FORMULATION OF THE MODEL FOR OPTIMAL PROPORTION OF FILLER IN POLYMER FOR ABRASIVE WEAR-RESISTANCE

To date the optimal proportions of fillers in polymer composites for strength and abrasive wear resistance have been obtained by the method of trial and error. In this paper, a theoretical model for the optimal filler proportion based on the random packing model of particles in polymers is presented. A computer program based on this model was written. Using this program and the data on filler particle size distribution, the density of filler and polymer, and the distance between particles of filler in the critical packing state, the proportion of filler in the polymer composite was calculated. It was found that a small variation in particle size distribution did not significantly affect the calculated results. The model was tested for strength and abrasive wear resistance. For this purpose, nylon 11 composites with two inorganic fillers, namely copper and iron, were prepared by compression molding. Together with tensile strength and hardness measurements, the composites were tested for abrasive wear resistance in a pin-on-disk set-up. There was an excellent agreement between the optimal proportions obtained by calculation and those determined by actual experiments.