Role of blend phase ratio in controlling morphology, compressive, and recovery behavior of low‐density polyethylene/ethylene‐vinyl acetate foams

Abstract

AbstractThis work presents a detailed study on the influence of blend phase ratio upon the morphology, crystallinity, mechanical and viscoelastic properties of cross‐linked foams based on blends of low‐density polyethylene (LDPE) and ethylene‐vinyl acetate copolymer (EVA). Non‐isothermal foaming is carried out via melt compression molding using dicumyl peroxide and azodicarbonamide as crosslinking and foaming agents, respectively. Rheo‐mechanical spectrometer characterization reveals faster crosslinking for EVA, leading to higher rate of melt viscosity increase for EVA‐rich blends during heating. This results in the formation of foams with higher cell density and gel content than LDPE‐rich foams. Compressive stress–strain behavior and viscoelastic hysteresis of the LDPE‐rich foams are governed by the degree of crystallinity and cell density, whereas for the EVA‐rich foams cell density and gel content are dominant. Increasing the crosslink density results in enhanced compressive behavior with excellent recovery of stress to 60% strain during four compression cycles.