摘要
在非平衡催化剂作用下,通过α,ω-端羟基聚甲基三氟丙基硅氧烷和亚苯基二硅醇单体的脱水缩聚反应,制得一系列α,ω-端羟基亚苯基氟硅聚合物,并研究了反应时间、催化剂用量、反应物浓度、单体比例等因素对所得聚合物的状态、特性黏度、分子量及分布、共聚组成的影响。采用红外、核磁、流变仪、热分析等手段对聚合物的结构、室温交联反应性、力学性能、耐高温性能和玻璃化转变进行了研究。结果表明,向主链中引入亚苯基在显著提高聚合物耐高温性能的同时,还有助于交联反应速率和力学性能的改善,并且当亚苯基含量低于30%(mol)时不会对聚合物的玻璃化温度(Tg)产生不利影响。分析原因,亚苯基的插入抑制了有机硅链的成环降解且提高了链的刚性(有利于耐高温性),客观上隔开并降低了大体积三氟丙基侧基对端羟基的屏蔽效应(有利于交联反应性),因而将聚合物制备成氟硅密封胶,具有较好的交联性能、力学性能和耐高低温性能。
A series of phenylene-containingα,ω-hydroxy-terminated fluorosilicone polymers were synthesized by dehydration polycondensation in the presence of non-equilibrium catalyst fromα,ω-hydroxy-terminated poly(methyltrifluoropropyl)siloxanes and phenylene-containing disilanol monomers.The effects of reaction time,catalyst dosage,reactant concentration,and monomer ratio on the appearance,intrinsic viscosity,molecular weight and distribution,and copolymer composition of the obtained polymers were studied.Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance spectroscopy(NMR),rheometer and thermal analysis were utilized to study their chemical structure,room temperature crosslinking reactivity,mechanical property,thermal resistance,and glass transition.The results show that the introduction of phenylene into the main chain not only significantly improves the high temperature resistance of the polymer,but also contributes to the improvement of the crosslinking reaction rate and mechanical properties,and when the phenylene content is lower than 30%(mol),it does not adversely affect the glass transition temperature(Tg)of the polymer.It is reasonable that the insertion of phenylene inhibits the cyclization degradation and simultaneously improves the stiffness of the siloxane chain,which is beneficial to thermal resistance.Besides,the terminal silanol is separated from bulky trifluoropropyl side groups by the insertion of phenylene,and thus their shielding effect is reduced,which is helpful to the crosslinking reactivity.Therefore,the polymers can be utilized to prepare fluorosilicone sealants which show good crosslinking property,physical property,and high and low temperature resistance.
作者
刘润竹
储甜甜
张孝阿
王成忠
张军营
LIU Runzhu;CHU Tiantian;ZHANG Xiaoa;WANG Chengzhong;ZHANG Junying(Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education,College of Materials Science and Engineering,Beijing University of Chemical Technology,Beijing 100029,China)
出处
《化工学报》
EI
CSCD
北大核心
2023年第3期1360-1369,共10页
CIESC Journal
基金
航天化学动力技术重点实验室开放基金项目(STACPL 120201B07)
山东省重大科技创新工程(2019JZZY020232)。
关键词
亚苯基
氟硅
聚合物
合成
催化
非平衡催化剂
热稳定性
phenylene
fluorosilicone
polymer
synthesis
catalysis
non-equilibrium catalyst
thermal stability
