Preparation and properties of isotactic and syndiotactic poly(methyl methacrylate)s, uniform with respect to molecular weight
Preparation and properties of isotactic and syndiotactic poly(methyl methacrylate)s, uniform with respect to molecular weight
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分子量均匀的等规和间规聚甲基丙烯酸甲酯的制备和性能
DOI：
10.1002/masy.19940850125
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
N. Miyatake
中科院分区：
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作者：
K. Hatada;K. Ute;T. Kitayama;Takafumi Nishiura;N. Miyatake
用超临界流体色谱柱(SFC)分离了相对分子质量均一的高度等规聚间规聚甲基丙烯酸甲酯S(PMMA)，并用核磁共振和质谱仪对其进行了表征。均一的it-PMMA和St-PMMA的玻璃化转变温度(Tg‘s)平均高于具有MWD的PMMA的玻璃化转变温度(Tg’s)，而相对分子质量相近的PMMA的玻璃化转变温度(Tg‘s)较低。均一的it-和St-PMMAs系列的Tg符合关系式Tg=Tg∞-K/M，其中M和Tg∞分别表示分子量和无限大M处的Tg。通过挥发溶剂从甲醇溶液中得到了均一的聚合度为28-44的it-PMMA，其倒数熔点(1/Tm)随1/Dp的增加而线性增加。将线性关系外推到1/DP=0，得到了无限大DP的聚甲基丙烯酸甲酯的Tm；Tm∞=171.1°C。在凝胶渗透色谱(GPC)测定中，It-50mer的洗脱速度比st-50mer快。用一系列均匀的PMMA可以得到it-PMMA和St-PMMA的校准曲线。当样品溶液体积为0.003ml时，用该仪器测定的仪器展开率为0.070毫升。对it-和st-50在四氢呋喃中的混合物的GPC分析表明，在溶液中形成了立体络合物，并发现这对阐明形成络合物所需的最小序列长度非常有用。
Highly isotactic (it-) and highly syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) uniform with respect to molecular weight (stereoregular, uniform PMMAs) were isolated up to the 100mer from it- and st-PMMAs by supercritical fluid chromatography (SFC) and characterized by NMR and mass spectroscopies. Glass transition temperatures (Tg's) of the uniform it- and st-PMMAs were higher than those of the corresponding PMMAs with MWD and with similar molecular weight on average. The Tg values of the uniform it-and st-PMMAs series obeyed the relationship, Tg = Tg∞ - K/M, where M and Tg∞ denote molecular weight and Tg at infinite M, respectively. The reciprocal melting points (1/Tm) of uniform it-PMMA (degree of polymerization, DP = 28–44), obtained from methanol solutions by evaporating the solvent, increased linearly with increasing 1/DP. Extrapolation of the linear relation to 1/DP = 0 gave the Tm of it-PMMA with infinite DP; Tm∞ = 171.1°C. Thermal degradation behavior was studied by thermogravimetry and by SFC analysis of degradation products. In gel-permeation chromatography (GPC) measurements, the it-50mer eluted faster than the st-50mer. Calibration curves for it- and st-PMMAs could be obtained using series of the uniform PMMAs. The instrumental spreading factor determined using it-25mer, it-50mer, st-25mer and st-50mer for our GPC chromatograph was 0.070 ml when the volume of the sample solution was 0.003ml. GPC analysis of a mixture of the it- and st-50mers in tetrahydrofuran indicated formation of a stereocomplex in the solution, and was found quite useful to elucidate the minimum sequence length required for complex formation.
Koichi Ute、Nobuo Miyatake、Yasuko Osugi、Koichi Hatada：“用制备型 SFC 分馏获得的甲基丙烯酸甲酯的等规和间规五聚物（50 聚体）：50 聚体及其立体复合物的 GPC 分析”Polym.J.25。
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Koichi Hatada、Koichi Ute、Tohru Nishimura、Masaharu Kashiyama、Toshinori Saito 和 Makoto Takeuchi：“甲基丙烯酸甲酯的立构规整低聚物。4. MMA 的等规和间规低聚物的超临界流体色谱法”聚合物子弹
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Koichi Ute、Nobuo Miyatake、Takeshi Asada、Koichi Hatada：“甲基丙烯酸甲酯的立体规则低聚物 6。通过制备超临界流体色谱法分离 19mer 至 29mer 的等规和间规 MMA 低聚物”Polym.Bull.28。
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