The interaction of delignification and fiber characteristics on the mechanical properties of old corrugated container fiber/polypropylene composite

Abstract

The effect of fiber characteristics from old corrugated container (OCC) paper on the strength properties of OCC/polypropylene composites was evaluated. Fibers with different contents of lignin (2.8%, 3.8%, 5.3%, and 7%) were produced using soda pulping. Wettability, tear, and tensile strength of the fibers were measured as the indication factors to assess the strength of reinforcing component in the composites. The weight portions of the OCC fibers, polypropylene, and maleic anhydride-grafted polypropylene (MAPP) were selected at 20%, 77%, and 3% of the total weight of the composite, respectively. The composite compounds were formed using a counter-rotating twin screw extruder, and the specimens were made in an injection molding machine. The interaction of fiber characteristics and fiber lignin content on the mechanical properties of composite was investigated. The results revealed that with lower fiber lignin content, both flexural and tensile properties were increased. Consequently, by forming better fiber dispersion and by reducing stress regions in the composite, impact strength was also improved. Lower lignin content resulted in better mechanical properties than fiber characteristics.