THE INFLUENCE OF SOFT FILLER CHARACTERISTICS AND FUSION LEVEL ON THE IMPACT STRENGTH OF POLY(VINYL CHLORIDE)

The impact strength of rigid PVC filled with scrap dust from the buffi ng process in sports shoe sole manufacture has been investigated. Dust from outsoles, midsoles, laminated shoe bottoms, and laminate dust wh ich had been separated by sieving into various particle sizes, were mi xed into PVC at various levels of addition. The effects of scrap dust type, sieving, level of addition, dust particle size and aspect ratio on the impact strength of the compounds are reported. The influence of PVC fusion level on the impact strength of the composite containing m idsole dust is also reported. An optimum PVC fusion level of 40% was f ound to exist for the latter composite. The results showed that the im pact behaviour was dependent on scrap type and level of addition but w as independent of dust particle size and aspect ratio. Sieving the scr ap dust prior to mixing did not improve the final dispersion level or impact strength. A 20% loading of midsole scrap dust in PVC gave a sup erior Charpy notched impact strength at a lower cost than a 5% loading of a commercial ABS impact modifier.