Improved mechanical and rheological properties of recycled polyethylene by acrylic acid-assisted melt grafting of glycidyl methacrylate

The use of glycidyl methacrylate (GMA) and acrylic acid (AAc) as grafting monomers to improve the mechanical properties, particularly tensile strength, of recycled polyethylene (R-PE) is reported in this study. The AAc monomer was implemented to improve the stability of radical chains which could undergo GMA grafting. When the content of GMA and AAc was 1.2% and 0.6%, respectively, the tensile strength increased from 17.26 to 29.3 MPa, the elongation at break increased from 107% to 647%, and the melt index decreased from 3.42 to 0.97 g/10 min. The sensitivity of the dynamic behaviour of R-PE-g-(AAc-co-GMA) to temperature was also reduced relative to R-PE. Differential scanning calorimetry (DSC) results showed that the melting temperature was increased and the crystallisation temperature of R-PE-g-(AAc-co-GMA) was reduced. The fracture morphology of the samples was also shown by scanning electron microscope (SEM) observations to transition from brittle fracture to ductile fracture upon undergoing the grafting process.