【作者】 彭志霞；

【导师】 程斌；

【作者基本信息】 北京化工大学 ， 高分子化学与物理， 2004， 硕士

【摘要】 本课题以丙烯酸丁酯(BA)和对叔丁基酚保护的间异丙稀基枯基异氰酸酯(BTMI)进行共聚,合成带“隐性”异氰酸酯官能团的聚合物,在一定温度下解离出活性异氰酸酯官能团,同时与异胞嘧啶反应“原位生成”嘧啶酮,通过嘧啶酮间的四氢键自组装成超分子聚合物网络,制成以此网络为基础的热塑性弹性体。研究工作主要包括如下几个方面:用间异丙稀基枯基异氰酸酯(TMI)与对特丁基苯酚反应合成出保护的α-甲基苯乙烯型单体(BTMI),并且研究了其与丙烯酸丁酯(BA)的共聚合,考察了单体配比、反应时间等因素对共聚反应的影响。求出了60℃下共聚合的竞聚率rBTMI=0.13, rBA=0.22以及共聚物中的构型参数σ=0.33,并且计算共聚物的组成分布和序列分布长度。实验表明,BTMI的反应活性较BA低。通过BA与BTMI的乳液聚合得到含隐性异氰酸酯官能团的聚合物高分子链,研究了聚合过程中反应时间、共聚单体配比、乳化剂用量对转化率及聚合物分子量大小的影响,还研究了乳胶粒子的大小及其分布情况。本论文用傅立叶红外光谱在程序升温和等温条件下研究了对特丁基苯酚保护间异丙稀基枯基异氰酸酯(BTMI)与丙烯酸丁酯共聚物的热分解动力学特征,计算了热分解动力学参数。探讨了对特丁基苯酚保护间异丙稀基枯基异氰酸酯(BTMI)样品的热分解过程。得出其热分解的活化能为Ea = 98.433kJ/mol;反应级数为一级。热分解指前因子为γ=2.987×107秒-1 。通过检测到异氰酸酯(-N=C=O, 2270cm-1)的吸收峰证实,160℃开始对特丁基苯酚保护基团开始<WP=4>热解,随着温度的升高,热解速度加快。但是到280℃以上时,热解出的异氰酸酯(-N=C=O )发生自聚。对特丁基苯酚保护间异丙稀基枯基异氰酸酯(BTMI) 与丙烯酸丁酯(BA)的共聚物和与甲基异胞嘧啶在170℃恒温体系中,以二甲亚砜为溶剂进行自组装。红外图谱数据等数据证明,说明解保护后的聚合物与甲基异胞嘧啶发生了反应,而且发生氢键自组装。但是,体系中还有其他一些副反应。更多还原

【Abstract】 In this thesis, a new synthetic route to prepare polymer networks is described . BA is copolymerized with p-t-butyl-phenol blocked dimethyl-m-isopropenyl-benzyl isocyanate, which can be deblocked via pyrolysis. On heating, the copolymer can be converted to a polymer with pending isocyanate groups, which react with 6-methyl methylisocytosine. A polyacrylate network is expected to form via hytrogen-bonded self-assembly ureido-pyrimidone dimmer. The following researches were carried out.Firstly, p-t-butyl-phenol blocked dimethyl-m-isopropenyl-benzyl isocyanate (BTMI) was synthesized and copolymerized with n-butyl acrylate (BA). The monomer reactivity ratios, rBTMI=0.13, rBA=0.22, were obtained at 60℃by Kelen-Tudos method, and the co-isotactic parameter of BTMI with BA, σ=0.33, was obtained. The results show the reactivity of BTMI is less than one of BA.Secondly, blocked isocyanate polymer was synthesized by the emulsion polymerization of BTMI and BA.The effect of reaction time ,monomer ratio, emulifier SDS quantity on conversion and molecular weight were investigated. Thirdly, the kinetics of pyrolysis of the copolymer of p-t-butyl-phenol blocked dimethyl-m-isopropenyl-benzyl isocyanate and butyl acrylate was studied by in-situ quantitive FTIR and temperature programmed in the ground of pure N2 . The -N=C=O absorption at 2270cm-1 was monitored with the an absorption peak for the N-H group reducing. A number of spectra were recorded over a wide temperature range. It shows <WP=6>the beginning temperature of the decomposition is 160℃ and isocyanates deblocked are self-oligmerized above 280℃. The activiation energy is 98.433kJ/mol and the reaction order is 1 for the first stage ; the exponential factor (γ) is 2.987×107s-1 . Finally, the self-assembly sepermolecular network was formatted by in-situ self-combination with methylisocytosine, after the copolymer of p-t-butyl-phenol blocked dimethyl-m-isopropenyl-benzyl isocyanate and butyl acrylate was degraded in solvent dimethyl sulfoxide at 170℃.更多还原