CITE <EndNote><Cite><Author>Carrasco</Author><Year>2001</Year><RecNum>42</RecNum><DisplayText>[52, 55]</DisplayText><record><rec-number>42</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1490041304">42</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Carrasco, F</author><author>Pages, P</author><author>Pascual, S</author><author>Colom, X</author></authors></contributors><titles><title>Artificial aging of high-density polyethylene by ultraviolet irradiation</title><secondary-title>European polymer journal</secondary-title></titles><periodical><full-title>European polymer journal</full-title></periodical><pages>1457-1464</pages><volume>37</volume><number>7</number><dates><year>2001</year></dates><isbn>0014-3057</isbn><urls></urls></record></Cite><Cite><Author>Chigwada</Author><Year>2008</Year><RecNum>44</RecNum><record><rec-number>44</rec-number><foreign-keys><key app="EN" db-id="90vddexa80wf5deprv7xxrrg0092xafaevse" timestamp="1490130235">44</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Chigwada, Grace</author><author>Kandare, Everson</author><author>Wang, Dongyan</author><author>Majoni, Stephen</author><author>Mlambo, Darlington</author><author>Wilkie, Charles A</author><author>Hossenlopp, Jeanne M</author></authors></contributors><titles><title>Thermal stability and degradation kinetics of polystyrene/organically-modified montmorillonite nanocomposites</title><secondary-title>Journal of nanoscience and nanotechnology</secondary-title></titles><periodical><full-title>Journal of nanoscience and nanotechnology</full-title></periodical><pages>1927-1936</pages><volume>8</volume><number>4</number><dates><year>2008</year></dates><isbn>1533-4880</isbn><urls></urls></record></Cite></EndNote>[52, 55]. Moreover, the activation energy for thin samples rapidly decreased compared to thicker samples, indicating that polymer degradation startes from the surface of samples and proceeded to the inner matrix of the samples.4. ConclusionsThe aging properties of PP and PP-MWCNT were investigated using thermal analysis techniques to discern?the effects of wafer thickness and the filling of MWCNT. Environmental aging of PP has a significant influence on changes in T50, melting and crystallization temperatures, the degree of crystallinity, and the thermal decomposition kinetic parameter, activation energy. TGA analysis showed that T50 values decreased significantly for the pristine PP that were weathered, and this decrease had a direct correlation with the square root of aging time (T50 = a? + b). Thin PP wafer samples crumbled in the middle of the test period, which confirmed that accelerated aging is controlled by surface reaction mechanism. All tests performed comparing pristine PP with MWCNT-PP composite showed that MWCNT loading increased the thermal stability of PP. Melting and crystallization temperatures decreased with longer weathering times, but the degree of crystallinity increased in all aged samples. There was a remarkable decrease in melting and crystallization temperatures in aged PP samples. For PP01 coupons, a 20 oC dropped in the melting temperature was measured after 1512 h of weathering while a reduction of 12 oC was observed for aged PP41 for 3024 h of aging. The increased in stability is due to the presence of MWCNTs in PP-MWCNT composites. In all samples, the decrease of melting and crystallization temperatures was inversely proportional to a thickness of samples during the aging process, but the crystallinity of samples was independent to sample depths and increased by rearrangement of crystals induced by chain scission and changes of molecular size during the aging process. The activation energy was estimated as one of the kinetic parameters of polymer degradation. At α=0.1, the activation energy of all samples decreased when exposed to solar light for longer times and the decrease was inversely