Yupeng Su,Kehui Han,Martin Hoch,Jie Mao,Xinyan Shi
Moisture crosslinking would be a good substitution to cure ethylene-vinyl acetate-glycidyl methacrylate rubber (EVM-GMA) due to the characteristics of low cost and environmental friendliness. Our previous study found amino silane grafted onto EVM-GMA with low degree due to the low epoxy group content in rubber matrix. Consequently, the moisture crosslinking density of rubber compound is low. So, it is necessary to find an effective method to improve the moisture crosslinking density of EVM-GMA. In this paper, EVM-GMA grafted with γ-aminopropyltriethoxysilane and maleic anhydride (EVM-GMA-g-APTES/MAH) composites were prepared by melt blending, and then the moisture crosslinking of composites was achieved in a 90°C water bath with the aid of catalyst dibutyltin dilaurate (DBTL). The grafting of MAH onto the EVM-GMA molecular chain and its reaction with amino silane were confirmed by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, the moisture crosslinking density of the samples before and after grafting MAH was compared. The results indicated that the moisture crosslinking density of the grafted MAH was higher than that of the unmodified rubber, thus achieving better overall mechanical properties. Therefore, grafting MAH was a feasible way to improve the moisture crosslinking density of EVM-GMA with the existence of silane.
Zhenyin Guo,Qingshan Yang,Songhan Wan,Kang Zhu,Hongtao Li,Chen Peng,Xianru He
Ethylene-vinyl acetate (EVM) rubber exhibits relatively poor elasticity, restricting its wide application. The effects of flexible vulcanization agents, ethylene glycol dimethacrylate (EGDMA) and tripropanediol diacrylate (TPGDA), on the mechanical properties and vulcanization characteristics of EVM were studied. At a 3 phr dosage, EGDMA and TPGDA increased elongation at break by 23.5% and 37.0%, respectively, while improving tension set recovery. These agents extended scorch time and reduced optimum vulcanization time. Vulcanization kinetics analysis demonstrated that these two agents shortened vulcanization time, improved production efficiency, and reduced initial reaction temperature (10°C–20°C) and activation energy (7–21 kJ/mol). This study offers a low-cost and simple method to enhance the elasticity and vulcanization properties of EVM and other rubber materials.
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