【作者】 戴世茂；

【导师】 詹晓力； 陈丰秋；

【作者基本信息】 浙江大学 ， 化学工程， 2006， 硕士

【摘要】 γ-氯丙基甲基二甲氧基硅烷（MCPS）含有氯丙基和甲氧基两类功能性基团，可用于制备多种偶联剂；也可与D₄共聚，得到侧基为氯丙基的新型有机硅高分子材料，进一步进行季铵化反应后可得到相应的有机硅季铵盐。本文分别对γ-氯丙基甲基二甲氧基硅烷/D₄、γ-氯丙基甲基二甲氧基硅烷/二甲基二甲氧基硅烷（DMMS）共聚体系在碱/酸性条件下的反应规律进行了研究。D₄/MCPS共聚体系在碱性条件下开环共聚时，发现产物的分子量很低，且有游离的氯离子生成，说明碱性催化剂与MCPS发生显著的脱氯反应，抑制甚至阻止了D₄/MCPS共聚。机理分析表明D₄/MCPS体系存在阳离子开环、脱氯和缩聚三个竞争反应，且以脱氯反应最易进行。不同的温度范围，脱氯反应遵循不同的机理；且建立了脱氯反应动力学模型，得到反应级数、速率常数和活化能。结果表明在40～80℃之间，反应为拟一级反应；温度升高，反应逐渐从拟一级向拟三级过渡，在120℃时为拟三级反应。D₄/MCPS共聚体系在酸性条件下开环共聚时，考察了催化剂用量、反应温度、单体配比和水分等因素对分子量和转化率的影响。发现在实验范围内，催化剂用量和反应温度的影响不明显；而单体配比和水分的影响较为显著。D₄/MCPS单体配比较低时，产物分子量很低，提高配比，分子量随之增加；水的存在会导致转化率显著降低。采用FTIR和NMR对D₄/MCPS体系在酸性条件下的聚合产物进行定性和定量分析，结果表明其可能为氯丙基封端的聚硅氧烷，机理分析亦支持了上述结论。二甲基二甲氧基硅烷/MCPS在酸性条件下共缩聚时，研究了催化剂用量、反应时间、反应温度、真空度等因素对反应的影响。该共聚体系可得到侧基为氯丙基的梳状结构的聚硅氧烷；可控制其分子量在4000～20000之间，用于季铵化反应，以获得具有抗菌作用的季铵盐型聚硅氧烷。更多还原

【Abstract】 γ -chloropropylmethyldimethoxysilane（MCPS） have chloropropy groups and double methoxy groups, so it can be used to produce some coupling agents or copolymerize with octamethylcyclotetrasiloxane（D4） to make the new siloxane copolymer which contains the chloropropy groups at side chains. The new copolymer and its devirant are comprehensively used in many fields, like Rubber Industry、 Plastic Industry、 Print or Industry of fine chemicals,etc.Taking potassium hydroxide as catalyst, we found the 3-chloropropylsilyl groups are attacked by potassium hydroxide or silanolate active propagation centers during the copolymerization of γ -chloropropylmethyldimethoxysilane with octamethylcyclotetrasiloxane. These attacking reactions produce a lot of free chlorine ions. The mechanism of the reactions is deduced and proved by the kinetic parameters which are obtained from experimental results. There are three competitive reactions in the copolymerization system, and the dechlorination reaction is the dominant one.Taking acid clay as catalyst, we suggest a new mechanism which about D4/MCPS copolymerization reaction. At the first step, the ring-opening reactions make D4 transform to silanol group. Then the silanol group reacts with SiOCH₃ group, which produce the SiOSi group. We find that the silanol group is very active, if the reaction system has many MCPS, the silanol group’s activity will be different with which often happens at a common acid catalyst polymerization system. It will not combine with catalyst to get the active center which can catalyse the polymerization reaction. It prefer to react with SiOCH₃ group to produce the SiOSi group、 H₂O or CH3OH; the active centers will be destroyed at this reaction, so we only can get some low molecular weight polymers. Meanwhile, the chloropropyl groups will end the polymer chains but not at the side chains.Taking acid clay as catalyst, we study the copolymerization between MCPS and other siloxanes. At last we get a appropriate reaction conditions to produce the polymer.更多还原