proportional to sample thicknesses. However, due to the complexity of changes in structural and chemical properties of samples by weathering, different patterns of the activation energy of each sample were obtained for each sample by the estimation study due to the complexity polymer degradation. The results of this study show changes in thermal properties of PP and PP-MWCNT composites by accelerated weathering with thermogravimetric and calorimetric analyses, indicating these analytical techniques are useful to study and understand the polymer degradation by aging in the environment when polymers are disposed during or at the end of their use.Disclaimer and AcknowledgementThe views expressed in this manuscript are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency. This project was supported in part by appointment to the Internship/Research Participation Program at the National Risk Management Research Laboratory, U.S. Environmental Protection Agency, administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and EPA.5. References ADDIN EN.REFLIST [1] C.L. de Dicastillo, del Mar Castro-López, M., López-Vilarińo, J.M., González-Rodríguez, M.V., Immobilization of green tea extract on polypropylene films to control the antixodiant activity in food packaging, Food Research International 53 (2013) 522-528.[2] T.S. Ellis, D'Angelo, J.S., Thermal and mechnical properties of a polypropylene nanocomposite, Journal of Applied Polymer Science 90(6) (2003) 1639-1647.[3] N. Lepot, Van Bael, M.K., Van den Rul, H., D'Haen, J., Peeters, R., Rfanco, J. Mullens, D., Influence of incorporation of ZnO nanoparticles and biaxial orientation on mechanical and oxygen barrier properties of polypropylene films for food packaging applications, Journal of Applied Polymer Science 120 (2011) 1616-1623.[4] V. Vassiliou, Bikiaris, D., Chrissafis, K., Paraskevopoulos, K.M., Staverv, S.Y., Docoslis A., Nanocomposites of isotactic polypropylene with carbon nanoparticles exhibiting enhanced stiffness, thermal stability and gas barrier properites, Composites Science and Technology 68(3-4) (2008) 933-943.[5] W. Chen, Tao, X., Xue, P., Cheng, X., Enhanced mechanical properties and morphological characterizations of poly(vinyl alcohol)-carbon nanotube composite films, Applied Surface Science 252 (2005) 1404-1409.[6] J.Y. Kim, Han, S. I., Hong, S., Effect of Modified carbon nanotube on the properties of aromatic polyester nanocomposites, Polymer 49(15) (2008) 3335-3345.[7] M.L. Manchado, L. Valentini, J. Biagiotti, J. Kenny, Thermal and mechanical properties of single-walled carbon nanotubes–polypropylene composites prepared by melt processing, Carbon 43(7) (2005) 1499-1505.[8] K. Prashantha, J. Soulestin, M. Lacrampe, P. Krawczak, G. Dupin, M. Claes, Masterbatch-based multi-walled carbon nanotube filled polypropylene nanocomposites: Assessment of rheological and mechanical properties, Composites science and technology 69(11) (2009) 1756-1763.[9] H. Zeng, C. Gao, Y. Wang, P.C. Watts, H. Kong, X. Cui, D. Yan, In situ polymerization approach to multiwalled carbon nanotubes-reinforced nylon 1010 composites: mechanical properties and crystallization behavior, Polymer 47(1) (2006) 113-122.[10] J. Du, S. Wang, H. You, X. Zhao, Understanding the toxicity of carbon nanotubes in the environment is crucial to the control of nanomaterials in producing and processing and the assessment of health risk for human: a review, Environmental toxicology and pharmacology 36(2) (2013) 451-462.[11] C.-w. Lam, J.T. James, R. McCluskey, S. Arepalli, R.L. Hunter, A review of carbon nanotube toxicity and assessment of potential occupational and environmental health risks, Critical reviews in toxicology 36(3) (2006) 189-217.[12] Y. Liu, Y. Zhao, B. Sun, C. Chen, Understanding the toxicity of carbon nanotubes, Accounts of Chemical Research 46(3) (2012) 702-713.