Structural change of st-PMMA on drawing, absorption and desorption of solvents
Structural change of st-PMMA on drawing, absorption and desorption of solvents
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St-PMMA在溶剂吸收、吸收和解吸过程中的结构变化
DOI：
10.1016/0032-3861(82)90263-4
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发表时间：
1982
期刊：
影响因子：
4.6
通讯作者：
H. Tadokoro
中科院分区：
文献类型：
--
作者：
Hideo Kusuyama;M. Takase;Yoshihide Higashihata;H. Tseng;Y. Chatani;H. Tadokoro
以氯丙酮、二乙基甲酮等为溶剂，采用溶剂诱导结晶法从拉伸非晶样品中制备了取向良好的间规聚甲基丙烯酸甲酯（st-PMMA）结晶样品。这些样品的X-射线纤维图通常显示35.4 π的周期，也表明st-PMMA链具有大半径和小轴向节距的螺旋构象，沿沿着原始拉伸方向。在结晶过程中，这是一个很大的变化的链的取向的指示，这是一个大的螺旋构象的大部分红外吸收带的二向色性反转，再次支持。还证实了溶剂对于保持结晶度是必要的，因为样品在溶剂解吸时失去结晶度。根据这些结果，可以想象st-PMMA与溶剂形成类似于公知的直链淀粉-碘络合物的络合物。
Well-oriented crystalline samples of syndiotactic poly(methylmethacrylate) (st-PMMA) could be prepared from stretched non-crystalline samples on solvent-induced crystallization using chloroacetone, diethyl ketone, etc. as the solvent. X-ray fibre diagrams of these samples usually show period of 35.4Å and also suggest that the st-PMMA chains have a helical conformation of large radius and small axial pitch along the original stretched direction. Inversion of dichroism for most infra-red absorption bands during the crystallization, which is an indication of a wide variation in the orientation of the chains, again supports the large helical conformation. It was also confirmed that the solvents are necessary in maintaining the crystalinity as the samples lose crystallinity on desorption of the solvents. From these results, it is conceivable that st-PMMA forms a complex with the solvents similar to the well-known amylose-iodine complex.