Qinghong Zhang,Gongliang Wang,Xinlong Wen,Martin Hoch,Jie Mao,Xinyan Shi
Ethylene-vinyl acetate rubber (EVM) is commonly crosslinked by peroxides due to its saturated main chain. Nevertheless, it is usually accompanied by side reactions to bring unexpected bubbles in products. So, it is necessary to find an alternative and environment friendly crosslinking for EVM. Herein, a silane of γ -aminopropyltriethoxysilane (APTES) containing amino groups was adopted as monomer to graft on the matrix of a modified polymer of EVM named ethylene-vinyl acetate-glycidyl methacrylate terpolymer elastomer (EVM-GMA). EVM-GMA-g-APTES was prepared through melt blending followed by the moisture crosslinking, which was achieved in a 90 °C water bath with the aid of catalyst dibutyltin dilaurate (DBTL). It was found that the characteristic absorption peak belonging to the Si–O–C bond of the purified samples appeared at 1077 cm −1 on the infrared spectrum, indicating the reaction between amino groups in APTES and epoxy groups in EVM-GMA happened successfully. Besides, the moisture curing curves of EVM-GMA-g-APTES compounds kept rising over time, which denoted that the chemical crosslink occurred and the Si–O–Si networks had been formed. Additionally, the modulus and tensile strength of moisture crosslinked samples were elevated remarkably with the increasing APTES content, and the samples with 2.5 phr APTES had relatively rational mechanical properties . Moisture crosslinking was feasible for EVM-GMA since the mechanical performance of the moisture crosslink was better than that of the peroxide crosslink system at a similar crosslink density .
Lin Zhengwei,Zhao Haotian,Chen Yanlu,Mao Jie,Hoch Martin,Shi Xinyan
An EPDM terpolymer grafted with silane vinyl triethoxysilane (EPDM-g-VTES) was prepared by melt grafting, with dicumyl peroxide (DCP) as an initiator. Next, dibutyl tin dilaurate was added as a catalyst to promote moisture crosslinking of EPDM-g-VTES. By means of the rheological response of the rubber compound, Fourier transform infrared spectroscopy, and moving die rheometer, the VTES graft ratio and DCP partial crosslinking (pre-crosslinking) of EDPM-g-VTES were characterized to show the feasibility of moisture crosslinking. The mechanical properties of moisture crosslinked EPDM-g-VTES specimens were tested by universal material tester. The results showed that when the weight ratio of VTES to DCP was fixed at 15:1, the VTES graft ratio and DCP partial crosslinking of EDPM-g-VTES increased with the increase of VTES content. But the torque in the moisture crosslinking curve of EPDM-g-VTES increased significantly with the extension of crosslinking time, which proved that EPDM grafted with VTES was cured by moisture successfully. The tensile strength and elongation at break of EPDM-g-VTES were improved by moisture cure. Furthermore, the moisture cured specimen with 3 wt% VTES had the best mechanical performance.
危险品化学品经营许可证（带存储）