Properties of Recycled Plastics from HDPE Drinking Water Bottles

Abstract

The growing amount of plastic bottles have caused plastic waste problem in Thailand and elsewhere. In this paper the recycling of drinking water bottles made of HDPE was studied. Collected waste bottles were ground to small pieces and then mixed with virgin HDPE resin at the composition of
0, 20, 25, 40, and 50% recycled plastics. The effect of adding 0, 10, 20 and 30% (w/w) of calcium carbonate as plastic filler was also studied. The mixed compound was injection molded into dumbbell – shaped testing samples and tested for density, tensile strength and elongation. The result showed that increased recycled plastics significantly reduced density and tensile strength but increased elongation of tested samples. Addition of calcium carbonate also significantly decreased both tensile strength and elongation. The chosen quantity of recycled plastics in compounded mixture was 20% and calcium carbonate content of 10%. The recycled HDPE was utilized by injection molding into flowerpots or multi-purpose trays.