Physico-mechanical properties of paper sludge-thermoplastic polymer composites

This study investigates the effect of paper sludge's mixing ratio and the types and concentrations of coupling agents on the physical and mechanical properties of paper sludge-thermoplastic polymer composites. In the experiment, four levels of mixing ratios of paper sludge to thermoplastic polymer (10:90, 20:80, 30:70 and 40:60) and three levels of coupling agent (Epolene G-3003™) content (1, 3, and 5wt.%) were designed to discuss the physical and mechanical properties of composite. Composite density, as expected, increased but melt flow index decreased when the paper sludge content increased. Thickness swelling and water absorption of composites was slightly improved by the addition of paper sludge compared with control specimens. Tensile properties of composites significantly increased as the mixing ratio of paper sludge increased. Especially, tensile modulus improved with the increase of paper sludge content. Flexural strength and modulus showed similar trends to that of the tensile properties. Notched and unnotched Izod impact strengths lowered by the addition of paper sludge. With the addition of coupling agent, G-3003™, tensile and flexural properties improved considerably compared with control specimens (without any coupling agent). Epolene G-3003™, with high molecular weight, was effective in the improvement of the composites' tensile and flexural properties.