<P> Typical additives include: </P> <P> Polymer stabilizers prolong the lifetime of the polymer by suppressing degradation that results from UV - light, oxidation, and other phenomena . Typical stabilizers thus absorb UV light or function as antioxidants . </P> <P> Many plastics contain fillers, to improve performance or reduce production costs . Typically fillers are mineral in origin, e.g., chalk . Other fillers include: starch, cellulose, wood flour, ivory dust and zinc oxide . </P> <Ul> <Li> most fillers are relatively inert and inexpensive materials, make the product cheaper by weight . </Li> <Li> stabilizing additives include fire retardants, to lower the flammability of the material . </Li> <Li> some fillers are more chemically active and are called: reinforcing agents . </Li> </Ul>

When did cars start being made of plastic