Zhan Xibing, Cai Xiqing, Zhang Junying
College of Chemical and Material Engineering, Quzhou University Zhejiang 324000 China.
Lab of Adhesives and In-situ Polymerization Technology, Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology Beijing 100029 China
RSC Adv. 2018 Apr 3;8(23):12517-12525. doi: 10.1039/c7ra13375h.
A novel cross-linker polymethyl(ketoxime)siloxane (PMKS) with dense pendant reactive groups based on polymethylhydrosiloxane (PMHS) was synthesized dehydrocoupling reaction. The novel PMKS cross-linker was applied to a hydroxyl-terminated polydimethylsiloxane (HPDMS) matrix to prepare a series of novel RTV silicone rubbers. The chemical structure of PMKS and curing reaction between HPDMS and PMKS by hydrolytic condensation were verified by IR spectroscopy and H NMR. Thermal stability and mechanical properties of these novel RTV silicone rubbers have been studied by means of thermal gravimetric analysis (TGA) and universal tensile testing machine, respectively. The results displayed that a pronounced enhancement effect of the novel cross-linker PMKS on thermal stabilities and mechanical properties of RTV silicone rubbers as compared with the traditional cross-linking agent of methyltris(methylethylketoximino)silane (MTKS). Subsequently, the degradation residues were also characterized by FT-IR and X-ray photoelectron spectrometer (XPS). It was found that the striking enhancements in thermal properties and improvements on mechanical properties could be the synergistic effect of the T-type branched structure of PMKS cross-linker, formation of dense PMKS phase in the chain network by self-crosslinking and the uniform distribution of PMKS cross-linker in the HPDMS matrix.
通过脱氢偶联反应合成了一种基于聚甲基氢硅氧烷（PMHS）的具有密集侧基反应性基团的新型交联剂聚甲基（酮肟）硅氧烷（PMKS）。将这种新型PMKS交联剂应用于端羟基聚二甲基硅氧烷（HPDMS）基体中，制备了一系列新型室温硫化硅橡胶。通过红外光谱（IR）和核磁共振氢谱（H NMR）对PMKS的化学结构以及HPDMS与PMKS之间的水解缩合固化反应进行了验证。分别借助热重分析（TGA）和万能拉伸试验机对这些新型室温硫化硅橡胶的热稳定性和力学性能进行了研究。结果表明，与传统交联剂甲基三（甲基乙基酮肟基）硅烷（MTKS）相比，新型交联剂PMKS对室温硫化硅橡胶的热稳定性和力学性能具有显著的增强作用。随后，还通过傅里叶变换红外光谱（FT-IR）和X射线光电子能谱仪（XPS）对降解残渣进行了表征。发现热性能的显著提高和力学性能的改善可能是PMKS交联剂的T型支化结构、通过自交联在链网络中形成致密的PMKS相以及PMKS交联剂在HPDMS基体中均匀分布的协同效应。
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