ABSTRACT

According to the American Society for Testing and Materials standard ASTM D-883, a ller is a relatively inert material added to a plastic to modify its strength, permanence, working properties, or other qualities, or to lower costs, while a reinforced plastic is one with some strength properties greatly superior to those of the base resin resulting from the presence of high-strength llers

embedded in the composition. The word extender is sometimes used for llers. Also, the notion that llers simply “ll” without adding some needed property is not always appropriate. Some llers are more expensive than the polymer resin and do contribute positively to the overall properties.