有机过氧化物与N,N-二羟烷基对甲苯胺引发体系的研究

<正> 有机过氧化二苯甲酰(BPO)与N,N-二甲基苯胺(DMA)组成的引发体系称为有机氧化还原引发体系.为了提高聚合速度和聚合物的颜色稳定性,发展了BPO-DMT(N,N-二甲基对甲苯胺)引发体系,并已应用于医用高分子的齿科材料和骨水泥中.文献[3]曾简单提到N,N-二2-羟乙基苯胺(DHEA)作为促进剂,其活性与DMA相似;另外BPO可分别与N,N-二(2-羟乙基)对甲苯胺(DHET)和N,N-二(2-羟丙基)对甲苯胺(DHPT)组成引发体系,作为烯类自由基聚合的室温固化剂,但对聚合速度和聚合动力学报道甚少.由于DHPT熔点较高又无刺激味道,因而很适用于自凝齿科林     

溶胶—凝胶法合成聚甲基丙烯酸甲酯／二氧化钛杂化聚合物材料

由共聚合在ＰＭＭＡ聚合物链段上引入了一－Ｓｉ（ＯＲ）３为功能团，通过溶胶－凝胶过程合成了ＰＭＭＡ／ＴｉＯ２杂化聚合物材料，溶剂抽提结构表明有化学键存在的杂化材料体系中凝胶的含量很高，通过ＦＴＩＲ测试材料结构进行了分析，由ＴＧＡ，ＤＳＣ测试分析了杂化材料体系中无机组份的含量材料性能的影响。     

STUDIES ON ORGANIC PEROXIDE/N, NDI (2-α-METHYL-ACRYLOYLOXY PROPYL)-PARA-TOLUIDINE BINARY SYSTEMS

The polymerization of methyl methacrylate (MMA) initiated by organic peroxide and polymerizable aromatic tertiary amine such as N, N-di (2-α-methylacryloyloxy propyl)-p-toluidine (MP)_2PT binary system has been studied. It was found that the (MP)_2PT promotes MMA polymerization, and the kinetics of MMA polymerization fits the radical polymerization rate equation. Based on the ESR studies and the end-group analysis the initiation mechanism is proposed.     

有机过氧化物与N-甲基-N-2-羟乙基苯胺引发体系的研究

 测定了有机过氧化物与N-甲基-N-2-羟乙基苯胺(HMA)体系引发MMA聚合的动力学方程和聚合表现活化能。由过氧化物/HMA/MNP的ESR波谱证实芳叔胺HMA中,与氮原子相连的亚甲基的氢被摘去形成相应的碳自由基,它能引发单体聚合成为聚合物的端基。这也由聚合物的UV光谱所证实,由实验结果提出这类体系的引发机理。     

聚丙烯酸甲酯及其模型化合物与O2的初始暗氧化反应

烯酸甲酯及其模型化合物２－甲丁酸甲酯与Ｏ２能够形成不稳定的接触电荷转移复合物。在无光照条件下，通Ｏ２放置一段时间以后再通Ｎ２，ＣＣＴ吸收峰不再完全消失，其残留峰的强度随存放时间的延长，温度的升高而增加，而形和峰位与原ＣＣＴ相似。     

吗啉类对甲基丙烯酸甲酯自由基聚合的影响

<正> 文献曾简要报道叔丁基过氧化氢(TBH)与脂环仲胺哌啶(P)体系能引发甲基丙烯酸甲酯(MMA)聚合,而TBH与脂环仲胺吗啉(MP)也可作为厌氧胶的引发体系.为了研究吗啉类化合物对有机过氧化物引发聚合的影响,本文采用四种有机过氧化物:过氧化苯甲酰(BPO)、过氧化月桂酰(LPO)、TBH、过氧化苯甲酸叔丁酯(TBPB),研     

聚丙烯腈的研究——丙烯腈在浓无机盐溶液中的氧化还原引发聚合

丙烯腈在浓硫氰化钠溶液中成功地应用氧化还原引发聚合。所用引发体系为TBH-TEA,TBH-DEA,TBH-MEA,TBH-DMA四类。当TBH与TEA二者克分子比为1∶1左右时,1小时内转化率可达90％以上,分子量为8.5万左右,不同体系的聚合速度与转化率的次序为TBH-TEA>TBH-DEA>TBH-MEA,而它们分别所得聚合物的分子量次序则恰恰相反。 当[TBH]/[TEA]的克分子比增加时则聚合速度增加,最高转化率也增加。以TBH-DMA为引发体系时,转化率最高在60％左右,当增加[DMA]/[TBH]的克分子比时,聚合速度增加但最高转化率反而下降,这与BPO与DMA体系的情况相同。 初步提出了TBH-醇胺引发体系的反应机理。     

β—二酮或β—三酮对铈（Ⅳ）盐引发烯类单体聚合的影响

研究了β－二酮或β－三酮（如：３－苄基乙酰丙酮，苯甲酰基丙酮，二苯甲酰基甲烷及３－苯甲酰基乙酰丙酮）对铈（Ⅳ）盐引发丙烯酰胺聚合的促进作用，测定了聚合反应速度及表观活化能，表明铈（Ⅳ）盐／β－二酮或β－三酮可组成活性很高的氧化还原体系，采用版自旋捕捉技术及ＥＳＲ谱研究了体系的初系级自由基结构，通过ＦＴＩＲ光谱端基分析检测这类体系引发丙烯腈所得聚合物端基有β－二酮结构，以此为基础，提出了这类体系引发     

PHOTOSENSITIVITY OF CERIC ION INITIATED ACRYLAMIDE POLYMERIZATION

Polymerization of acrylamide initiated by ceric ammonium nitrate alone has been studied in aqueous medium. The effects of UV light irradiation on the initial rates of polymerization, the activation energy and on the polymer molecular weights have been investigated. Compared with that in the dark, the rate of polymerization under UV light was accelerated to eleven times higher, and the overall activation energy was lowered markedly.     

STUDIES ON THE OXIDATION AND GRAFT COPOLYMERIZATION OF POLYETHERS

Polyethers could form hydroperoxide under air-oxidation or photo-oxidation in the presence of H_2O_2. The scission of ether linkage induced by moderate oxidation was prevented by controlling the reaction time and hydroperoxide concentration. The oxidation rate was affected by the end groups of polyethers. The decreasing order of oxidation rate for various poly(tetramethylene ether) glycol derivatives having different end groups are as follows: poly(tetramethylene ether) glycol (PTMG)>poly(tetramethylene ether)acetate (PTMGAC) >poly(tetramethylene ether) phenyl carbamate (PTMGPC). The urethane end groups in PTMGPC increase the resistance toward oxidation. Polyether hydroperoxide reacts with ferrous ion or N,N-dimethyl toluidine (DMT) to form polymericoxy radical which then initiates the graft copolymerization of vinyl monomers at low temperature, and was devoid of homopolymerization. The copolymer after separation and purification was proved to be a graft one by IR analysis and elemental analysis.