Plastics are man-made materials that can be shaped into almost any form. They are one of the most useful materials ever created. Our homes, schools, and businesses are filled with plastic products. Engineers have developed plastics that are as rigid as steel or as soft as cotton. They can make plastics that are any color of the rainbow--or as clear and colorless as crystal. Plastics can be rubbery or rigid, and they can be shaped into an endless variety of objects, ranging from automobile fenders to soft fabrics.

Automakers commonly use plastic bumpers, fenders, and wheel covers in their products. In some cars, the entire body is made of plastics. Plastic auto parts do not rust, nor do they dent as easily as metal ones. Plastic auto parts are easier and often less expensive to repair. Replacing metal parts with plastic ones also reduces the weight of a vehicle, resulting in more efficient fuel use. Surgeons mend broken bones with plastic parts rather than metal ones because the plastics are less likely to trigger a harmful reaction.

The textile industry uses plastics to replace such natural fibers as cotton, ramie, silk, and wool. Plastic fibers may have such qualities as strength, durability, and resistance to stains and wrinkling. Some plastic fibers are tough enough to be used for automobile safety belts or bulletproof vests. Others are delicate enough to be made into sheer hosiery.

Plastics have replaced paper in many packaging applications. Plastic-foam packing materials provide more protection for boxed products than crushed paper does. Many products are packed in foamed plastic inserts that fit the shape of the item exactly. Plastic wraps preserve foods longer than paper wraps can. Plastic bottles are also shatterproof, and they have replaced glass ones in packaging such products as milk, ketchup, household cleaners, and many other foods and household goods. Plastic bottles also weigh much less than glass ones.

Plastics are used in many ways that would not be possible for other materials. They have many medical applications because they are not harmful to the body and can be formed into any shape. Parts made from plastics can replace damaged hip, knee, and finger joints. Sometimes, plastic parts are used to replace faulty heart valves.

Excerpt from the "Plastics" article, The World Book Encyclopedia © 1999