Weld line behaviour of exfoliated and toughened polypropylene layered silica nanocomposites

Abstract

Exfoliated and toughened polypropylene nanocomposites prepared by an introduction of a rubber in the form of compatibilizer toughener: ethylene propylene diene based rubber grafted with maleic anhydride (EPDM-g-MAH) were studied in terms of weld line properties and morphology. Effects of addition of rubber and nanolayer on weld line strength under tensile loading condition of polypropylene matrix were investigated. Data showed that in the absence of either EPDM or nanolayers, a sharp decrease in weld line strength cannot be avoided whereas in the presence of each in optimum ratio, the drastic increase in both toughness and weld line strength values can be easily reached. The beneficial effect is believed to come from the selective placing of nanolayers around the rubber droplets and making them smaller in size which contributes to diffused weld line regions with high mechanical strength.