Thermal and Photo-Induced Reactions of Polymer Radicals in γ-Irradiated Poly(alkyl methacrylate)
Thermal and Photo-Induced Reactions of Polymer Radicals in γ-Irradiated Poly(alkyl methacrylate)
复制标题
γ-辐照聚（甲基丙烯酸烷基酯）中聚合物自由基的热和光诱导反应
DOI：
10.1295/polymj.22.835
复制
发表时间：
1990
期刊：
影响因子：
2.8
通讯作者：
T. Ichikawa
中科院分区：
文献类型：
--
作者：
Migaku Tanaka;H. Yoshida;T. Ichikawa
用电子自旋共振波谱研究了聚甲基丙烯酸甲酯和聚甲基丙烯酸乙酯在γ辐照下产生的自由基物种的热反应和光诱导反应。低温下的γ辐照产生了三种主要的自由基物种，即侧链-COOCnHnN+1·−阴离子自由基和-CoO-Ċ-−-1H2-−-1自由基以及主链-ĊH-自由基。通过质子转移到聚合物分子，阳离子自由基立即转化为中性自由基。用可见光照射聚合物阴离子自由基会导致电子脱离或酯基烷基的消除而形成烷基。紫外光照射可使-CoO-Ċ-hcn-−-1H2n-−-1自由基转化为酰基类型-Ċ=O自由基。-CoOĊhcn−1H2 n−1和-Ċ=O自由基都是断裂型·C(CH3)(COOC nH2 n+1)CH2-自由基的前体。
Thermal and photo-induced reactions of radical species generated by γ-irradiation of poly(methyl methacrylate) and poly(ethyl methacrylate) have been investigated by means of ESR spectroscopy. The γ-irradiation at cryogenic temperature leads to the formation of three major radical species, side chain –COOCnH2n+1·− anion radicals and –COOĊHCn−1H2n−1 radicals, and main chain –ĊH– radicals. Cation radicals are immediately converted to the neutral radicals by proton transfer to the polymer molecules. Illumination of the polymer anion radicals with visible light leads to electron detachment or the elimination of ester alkyl groups to form alkyl radicals. Illumination with UV light leads to the conversion of the –COOĊHCn−1H2n−1 radicals to acyl-type –Ċ=O radicals. Both the –COOĊHCn−1H2n−1 and the –Ċ=O radicals are the precursor of scission-type ·C(CH3)(COOCnH2n+1)CH2- radicals.