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首页> 外文期刊>Macromolecules >Radical Polymerization of Pendant (Meth)acrylates on a Rigid Helical Polyisocyanate Backbone Producing Poly(meth)acrylates with 'Ideally' Atactic Main Chain Configuration
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Radical Polymerization of Pendant (Meth)acrylates on a Rigid Helical Polyisocyanate Backbone Producing Poly(meth)acrylates with 'Ideally' Atactic Main Chain Configuration

机译：在刚性螺旋多异氰酸酯骨架上生成（理想）无规主链构型的聚（甲基）丙烯酸酯的侧基（甲基）丙烯酸酯的自由基聚合

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This study includes a topic that poly(methyl methacrylate) (PMMA) with an ideally atactic main chain configuration, approximately triad tacticities of mm/mr/rr = 1/2/1, has been produced in solution by the one-dimensionally regulated radical polymerization using rigid helical polyisocyanate as a macromolecular template. Three types of isocyanate monomers with pendant (meth)acryloxy groups, such as 2-(methacryloxy)ethyl isocyanate (MOI), 2-[2-(methacryloxy)ethoxy]ethyl isocyanate (MOI-EO), and 2-(acryloxy)ethyl isocyanate (AOI), were polymerized using a titanium alkoxide complex to produce the corresponding polyisocyanates, MOI-n, MOI-EO-n, and AOI-n, respectively, in which n represents the number-averaged degree of polymerization. From the SAXS measurements of MOI-26 in hexafluoro-2-propanol and MOI-EO-38 in tetrahydrofuran at 25 degrees C, the polyisocyanates were found to be considered as rigid rod molecules. The radical polymerization of the pendant (meth)acryloxy groups was performed, and the polyisocyanate template was removed by alkali hydrolysis followed by methyl esterification, eventually producing the poly[methyl (meth)acrylate]s. The diad, triad, and pentad tacicities of the products were determined by the H-1 and C-13 NMR spectra, and these probabilities followed those calculated based on the Bernoulli statistics. The influences of the polymerization conditions, such as polymerization temperature and monomer concentration, on the tacticity of the final polymers were clarified. The effect of the flexible spacer between the polymerizable group and polyisocynate template was also evaluated. The radical polymerizations in which the polymerizable groups are molecularly regulated on a rod-like helical polyisocyanate backbone produced vinyl polymers with inimitable tacticities even in the solution state.
机译：这项研究包括一个主题，即一维调节自由基在溶液中产生了具有理想无规主链构型的聚（甲基丙烯酸甲酯）（PMMA），大约三元组立构规矩为mm / mr / rr = 1/2/1。使用刚性螺旋多异氰酸酯作为大分子模板进行聚合。具有（甲基）丙烯酰氧基侧基的三种异氰酸酯单体，例如异氰酸2-（甲基丙烯酰氧基）乙基酯（MOI），异氰酸2- [2-（甲基丙烯酰氧基）乙氧基]乙基（MOI-EO）和2-（丙烯酰氧基）使用钛醇盐配合物聚合异氰酸乙酯（AOI），分别生成相应的多异氰酸酯MOI-n，MOI-EO-n和AOI-n，其中n表示数均聚合度。从六氟-2-丙醇中的MOI-26和四氢呋喃中的MOI-EO-38在25摄氏度的SAXS测量中，发现多异氰酸酯被视为刚性杆分子。进行（甲基）丙烯氧基侧基的自由基聚合，并通过碱水解除去甲基异氰酸酯模板，然后进行甲基酯化，最终产生聚[（甲基）丙烯酸甲酯]。通过H-1和C-13 NMR光谱确定产物的二元组，三元组和五元组的直度，这些概率遵循基于伯努利统计数据计算的概率。阐明了聚合条件如聚合温度和单体浓度对最终聚合物的立构规整度的影响。还评估了柔性间隔基在可聚合基团和聚异氰酸酯模板之间的作用。其中可聚合基团在棒状螺旋多异氰酸酯主链上被分子调节的自由基聚合反应产生的乙烯基聚合物即使在溶液状态下也具有不可逆的立构规整度。

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