Preparation, Characterization, and Properties of Pre-irradiated Linear Low-Density Polyethylene Grafted Itaconic Anhydride by Reactive Extrusion

Abstract

Graft copolymerization of itaconic anhydride (IAH) onto pre-irradiated linear low-density polyethylene (LLDPE) was carried out in a twin-screw extruder. FT-IR was used to characterize the formation of graft copolymer and the percentage of grafted IAH was determined. The effects of monomer concentration and screw speed on degree of grafting were studied. The thermal behavior of LLDPE-g-IAH was investigated using differential scanning calorimetry. The crystallization temperature (Tc) of LLDPE-g-IAH increased compared of that of neat LLDPE. The tensile properties of the graft copolymer were determined. No obvious changes could be found for the tensile strength, elongation at break, and Young's modulus of the graft copolymer compared to that of neat LLDPE. It was found that contact angles of the water on the film surface of LLDPE-g-IAH decreased with increasing content of IAH in LLDPE-g-IAH. Adhesion between the graft copolymer and stainless steel was investigated. Outstanding peel strength was obtained by introducing polar groups onto the LLDPE molecular chains.