Thesis (M.Eng.)--Chulalongkorn University, 2009

The effects of dicumylperoxide crosslinking agent loading and modifiled azodicarbonamide with zinc oxide chemical blowing agent loading, ratio of LDPE/EVA at 70/30 and 80/20 wt/wt and vinyl acetate content in ethylene vinyl acetate copolymer at 18%wtVA and 28%wtVA on the physical and mechanical properties of LDPE/EVA blend foams were studied. LDPE were mixed with EVA and additives using twin-screw extruder. Polymer blend foam were produced by two-stage process; pre-foamed sheet were made by compression molder and expanded in hot air oven. The experimental results showed that increasing of crosslinking agent loading led to higher degree of crosslinking and lower foam density. However, the increasing of crosslinking agent loading together with increasing of chemical blowing agent loading led to higher foam density due to too high degree of crossling for the amount of chemical blowing agent used. Overall, the mechanical properties of obtained foams increased with increasing foam densities. Lower the foam density, softer and more flexible the foams became.