Microstructural correlations to micromechanical properties of polyamide-6/low density polyethylene-grafted-maleic anhydrideanoclay ternary nanocomposites

摘要

Ternary nanocomposites were fabricated based on an optimized impact modified polyamide-6 (PA-6)/ low density polyethylene grafted maleic anhydride (LDPE-g-MA) blend composition with varied concen tration (~0-6 wt.%) of organoclay, Cloisite 30B™. The microstructural attributes such as state of interca lation/exfoliation/crystalline organization and fractured surface topography of the nanocomposites by using electron microscopic and X-ray diffraction techniques. The X-ray diffraction studies have revealed that the crystallinity of the nanocomposites remained inappreciably affected. Dynamic mechanical anal ysis revealed an increase in Tg of the nanocomposites relative to the neat PA-6 and the optimized PA-6/ LDPE-g-MA blend matrix indicating the reinforcement effects/mechanical restrictions imposed by the nanoclay layers to the polymer chain mobility. The quasi-static mechanical response and micromechan ics aspects concerning interfacial effects and stress-transfer efficiency of the nanocomposites using Halpin-Tsai, Hui-Shia, Takayanagi and Pukanszky models have been investigated. Micromechanical anal ysis based on minimalistic assumptions revealed interphase-thickness reduction at higher nanoclay con tent with a correspondence to the reduction in reinforcement-efficiency. Scanning electron microscopy of the cryo-fractured xylene-etched nanocomposite surfaces have indicated a nanoclay content dependent transition from homogeneous to inhomogeneous deformation assisted by the formation of random microfibril-like interconnected networks.