A study on the mechanincal properties of the combination of glass fibre and mineral fillers for reinforcing recycled low density polyethylene

Abstract

Plastic lumber is manufactured by using thermoplastic reinforced with fillers. The disadvantages of plastic lumber compared to timber are lower stiffness and strength. To improve the mechanical properties of these products, manufacturers normally add fillers as reinforcement to the polymer matrix. In this study, the effects of combinations of glass fibre and mineral fillers, such as calcium carbonate (CaCO3) and talc on the mechanical properties of recycled low density polyethylene (LDPE) were investigated. The amount of filler was fixed at 30 wt%. The plastics and fillers were initially mixed together using a twin screw extruder and then granulated using a pelletiser. The granules were fed into an injection moulder to produce standard sized test samples. The flexural and tensile tests were performed using an INSTRON 5543 universal tester with a maximum load capacity of 1kN. The mechanical properties of the recycled LDPE were found to increase with the addition of the fillers. In particular, the addition of fillers to recycled LDPE increased its flexural strength by 40-140% and modulus by 60-250% depending on the formulation. Similarly, the tensile strength was found to increase by 20-50% and the modulus by 70- 300%. Talc-glass fibre composites exhibited higher tensile and flexural properties compared to those of CaCO3-glass fibre composites. The most crucial finding in this study is that partial substitution of 3mm glass fibre with 10% Talc T45B has shown comparable mechanical properties to the 30% 3 mm GF composites.