Effect of waste fillers addition on properties of high-density polyethylene composites: mechanical properties, burning rate, and water absorption

Generally, fillers are added in thermoplastic polymers to enhance their mechanical properties, reduces cost, and improve appearance of the composites. In this paper, high-density polyethylene (HDPE) was compounded with different waste fillers such as silica, kaolin, calcium carbonate, and fly ash with an aim to compare the composite performance and effects of different filler loading. Tensile test, impact test, burning test, and water absorption were used to characterize the HDPE composites. Results show that addition of fillers in HDPE improved the tensile modulus, reduced 14% of the burning rate, and increased water absorption over time, compared to unfilled HDPE. However, tensile strength, impact strength, and elongation at break reduced by 30-50%, 50%, and 98% compared to the neat HDPE, respectively. Addition of calcium carbonate in HDPE shows the best fire retardant, the highest tensile strength, and the longest elongation at break as compared to composites with silica, fly ash, and kaolin.