Mechanical hysteresis, interface and filler–filler structural breakdowns in ethylene vinyl acetate organoclay composites internally lubricated via radiolytically degraded PTFE microparticles

Abstract

ABSTRACTInclusion of two or more distinct fillers (hybrid fillers) in a matrix is envisaged to entail synergetic advantages. This study reports synthesis and property evaluation of a novel hybrid filler‐based polymer composite containing two types of fillers with distinct attributes namely mechanical reinforcement and internal lubrication. Poly(tetrafluoroethylene) micro‐particles (PTFEMP) were synthesized via radiolytic‐mechanical degradation and used as an internal lubricant for organoclay (OC) reinforced ethylene vinyl acetate (EVA) matrix. Mechanical hysteresis, nonlinear and linear small amplitude oscillatory shear rheology, morphology, small angle X‐ray scattering (SAXS), dynamic coefficient of friction (DCoF), surface wetting and thermoxidative stability of binary and ternary composites were investigated. In EVA/OC composites, PTFEMP acted as an internal lubricant and reduced DCoF in a volume fraction‐dependent fashion. OC and PTFEMP both increased the mechanical hysteresis of EVA; though the magnitude of hysteresis was much less in PTFEMP. Intriguingly, PTFEMP reduced mechanical hysteresis of EVA/OC composites that is work done during loading and unloading stress–strain cycles was considerably reduced with the inclusion of PTFEMP in EVA/OC composites. SAXS results revealed mass fractals and the presence of an interfacial layer in EVA/OC composites but not in EVA/PTFEMP composites. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 509–519