【作者】 贾中锋；

【导师】 冯圣玉；

【作者基本信息】 山东大学 ， 高分子化学与物理， 2008， 硕士

【摘要】 含碳官能基的聚硅氧烷除具有聚硅氧烷许多优良性能外,还可利用其官能基的反应活性,与其他聚合物反应,以形成具有特殊性能的聚合物,在保留了有机聚硅氧烷优异性能的同时又赋予其新的性能。该类聚合物在许多领域得到广泛应用。然而,许多碳官能基的引入使得聚硅氧烷的热稳定性降低,影响了在某些方面的使用。搞清该类聚合物的热降解规律及其影响因素,对于控制热降解反应、更好地利用该类化合物以及改进和研制具有更优异性能的聚合物具有十分重要的意义。本论文通过硅氢加成法合成含碳官能基的硅烷单体,然后利用阴离子开环聚合法,以含有乙酰氧乙基的官能基环硅氧烷、八甲基环四硅氧烷（D₄）、六甲基二硅氧烷（MM）为起始反应物,合成了含有乙酰氧乙基的官能性聚硅氧烷。对影响反应的催化剂、温度、物料摩尔比等各因素进行了研究,得出了较为合理的实验条件:本体硅氢加成反应中,以双封头-Pt为催化剂,不饱和化合物和Si-H键的比例为1.2:1,反应温度控制在60-65℃,反应时间12h,整个体系处于无水无氧状态进行反应;阴离子聚合反应中,以Me₄NOH硅醇盐为催化剂,在80-85℃下,采用分步加料法进行聚合反应,得到了乙酰氧乙基聚硅氧烷。用红外光谱、核磁共振、GPC、激光光散射等手段分析了产物的结构;并用TG等手段对所得聚合物的热性能进行详细研究,考察了官能团含量以及分子量对其耐热性的影响;采用改进的Freeman-Carroll方法对不同温度范围内的热解活化能、反应级数、速率常数进行了估算,并得到其表观的降解动力学机理;利用量子化学方法计算分析H₃SiCH₂CH₂OOCCH₃的热降解机理,发现其热降解反应有两种非竞争性反应路径。在聚硅氧烷主链上引入官能团已经引起人们很大的重视,对聚硅氧烷进行化学改性和修饰是一个永远的挑战;进行这方面的研究,对于寻找新的交联方法,研制特殊性能的有机硅高聚物是有理论价值和应用前景的。现在人们已经对聚硅基酯在环境和生物医药领域的应用非常感兴趣,在棉纺织工业聚硅基酯作为液体交联剂影响抗水性,具有硅基酯末端基团的聚硅氧烷可用来作为离子聚合的保护试剂以及粘度降低试剂。因此,乙酰氧乙基聚硅氧烷的热降解研究对深入研究其性能、扩大其使用范围具有重要的理论和实际意义。更多还原

【Abstract】 In spite of possessing a variety of unique and superior properties, carbofunctionalized polysiloxanes play important roles in modifitions of organic polymers,such as the copolymerization of polysiloxanes and organic polymers,with the aid of the reaction activity of the carbofunctional groups,to endow the organic polymers with the excellent properties of the polysiloxanes.This kinds of polymer is rapid developmet in silicone chemistry,and an active research field.However,because of the decomposition or rearrangement under certain conditions,their applications are limited to some extent.Understanding their rearrangement conditions and mechanisms will be of great important values for the control and application of these compounds.In this thesis,carbofunctionalized silicane monomer was synthesized with hydrosilation reaction.Acetoxyethylcyclicsiloxane、octamethylcycotetrasiloxane（D₄）、hexamethyldisiloxane（MM）were used as comonomers to anionic ring-opening copolymetize under base catalysts in this experiment.Studies on molar ratio of monomers,catalysts and polymerization temperature were our main focuses.We obtained a more reasonable experimental conditions:no solvent,the mol ratio of unsaturated compound and the Si-H is 1.2:1,the optimal reaction temperature was 60-65℃for 12h,anhydrous and anaerobic system state in the hydrosilation reaction.The optimal polymerized experiment condition is as the following:Me₄NOH siloxanolate is the catalyst,the optimal reaction temperature 80-85℃,fractinal step method.We synthesized a series of carbofunctionalized polysiloxanes,and their molecular structure were characterized by FT-IR、¹HNMR etc.We also use the TGA to investigate thermal properties of the polymer.Effect of molecular weight,and cotent of functional group on the polymer was also explored.We also analysized thermal degradation activation energy,reaction order,reaction rate constant under the different temperature range by the corrected Freeman-Carrol methods.Quantum chemistry method was used to calculate the thermal degradation mechanisms of H₃SiCH₂CH₂OOCCH₃ and got the real degradation mechanism.There are two kinds of reactions in this system,and both of them are noncompetitive.The carbofunctional group introducted in the polysiloxane chain has aroused great attention.Chemical modified is always a challenge.There are much theoretical value and application prospects in searching for new cross-linking method and developing special performance polysiloxane. Now,people are interested in application of the silica ester,especially in the application of the environment and biomedicine.Polysilica-ester can be used as the water resistance in the textile industry,the protection reagents of the ionic polymerization,application of the photography and viscosity-reduced reagents.Therefore,studied on the thermal degradation mechaniam of acetoxyethylpolysiloxane,can contribute to the deeper study of its performance,and expand the scope of its application.更多还原