【作者】 张鹏；

【导师】 冯莺；

【作者基本信息】 青岛科技大学 ， 高分子化学与物理， 2009， 硕士

【摘要】 本文首次研究了丙烯酸(AA)单体和4-乙烯基苄氯(4-VBC)单体的自由基共聚合反应。采用IR技术、1H-NMR技术和GPC方法表征了产物共聚物P(AA-co-VBC)的组成和分子量。采用Fineman-Ross法和Kelen-Tudos法计算了单体的竞聚率:根据Fineman-Ross法,丙烯酸单体(M1)和4-乙烯基苄氯单体(M2)的竞聚率分别为r1= 0.50±0.06, r2=1.52±0.15;根据Kelen-Tudos法,两单体的竞聚率分别为r1= 0.43±0.21, r2 = 1.31±0.14。研究结果表明:在此共聚体系中,由于r1 < 1,r2 > 1,r1 r2 <1,从而共聚物组成曲线始终处于恒比共聚组成曲线下方,属于非理想共聚合体系。由所得竞聚率计算了AA-VBC共聚物主链中两单体单元的序列结构,结果表明可以通过调节两单体投料比来控制两单体单元在大分子链中的序列长度分布:当f2= 4.77%时,共聚物中4-VBC单元序列长度为1的含量占93.8%,表明4-VBC单元基本上被AA单元体完全分隔开;当f2=35.53%时,两种单体单元序列长度为1(交替共聚结构)的含量均超过55%,其余的为梯度共聚物结构;当f2=78.62%时,AA单元序列长度为1的含量占86.0%,AA主要以单个单元分布在4-VBC链中。另外,P(AA-co-VBC)的数均分子量随着单体4-VBC投料量的增加而增大。本文第二部分以产物共聚物P(AA-co-VBC)作为大分子引发剂,在FeCl2/PPh3催化下,引发了甲基丙烯酸甲酯(MMA)的ATRP反应,制备了结构明确的主链亲水、支链亲油的两亲性梳型共聚物P(AA-co-VBC)-g-PMMA。采用IR技术、1H-NMR技术和GPC方法表征了共聚物的结构参数和分子量,计算了共聚物的平均接枝数、平均支链长度、接枝率和接枝效率。第三部分考察了P(AA-co-VBC)-g-PMMA在水溶液中的溶胀行为和溶胀动力学:结果表明降低pH值、降低温度,加入电解质都会降低接枝共聚物的吸水倍率;接枝率增加,接枝共聚物的吸水倍率亦随之降低;随着pH值的降低,溶胀扩散机理由Fickian扩散逐渐转变为非Fickian扩散,在多数环境中的溶胀主要受溶剂分子的扩散为主,表现为Fickian扩散机理。更多还原

【Abstract】 The radical copolymerization of acrylic acid (M1) and 4-Vinylbenzylchloride (M2) in dioxane was firstly studied. A series of copolymers with different compositions were obtained from feed ratios of M1:M2 = 95.2:4.8 to 21.4:78.6. The composition and average molecular weights of acrylic acid (AA) and 4-Vinylbenzylchloride (4-VBC) copolymers were determined by IR,1H-NMR and GPC. According to the composition of P(AA-co-VBC), the reactivity ratios of AA-VBC copolymerization system calculated by the Fineman-Ross method were r1= 0.50±0.06 and r2= 1.52±0.15, almost the same as r1 = 0.43±0.21 and r2 = 1.31±0.14 by the extended Kelen-Tudos method. The results showed that r1 < 1 and r2 > 1, and r1 r2 < 1, and the performance of AA-VBC copolymerization system is non-ideal copolymerization. AA in copolymer is always smaller than AA in feed. The composition curve is always below the diagonal. On the basis of the reactivity ratios of two monomers, the sequence-length distribution in the AA-VBC copolymers was obtained. Sequence-length distribution of AA and 4-VBC in the AA-VBC copolymers can be controlled through change of feed ratios. For f2 = 4.77%, the probability of the 4-VBC sequence of 1 unit in the copolymer chain is 93.8 % ,the monomer unit of 4-VBC is mostly separated by the sequence of AA; and for f2=35.53%, the probability of the 4-VBC and AA sequence of 1 unit in the copolymer chain is above 55%(alternating tendency prevails), the rest of copolymer is gradient structure; and in the case of f2 = 78.62%, the probability of the AA sequence of 1 unit in the copolymer chain is 86.0%, the monomer unit of AA is individually separated in the chain of 4-VBC. In the presence of constant initiator concentration, the gradual increase in the feed of 4-VBC was accompanied by a increase in number-average molecular weight of P (AA-co-VBC).Then methyl methacrylate (MMA) was grafted onto P (AA-co-VBC) backbone using PhCH2Cl group in VBC unit of P (AA-co-VBC) as an initiation site and FeCl2/triphenyl phosphine complex as a catalyst. The resulted copolymer (AA-co-VBC)-g-PMMA with a comb-like branched structure has a hydrophilic backbone (PAA) and hydrophobic side chains (PMMA). The structure parameters and average molecular weights of P(AA-co-CMS)-g-PMMA were determined by IR,1H-NMR and GPC. The average graft number, the average length of side chains, the graft ratio and the graft efficiency were investigated. The swelling behavior and dynamics of the comb-like branched polymer in aqueous solution was also investigated. The gradual decrease of swelling ratios was accompanied by the decrease of pH and temperature, and the increase of concentration of NaCl solution and graft ratio. The kinetic exponents indicated that the swelling transport mechanisms transformed from Fickian diffusion to non-Fickian transport as the decreasing pH. In most of surroundings, swelling transport mechanisms were controlled by solvent diffusion and fitted by Fickian model.更多还原