[13] V. Boddu, P. Redner, Energetic Materials: Thermophysical Properties, Predictions, and Experimental Measurements, CRC Press2010.[14] E. Sahle-Demessie, C. Han, A. Zhao, B. Hahn, H. Grecsek, Interaction of engineered nanomaterials with hydrophobic organic pollutants, Nanotechnology 27(28) (2016) 284003.[15] I. Ghorbel, F. Thominette, P. Spiteri, J. Verdu, Hydrolytic aging of polycarbonate. I. Physical aspects, Journal of applied polymer science 55(1) (1995) 163-171.[16] D. Raghavan, A. Torma, DSC and FTIR Characterization of Biodegradation of Polyethylene, Polymer Engineering & Science 32(6) (1992) 438-442.[17] W. Wohlleben, C. Kingston, J. Carter, E. Sahle-Demessie, S. Vázquez-Campos, B. Acrey, C.-Y. Chen, E. Walton, H. Egenolf, P. Müller, NanoRelease: Pilot interlaboratory comparison of a weathering protocol applied to resilient and labile polymers with and without embedded carbon nanotubes, Carbon 113 (2017) 346-360.[18] T. Nguyen, E.J. Petersen, B. Pellegrin, J.M. Gorham, T. Lam, M. Zhao, L. Sung, Impact of UV irradiation on multiwall carbon nanotubes in nanocomposites: Formation of entangled surface layer and mechanisms of release resistance, Carbon 116 (2017) 191-200.[19] T. Corrales, F. Catalina, C. Peinado, N. Allen, E. Fontan, Photooxidative and thermal degradation of polyethylenes: interrelationship by chemiluminescence, thermal gravimetric analysis and FTIR data, Journal of Photochemistry and Photobiology A: Chemistry 147(3) (2002) 213-224.[20] L. Mandelkern, Characterization of crystalline polymers by Raman spectroscopy and differential scanning calorimetry, Polymer characterization: physical property, spectroscopic, and chromatographic methods (1988) 377-395.[21] C.E. Porter, F.D. Blum, Thermal characterization of PMMA thin films using modulated differential scanning calorimetry, Macromolecules 33(19) (2000) 7016-7020.[22] G. Gentile, V. Ambrogi, P. Cerruti, R. Di Maio, G. Nasti, C. Carfagna, Pros and cons of melt annealing on the properties of MWCNT/polypropylene composites, Polymer Degradation and Stability 110 (2014) 56-64.[23] T. Kashiwagi, E. Grulke, J. Hilding, K. Groth, R. Harris, K. Butler, J. Shields, S. Kharchenko, J. Douglas, Thermal and flammability properties of polypropylene/carbon nanotube nanocomposites, Polymer 45(12) (2004) 4227-4239.[24] K.I. Winey, R.A. Vaia, Polymer nanocomposites, MRS bulletin 32(04) (2007) 314-322.[25] W. Wohlleben, N. Neubauer, Quantitative rates of release from weathered nanocomposites are determined across 5 orders of magnitude by the matrix, modulated by the embedded nanomaterial, NanoImpact 1 (2016) 39-45.[26] AMETEK?, Benchmark Climates, (Retrived February 23, 2017).[27] J.H. Flynn, L.A. Wall, A quick, direct method for the determination of activation energy from thermogravimetric data, Journal of Polymer Science Part C: Polymer Letters 4(5) (1966) 323-328.[28] C. Longo, M. Savaris, M. Zeni, R.N. Brandalise, A.M.C. Grisa, Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment, Materials Research 14(4) (2011) 442-448.[29] S. Mutlur, Thermal Analysis of Composites Using DSC, Advanced Topics in Characterization of Composites (2004) 11-33.[30] A. Van der Wal, J. Mulder, R. Gaymans, Fracture of polypropylene: the effect of crystallinity, Polymer 39(22) (1998) 5477-5481.[31] C. Doyle, Kinetic analysis of thermogravimetric data, Journal of applied polymer science 5(15) (1961) 285-292.[32] S. Vyazovkin, Isoconversional kinetics of thermally stimulated processes, Springer2015.[33] M. Chipara, K. Lozano, A. Hernandez, M. Chipara, TGA analysis of polypropylene–carbon nanofibers composites, Polymer Degradation and Stability 93(4) (2008) 871-876.[34] E. Assouline, A. Lustiger, A. Barber, C. Cooper, E. Klein, E. Wachtel, H. Wagner, Nucleation ability of multiwall carbon nanotubes in polypropylene composites, Journal of Polymer Science Part B: Polymer Physics 41(5) (2003) 520-527.