Effects of Chemical Modification of Paper Sludge Filled Polypropylene (PP)/Ethylene Propylene Diene Terpolymer (EPDM) Composites

The effects of surface treatment of paper sludge (PS) with acrylic acid (esterification) and acetic acid (acetylation) on torque, stabilization torque, mechanical properties, water absorption, morphology, and thermal properties of PP/EPDM/PS composites were studied. It was found that esterified and acetylated composites exhibit higher stabilization torque than untreated composites. The esterification and acetylation treatment have improved the tensile strength, elongation at break, and Young's modulus but have reduced the water absorption of composites. The scanning electron microscopy (SEM) study of the tensile fracture surface of the esterified and acetylated composites indicates that the presence of acrylic acid and acetic acid increased the interfacial interaction between paper sludge and PP/EPDM matrix. The esterification and acetylation treatment also increase the thermal stability and crystallization of PP/EPDM/PS composites. It was found that paper sludge acts as a nucleation agent in the presence of acrylic acid and acetic acid.