The Effect of Compatibilizer and Coupling Agent on the Properties of Paper Sludge Filled Polypropylene (PP)/Ethylene Propylene Diene Terpolymer (EPDM) Composites

Paper sludge-polypropylene (PP)–ethylene propylene diene terpolymer (EPDM) composites were developed in this study. The paper sludge was used as a filler in PP/EPDM blends, and maleic anhydride-grafted PP (MAPP) and LICA were used as a compatibilizer and a coupling agent, respectively. The mechanical properties, thermal behavior, water absorption, morphology, and the compatibilization mechanism of the composites were investigated. The better mechanical properties (e.g., tensile strength and tensile modulus) and lower water absorption with the addition of both compatibilizer and coupling agent were due to the improvements in the wetting of filler surface and better filler matrix interaction of composites as evidenced from scanning electron microscopy studies. It was found that paper sludge acted as a nucleation agent with the presence of MAPP and LICA. The addition MAPP and LICA also increased the crystallization of PP and thermal stability of PP/EPDM/PS composites. The interaction between MAPP and LICA with paper sludge was confirmed with FTIR.