Control of Branching in Radical Polymerization Based on New Concept

基于新理念的自由基聚合支化控制

• 批准号: 10650869
• 负责人: YAMADA Bunichiro
• 金额: $ 1.92万
• 依托单位: Osaka City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650869/
• 关键词: Radical Polymerization; Catalytic chain transfer; Branched polymer; Cobaloxime; Addition-fragmentation chain transfer; Cross-linking; Polymerizable chain transfer agent; Bifunctional chain transfer agent; 2分子停止; ブロックポリマー

A non-polymcrizable dimer of methyl methacrylatc (MMA) is feasible to radical addition to yield an adduct radical which is too stable to react mutually nor to add to monomer. The adduct radical primarily undergoes coupling with propagating radical to link two polymer chains through the dimer unit. The addition and coupling involving the dimer could be employed for gel-free branch formation in radical polymerization. The reactivities of various dimers of α-methyl vinyl compounds such as MMA, metherylonitrile (MAN), α-methylstyrene, and p-substituted α-methylstyrene were examined. Among these, the dimer of MAN participated only in addition/coupling to connect two polymer chains. Polystyrene radical added to the MMA dimer and mainly couple with the adduct radical. However, the adduct radical also yield the polystyrene bearing the unsaturated end group through β-fragmentation of the adduct radical. The dimer structure was introduced into polymer using a polymerizable addition-fragmentation chain transfer agent and a bifunctional addition-fragmentation chain transfer agent. These transfer agents involved one and two α-alkylthiomethylacryloyl groups as chain transferable groups. The polymerization of MMA in the presence of polymerizable transfer gent gave the poly(MMA) with the chain transferable side group which was further involved in addition/fragmentation chain transfer to link poly(MMA) chain. The side chain could also involve branching points. The polymerization of styrene in the presence of the poly(MMA) was found to result in a hyper branched block copolymer. The bifunctional chain transfer agent introduced the carbon carbon double bond to both end of poly(MMA). These double bonds were employed for addition/coupling of polystyrene radical to afford a branched block copolymer without gelation.

不可聚合的甲基丙烯酸甲酯（MMA）二聚体可以通过自由基加成生成加合自由基，该加合自由基太稳定，不能相互反应，也不能加到单体上。加合自由基主要通过二聚体单元与扩展自由基偶联以连接两条聚合物链。涉及二聚体的加成和偶联可用于自由基聚合中无凝胶分支的形成。考察了各种α-甲基乙烯基化合物二聚体MMA、甲腈（MAN）、α-甲基苯乙烯和对取代α-甲基苯乙烯的反应活性。其中，MAN二聚体仅参与加成/偶联连接两条聚合物链。聚苯乙烯自由基加入到MMA二聚体中，主要与加合自由基偶联。然而，加合自由基也会通过加合自由基的β-断裂生成带有不饱和端基的聚苯乙烯。采用可聚合加成-破碎链转移剂和双官能团加成-破碎链转移剂将二聚体结构引入聚合物中。这些转移剂含有一个和两个α-烷基硫甲基丙烯基作为链转移基团。在可聚合转移剂的作用下，聚甲基丙烯酸甲酯的聚合得到了具有链可转移侧基的聚甲基丙烯酸甲酯，该侧基进一步参与加成/裂解链转移以连接聚甲基丙烯酸甲酯链。侧链也可能包含分支点。发现苯乙烯在聚甲基丙烯酸甲酯（MMA）存在下的聚合会产生超支链嵌段共聚物。双功能链转移剂将碳碳双键引入聚丙烯酸甲酯的两端。这些双键被用于聚苯乙烯自由基的加成/偶联，以获得不凝胶化的支链嵌段共聚物。

项目成果

山田 文一郎、鴻巣 修、田中 健太、奥 文法: "Preparation of branched polymer by radical polymerization using polymerizable chain transfer agent"Polymer. (印刷中).

Bunichiro Yamada、Osamu Konosu、Kenta Tanaka、Grammar Oku：“使用可聚合链转移剂通过自由基聚合制备支化聚合物”（正在出版）。