[35] L. Li, B. Li, M.A. Hood, C.Y. Li, Carbon nanotube induced polymer crystallization: The formation of nanohybrid shish–kebabs, Polymer 50(4) (2009) 953-965.[36] L. Audouin, V. Langlois, J. Verdu, J.d. Bruijn, Role of oxygen diffusion in polymer ageing: kinetic and mechanical aspects, Journal of Materials science 29(3) (1994) 569-583.[37] T. Kagiya, S. Nishimoto, Y. Watanabe, M. Kato, Importance of the amorphous fraction of polypropylene in the resistance to radiation-induced oxidative degradation, Polymer degradation and stability 12(3) (1985) 261-275.[38] X.C. Zhang, M.F. Butler, R.E. Cameron, The relationships between morphology, irradiation and the ductile–brittle transition of isotactic polypropylene, Polymer international 48(11) (1999) 1173-1178.[39] F. Gugumus, Effect of temperature on the lifetime of stabilized and unstabilized PP films, Polymer Degradation and Stability 63(1) (1999) 41-52.[40] V. Gupta, L. Drzal, M. Rich, The physical basis of moisture transport in a cured epoxy resin system, Journal of Applied Polymer Science 30(11) (1985) 4467-4493.[41] M. Obadal, R. ?ermák, M. Raab, V. Verney, S. Commereuc, F. Fra?sse, Structure evolution of α-and β-polypropylenes upon UV irradiation: A multiscale comparison, Polymer degradation and stability 88(3) (2005) 532-539.[42] M. Rabello, J. White, The role of physical structure and morphology in the photodegradation behaviour of polypropylene, Polymer Degradation and Stability 56(1) (1997) 55-73.[43] M.A. De Paoli, Degrada??o e estabiliza??o de polímeros, Artliber S?o Paulo2009.[44] A. Brzozowska-Stanuch, S.a. Rabiej, J. Fabia, J. Nowak, Changes in thermal properties of isotactic polypropylene with different additives during aging process, Polimery 59(4) (2014) 302--307.[45] M. Rabello, J. White, Crystallization and melting behaviour of photodegraded polypropylene—I. Chemi-crystallization, Polymer 38(26) (1997) 6379-6387.[46] D.M. Wiles, G. Scott, Polyolefins with controlled environmental degradability, Polymer Degradation and Stability 91(7) (2006) 1581-1592.[47] N. Bumbudsanpharoke, S. Ko, A Study of Thermal Properties of LDPE-Nanoclay Composite Films, Korean Journal of Packaging Science & Technology 21(3) (2015) 107-113.[48] H.M. Pires, L.C. Mendes, S.P. Cestari, V.J.R.R. Pita, Effect of Weathering and Accelerated Photoaging on PET/PC (80/20 wt/wt%) Melt Extruded Blend, Materials Research 18(4) (2015) 763-768.[49] S. Bhateja, Radiation‐induced crystallinity changes in linear polyethylene: Influence of aging, Journal of Applied Polymer Science 28(2) (1983) 861-872.[50] S. Bhateja, E. Andrews, S. Yarbrough, Radiation induced crystallinity changes in linear polyethylenes: long term aging effects, Polymer journal 21(9) (1989) 739-750.[51] O. Gal, D. Kostoski, D. Babi?, V. Stannett, DSC melting behavior of irradiated low density polyethylenes containing antioxidants, International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry 28(3) (1986) 259-267.[52] F. Carrasco, P. Pages, S. Pascual, X. Colom, Artificial aging of high-density polyethylene by ultraviolet irradiation, European polymer journal 37(7) (2001) 1457-1464.[53] E.V. Bystritskaya, T.V. Monakhova, V.B. Ivanov, TGA application for optimising the accelerated aging conditions and predictions of thermal aging of rubber, Polymer testing 32(2) (2013) 197-201.[54] J.D. Peterson, S. Vyazovkin, C.A. Wight, Kinetics of the thermal and thermo-oxidative degradation of polystyrene, polyethylene and poly (propylene), Macromolecular Chemistry and Physics 202(6) (2001) 775-784.[55] G. Chigwada, E. Kandare, D. Wang, S. Majoni, D. Mlambo, C.A. Wilkie, J.M. Hossenlopp, Thermal stability and degradation kinetics of polystyrene/organically-modified montmorillonite nanocomposites, Journal of nanoscience and nanotechnology 8(4) (2008) 1927-1936. ................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.