The role of rotor speed on the void fraction and relative density of EVA/NRFoam

Rubbery foams have attractted many industerial application based on their specific strength, lowweight, outstanding impact strength, electrical insulation and etc. Ethylene vinyl acetate (EVA) is acommon material for foam manufacture due to its unique resistance to most chemicals such asoxygen, ozone, UV-radiation and abrasion. The cell of EVA foam collapse because of low meltviscosity against the pressure imposed on the cell walls during expansion step in foaming process.Natural rubber (NR) can be successfully blended with EVA to improve its dimensional stability,resilience, tensile strength, and tear strength. In this study, the optimal mixing speed determined toachieve the desired physical and mechanical properties for EVA/NR foam. EVA/NR foams weremanufactured by melt mixing in an internal mixer and then foaming process was performed bycompression molding. The effect of different mixing speeds (۰۴, ۰۴, ۰۴, ۱۴۴, ۱۲۴ rpm) on void fractionproperties and relative density was investigated. The analysis shows that EVA/NR foam made at aspeed of ۰۴ rpm improves the relative density about %۵۱ and ۰۰۴ volume fraction less than othersamples.

کلیدواژه ها:

foam ، ethylene vinyl acetate ، natural rubber ، void fraction ، relative density