Weathering effects on composites of recycled low density polyethylene with fine talc

Abstract

The main problems in post-consumer plastics recycling are due to the degradation undergone lifetime and during process steps. Generally, the fillers have been used to enhance the mechanical properties of recycled polymers. However, it is still unclear if environmental factors, such as temperature, sunlight, oxidation and moisture would cause any loss or compromise the mechanical integrity of the composites. In this work, test specimens of recycled low density polyethylene (LDPE) reinforced with fine talc were produced through three step processes; 1) mixed together by using a twin screw extruder; 2) granulated with a pelletiser; and 3) subjected to injection moulder to produce standard sized test samples. These samples were then exposed to the UV radiation in the accelerate weathering chamber for different ageing time. The mechanical properties of the samples were characterised using by Instron 5543 universal tester with a maximum load capacity of 1KN. Data obtained in this study reveals that there was significant decreased in the tensile strength with respect to the length of the exposure time; however insignificant effects were observed for other mechanical properties. It was also observed that unreinforced LDPE tends to ageing at a higher rate relative to reinforced LDPE. The changes in mechanical properties were related with the chemical processes, which measured through the carbonyl index profile obtained from FTIR. The damage of samples’ surface affected by UV was determined by SEM.