According to zhe American Society for Testing and Materials standard ASTM D 883,a filler is a relatively inert material added to a plasticd to modify its strength, permanence,working properties,or other qualities or to lower costs,while a reinforced plastics is one with some strength properties greatly superior to those of the base resin resulting from the presence of high-strength filers embedded in the composition. According to ASTM,plastic laminates are the most common and strongest type of reinforced plastics.