Green-composites produced from waste residue in pulp and paper industry: A sustainable way to manage industrial wastes

In order to achieve an effective re-utilization of pulp and paper industry waste (PIW), PIW was recycled and used as a filler to prepare green-composites based on linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and ultrahigh molecular weight polyethylene (UHMWPE) through an extrusion and injection molding in this study. The resultant green-composites were characterized by infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetry, tension, dynamic mechanical analysis, and micro mechanism. The results showed that the addition of PIW promoted crystallization and improved the thermal stability of LLDPE, HDPE, and UHMWPE. Moreover, the tensile properties of LLDPE, HDPE, and UHMWPE were significantly improved as a result of PIW addition. The best tensile strength of 26.73 MPa and Young’s modulus of 1.82 GPa were obtained in PIW/HDPE composites. The dynamic mechanical analysis revealed that the addition of PIW increased the rigidity and elasticity of LLDPE, HDPE, and UHMWPE. The utilization of hazardous PIW in this study not only avoids secondary pollution but also generates green-composites with better thermal and mechanical properties.