Plastics and Polymers Science Fair Projects : Using Hair ...

[Pages:30]Madeline Goodstein

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Chemistr y! BEST

SCIENCE PROJECTS

Using Hair Gel, Soda Bottles, and

Slimy Stuff

Madeline Goodstein

Acknowledgments

The author thanks Valerie A. Wilcox, Executive Director of the National Plastics Center and Museum, for arranging a guided tour, and Anne-Marie Arnold, In-House Education Director, for giving the tour of the museum.

Copyright ? 2004 by Madeline Goodstein

All rights reserved.

No part of this book may be reproduced by any means without the written permission of the publisher.

Library of Congress Cataloging-in-Publication Data

Goodstein, Madeline P. Plastics and polymers science fair projects using hair gel, soda bottles,

and slimy stuff / Madeline Goodstein. v. cm. -- (Chemistry! best science projects)

Includes index. Contents: What a polymer is -- Some properties of polymers -- Testing plastics. ISBN 0-7660-2123-8 (hardcover) 1. Polymers--Experiments--Juvenile literature. 2. Plastics--Experiments--Juvenile literature. [1. Polymers--Experiments. 2. Plastics--Experiments. 3. Experiments.] I. Title. II. Series. QD381.3.G66 2004 507'.8--dc22

2003012825

Printed in the United States of America

10 9 8 7 6 5 4 3 2 1

To Our Readers: We have done our best to make sure all Internet Addresses in this book were active and appropriate when we went to press. However, the author and the publisher have no control over and assume no liability for the material available on those Internet sites or on other Web sites they may link to. Any comments or suggestions can be sent by e-mail to comments@ or to the address on the back cover.

Illustration Credits: Tom LaBaff

Cover Photo: ? Corel Corporation (background), ? Hemera Technologies, Inc., 1997?2000.

Plastics and Polymers Are All Around Us . . . . . . . . . . . . . . . . . . . 5

1.1 Making a Polymer . . . . . . . . . . . . . . . . . 15 1.2 A Simple Model of a Polymer . . . . . . . . 20 1.3 Arrangement of Carbon Bonds

in Space . . . . . . . . . . . . . . . . . . . . . . . . 25 1.4 Making Slime: Cross-Linking . . . . . . . . . 30 1.5 A Model Problem . . . . . . . . . . . . . . . . . 36

Some Properties of Polymers . . . . . . . . . . 40

2.1 Polymers That Melt, Polymers That Burn . . . . . . . . . . . . . . . . . . . . . . . 42

2.2 Making and Shaping Thermosetting Plastic. . . . . . . . . . . . . . . 45

2.3 Some Polymers Like Water. . . . . . . . . . . 49 2.4 Styrofoam: A Polymer That

Does Not Like Water . . . . . . . . . . . . . . . 56 2.5 Fabrics That Like Water,

Fabrics That Don't. . . . . . . . . . . . . . . . . 63 2.6 Permeability to Water . . . . . . . . . . . . . . . 65

Testing Plastics . . . . . . . . . . . . . . . . . . . . . . 70

3.1 Identification and Separation of Plastics for Recycling . . . . . . . . . . . . . . . 72

3.2 Measuring the Stretch . . . . . . . . . . . . . . 82

3.3 Shrink Wraps. . . . . . . . . . . . . . . . . . . . . 86 3.4 Heat Insulation . . . . . . . . . . . . . . . . . . . 89

The Mysterious Case of Natural Rubber . . . . . . . . . . . . . . . . . . . . . . 94

4.1 Making a Plastic Fiber . . . . . . . . . . . . . . 97 4.2 Are Plastic Food Containers

Safe to Use in a Microwave? . . . . . . . . . 101 4.3 Does Polystyrene Melt in

Boiling Water? . . . . . . . . . . . . . . . . . . . . 105 4.4 Elastomers . . . . . . . . . . . . . . . . . . . . . . . 110 4.5 Chewing Elastic for Fun . . . . . . . . . . . . . 116

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Appendix A: Some Common Synthetic Polymers, Their Monomers, and Applications . . . . . . . . . . 122

Appendix B: Recycling Resin Identification Codes . . . . . . . . . . . . . . . . . . 123

Further Reading. . . . . . . . . . . . . . . . . . . . . . 124

Internet Addresses . . . . . . . . . . . . . . . . . . . 125

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Chapter

W hat comes to mind when you think of plastics? How about wash-and-wear clothing that doesn't need ironing; bicycle and motorcycle helmets that save lives; thin, clear wrap to keep food moist and safe; automobile tires good for sixty thousand miles; bullet-proof vests; picnic cups that keep hot drinks hot and cold drinks cold; glue so "instant" that you have to be careful not to glue your fingers together; CDs and cassettes with your favorite music; carpets where food spills can be washed right off; and pot handles, quick-drying paints, chair and couch upholstery, airplane windows, tabletops and countertops, foam mattresses, patio chairs, boat hulls, vinyl floor tiles, dishes, toys, bathtub caulk, plumbing pipes, fences,

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Plastics and Polymers Science Fair Projects

insulation, surgical gowns, computer chips, and much more. As you can see, plastics are used for many things in our lives.

How do you know when something is plastic? Often, you can tell that something is plastic when you lift it. This is because many plastics are lightweight. The feel of the plastic is often another way to tell. A chunk of plastic feels firm yet not as hard as metal. Plastic wraps have their own special properties. They are soft and flexible. A plastic wrap sticks to itself and can be stretched.

Weight, feel, and stretchability are all special characteristics of plastics that are unlike those of other materials. Why do plastics have these properties? The answers to this question will be explored in the experiments in this book.

WHAT ARE PLASTICS AND POLYMERS?

What is a plastic? What makes it different from other materials? The answer is a chemical one. All plastics are made of a

special kind of chemical. This special kind of chemical is called a polymer. Plastics are all made principally of polymers.

What is a polymer? A polymer is a very large molecule. A polymer molecule may be thousands or even millions of times larger than nonpolymer molecules. For any substance, the smallest bit of matter that can be identified as that substance is called a molecule. An example of a molecule that we all know is the water molecule, H2O. The

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