乙烯系单体自由基聚合的阻聚效应(XX)取代哌啶羟胺及其稳定自由基对苯乙烯-甲基丙烯酸甲酯共聚合的影响

Inhibiting Effect on the Radical Polymerization of vinyl Monomers(XX)--Studies on the Effect of Hindered Hydroxylamine and Its Nitroxyl Radical in the Copolymerization of Styrene with Methyl Methacrylate

研究了２，２，６，６－四甲基－４－羟基哌啶羟胺（ＴＭＨＰＨＡ）和２，２，６，６－四甲基－羟基哌啶－１－氧自由基（ＴＭＨＰＯ）对偶氮二异丁腈（ＡＩＢＮ）６０℃引发的苯乙烯（Ｍ１）－甲基丙烯酸甲酯（Ｍ２）共聚合的行为．结果表明，两种阻聚剂对苯乙烯（Ｓｔ）－甲基丙烯酸甲酯（ＭＭＡ）共聚合均呈现良好的阻聚效应，其中ＴＭＨＰＨＡ略优于ＴＭＨＰＯ；同时观察到Ｓｔ－ＭＭＡ共聚表观活化能和竞聚率表现出的差异．当阻聚剂为２００μｇ时，共聚物组成发生改变，它们的恒比共聚点由对照实验的０．５２９分别变化为０．５４３（ＴＭＨＰＨＡ）和０．５６７（ＴＭＨＰＯ）．

The behaviors of 2,2,6,6 tetramethy 4 hydroxyl piperdine hydroxylamine (TMHPHA) and its stable nitroxyl radical(TMHPO), as inhibitors of the AIBN initiated copolymerication of styrene(M 1) methyl methacrylate (M 2), at 60℃, have been investigated by the dilatometric method. The results show that these two inhibitors have an effect on the inhibition of copolymerization St MMA, and the reactivity ratio of St to MMA obtained and active energy E obs  of copolymerization observed were different in these two inhibitors. When the amount of the inhibitor is about 200 μg, the composition of copolymer St MMA varies, and the azeotropic point of copolymer St MMA changes from 0.529 in the absence of inhibitor to 0.534 and 0.567 in the presence of TMHPHA and TMHPO respectively.