【作者】 王伟；

【导师】 卢咏来；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2018， 硕士

【摘要】 环氧化硅橡胶(ESR)是通过化学改性的方法将环氧基团连接到硅橡胶分子链上的一种新型硅橡胶。相比甲基乙烯基硅橡胶(MVQ),这种新型硅橡胶耐寒性提高,与此同时,其分子链极性增加,也改善了硅橡胶与金属粘合性能。本论文采用阴离子开环聚合的方法,发现采用延长合成催化剂反应时间,得到的硅橡胶的分子量分布变小。因此,我们采用此方法合成出了不同乙烯基含量的窄分布甲基乙烯基硅橡胶,这些硅橡胶数均分子量在20万到30万之间,多分散性分布小于2。用3-氯过氧苯甲酸(m-CPBA)直接将其环氧化改性,制备了环氧度约为5%-30%的环氧硅橡胶。采用了机械混炼法制备了环氧硅橡胶/气相法白炭黑(100/40)复合材料,并对其结构和性能进行了研究。研究表明,随着硅橡胶中环氧度的增加,气相法白炭黑在硅橡胶基体中的分散性改善,Payne效应减弱。与此同时,我们研究了过氧化物的用量对复合材料拉伸强度的影响,发现在添加0.08份硫化剂的情况下,环氧度为10%和20%的硅橡胶复合材料能够获得较高的拉伸强度。DMTA测试表明,损耗峰的峰值和峰宽随着环氧度的提高而增大。DSC测试表明,硅橡胶的环氧度从5%增加到30%,复合材料的玻璃化转变温度从-122.04℃升高到-107.51℃。TGA测试表明硅橡胶的环氧度不超过10%时,随着环氧度增加,耐热性有所提高。此外,环氧基团的引入有利于硅橡胶与铝制板材的粘结,环氧度为20%硅橡胶的剪切强度最大,达到了 35.2N cm-2。最后,本论文还探索用甲酸和过氧化氢原位生成过氧甲酸对硅橡胶进行环氧化改性。尝试了不同溶剂(甲苯,环己烷,正庚烷,环己酮/二甲苯,环己烷/正庚烷),不同相转移催化剂(PEG,Tween-80,OP-10),不同反应温度(30℃,40℃,50℃)和反应配比等条件,但未能实现环氧化。更多还原

【Abstract】 Epoxidized silicone rubber(ESR)is a novel kind of silicone rubber,which is synthesized by introducing epoxy group into molecular chain of silicone rubber through chemical modification.Compared to methyl vinyl silicone rubber(MVQ),the cold resistance of this new type of silicone rubber was improved.At the same time,the polarity of its molecular chain was increased,which also improved the adhesive property of silicone rubber and metal.In this paper,it was found that the molecular weight distribution of the obtained silicone rubber becomes smaller by prolonging the reaction time of the synthetic catalyst and using anionic ring-opening polymerization(AROP)method.As a result,the methyl vinyl silicone rubber with different vinyl content was synthesized by using these methods above.The molecular weight of silicon rubber is between 200,000-300,000,and the polydispersity is less than 2.In addition,by using 3-chloroperoxybenzoic acid(m-CPBA)as oxidant which could directly epoxidize methyl vinyl silicone rubber,the silicone rubber with epoxy degree from 5%to 30%was prepared.Furthermore,the epoxidized silicone rubber/fumed silica(100/40)composites were prepared by mechanical mixing and the structure and properties of these composites were studied.The results showed that the dispersibility of fumed silica in epoxidized silicone rubber matrix was improved and the Payne effect was weakened with the increase of epoxy degree.Meanwhile,the effect of the peroxide amount on the tensile strength of the composites was studied.It was found that in the case of adding 0.08 phr of a vulcanizing agent and a silicone rubber having an epoxy degree of 10%to 20%,the composite material can obtain a higher tensile strength.The DMTA test showed that both the peak value and peak width of the loss peaks increased with the increase of epoxy degree.The DSC test indicated that when the epoxy degree was in the range of 5%to 30%,the glass transition temperature(Tg)of the composites changed from-122.04℃ to-107.51℃.The TGA test showed that the heat resistance of the composites improved slightly with the increase of epoxy degree when the epoxy degree was less than 10%.Moreover,the introduction of epoxy group facilitated the adhesion of silicone rubber and aluminum sheets.Silicone rubber with 20%epoxy degree has the highest shear strength,which reaches 35.2 N cm-2.Finally,we tried to carry out epoxidation of silicone rubber by peroxyformic acid in situ generated by formic acid and hydrogen peroxide.Different solvents(toluene,cyclohexane,n-heptane,cyclohexanone/dimethylbenzene,cyclohexane/n-heptane),different phase transfer agents(PEG,Tween-80,OP-10),different reaction temperature(30℃,40℃,50℃)and reaction ratios were tried,but the epoxidation was not achieved.更多还原