Morphological analysis of polyethylene foams with post-use material incorporated

This study investigated the morphology of low-density polyethylene ( LDPE) foams with post-use polyethylene (p-PE) incorporated. Samples manufactured using compression molding were analyzed through scanning electron microscopy. Micrographs were treated using the software Image Tool for Windows, version 3.00. This allowed the determination of cell size ( 0 - 2500 mu m) and cell area ( 0 - 1500.10(3) mu m(2)) distributions. The research found that all compositions with p-PE material incorporated ( 15, 30, 40, 50 and 70% w/w) had similar morphologies, except the composition with 70% of p-PE, which gave a more significant increase in the amount of smaller cells. In comparison to samples with virgin LDPE only, all samples with p-PE showed an increase in cells with smaller areas (< 60 mu m) and smaller diameters (< 850 mu m(2)), especially those with 70% p-PE. This finding may be explained by the smaller melt flow index of the p-PE (0.60 g.min(-1)) in relation to LDPE ( 1.74 g. min(-1)), which hinders cell growth. The addition up to 70%, of p-PE in formulations which contain 5% of azodicarbonamide leads to PE foams with ideal density ranges for use as packaging ( 30 to 70 kg. m(3)).