“Cr^(2+)+BPO”体系引发的活性自由基聚合

Living Radical Polymerization Initiated by the Aged “Cr^2+ +BPO” in DMF

本文以陈化的“Ｃｒ２＋＋ＢＰＯ”为引发剂，以Ｎ，Ｎ二甲基甲酰胺（ＤＭＦ）为溶剂，在各种条件下引发了甲基丙烯酸甲酯（ＭＭＡ）的聚合。通过对低单体浓度下的聚合反应的研究，证明了ＰＭＭＡ的相对分子质量随单体转化率而上升的现象不是由凝胶效应所造成的。通过对陈化体系变温聚合的研究，及对其聚合产物的立构规整性的分析，进一步说明了是由三价铬离子络合的链自由基引发ＭＭＡ进行“活性”聚合的这一反应机理。表１，图４。

Abstract The polymerization of methyl methacrylate (MMA) initiated by the aged chromium(Ⅱ) acetate (Cr^2+ ) and benzoyl peroxide (BPO) in dimethylformamide (DMF) are studied. By means of studying the polymerization of MMA at its low concentration, we prove that the molecular weight of the PMMA incrasing with monomer conversion is not affected by the gel effect. By means of studying the steroregularity of the PMMA at different polymerization temperature, we comfirm that a living polymerzation occurs and the active spcies is the radical complex of transition metal ion Cr^3+ .1 table,4 drawings,6 references