Improved dimensional stability of styrene butadiene rubber/ethylene vinyl acetate composite foams with skeleton support structure based on alternately cross-linking process

Styrene butadiene rubber (SBR) foam materials are utilized with potential to combine marvelous compression set with mechanical properties, but its dimensional stability cannot meet actual production. In this paper, ethylene vinyl acetate (EVA) with a certain crystallinity is introduced in the SBR foams matrix based on the alternately cross-linking process to build a skeleton support structure. SBR/EVA foams with lower shrinkages and excellent dimensional stabilities are obtained. SBR unit radicals can react with EVA copolymer unit radicals, which has been confirmed by the simulation calculation. Alternately cross-linking process and its influence on the dimensional stability of SBR/EVA foams have also been demonstrated by FTIR, NMR, TGA and DSC. The results demonstrate that the post shrinkage of SBR/EVA foams is reduced by 70% compared with that of the SBR foams and EVA plays the role of support skeleton.