Enhancement of mechanical properties of waste-sourced biocomposites through peroxide induced crosslinking

The enhancement of mechanical performance of waste-sourced biocomposites through peroxide induced crosslinking was investigated in order to expand their range of applications. Biocomposites containing 25 to 35 wt% of residual Kraft-pulp cellulose fibers, 1.5 wt% of a selected maleic-anhydride-modified polyethylene coupling agent and a 60/40 (w/w) of recycled agricultural plastic/post-consumer plastic blend were compounded in an extrusion-compounding pilot-plant. Changes in the blend structure due to the presence of the organic peroxide used were studied by spectroscopy and thermal analysis. It was found that the addition of extremely low amounts of peroxide (0.025–0.050 wt%) results in remarkable improvements in stiffness, strength and toughness of biocomposites, without compromising processability. Thus, their tensile strength and energy at break increased up to 89.4% and 138%, respectively, with regard to uncrosslinked biocomposites. Scanning electron microscopy revealed an improvement of the fiber–matrix adhesion due to the treatment with the peroxide.