用13CNMR研究聚甲基丙烯酸锡酯的立构序列分布

本文测定了自由基型溶液聚合的聚甲基丙烯酸三甲基锡酯(PTMTM),聚甲基丙烯酸三乙基锡酯(PTETM)和聚甲基丙烯酸三丁基锡酯(PTBTM)的¹³C-NMR谱,对其C-2谱扩展分峰,计算立构序列,从定量数据表明,聚合物样品的空间立构富于或稍富于间规立构,随取代基的体积增大而趋于无规分布,作者认为受空间位阻效应和分子内或分子间形成配位键的影响。     

^1H自旋扩散方法研究离子化聚氨酯的相态结构

本文用改进的Goldman-Shen脉冲序列研究了聚丁二烯加MDI离子化聚氨酯体系中磁化矢量的自旋扩散过程,通过一些合理的简化,求解了扩散方程,得到了一种可定量的求出多相高聚物微区尺寸的简便方法.     

聚氰丙基甲基硅氧烷-聚脲嵌段共聚物的NMR表征及研究

用高分辨NMR对聚甲基硅氧烷-聚脲嵌段共聚物以及聚氰丙基甲基硅氧烷-聚脲嵌段共聚物结构进行表征,对NH形成的各种氢键进行详细的研究,同时观察了氢键在力学性能中的作用,结果发现氢键强烈地影响着力学性能。用固体¹H宽线研究这类材料的相分离状况,并总结影响相分离的因素。保持硬段含量不变,增加软段分子量使相分离程度增加;保持软段分子量不变,增加硬段含量使相分离程度降低。软、硬段之间的相互作用(如氢键)使相分离程度降低。     

NMR STUDIES ON POLYETHER-POLYURETHANE ZWITTERIONOMERS——CHAIN STRUCTURE AND PHASE SEPARATION

The ~1H and ~(13)C NMR spectra of polyether-polyurethancs (A) based on 4, 4'-diphenylmethanediisocyanate (MDI), N-methyl diethanolamine (MDEA), and polytetramethyleneoxide (PTMO)and the zwitterionomers derived from A with various degree of ionization was assigned by comparingwith model compounds. Phase separation of the samples was visualized through pulsed NMR investigations. The FIDsignals of these multiphase elastomers were recorded and decomposed by non-linear least squaresregression into fast Gaussian and slow exponential components assodated with the hard, the soft andthe interface respectively. Thus pulsed NMR gives both qualitative and quantitative informationabout the existence of multiphases and the relative amounts of materials in each phase.     

NMR STUDY ON THE COMPATIBILITY OF ACR/PVC BLENDS

A 300MHz solid NMR study on the compatibility of ACR (poly (methyl methacrylate-co-methacrylate), in the ratio of 1:1)-PVC (poly (vinyl chloride)) blends is reported. Spin-lattice (T_1) and spin-spin (T_2) relaxation time of ACR, PVC and their blends are recorded in the temperature range from 215K to 355K. Experimental results indicate that ACR and PVC are compatible with each other and the domain size is smaller than 25 nm, but heterogeneit(?)s of molecular dimensions still exist. Some problems of mechanism of compatibility and data analysis are also discussed.     

A SOLID NMR STUDY OF POLYETHERESTER-UREAS

The morphology of some polyetherester-ureas were studied by ~(13)C CP/MAS and ~1H wide-line NMR spectroscopy. It was found that the HDI and MDI based polymers have well crystallized hard segments, whereas the TDI and HMDI based ones have not. For HDI/MDI based polymers, the presented results suggest that the distribution of two kinds of hard segment units is mainly in a block form. The influences of the different hard segment and chain length on the mobility of the soft segment were also studied.     

蓖麻油型聚氨酯IPN的结构与性能研究

本文用蓖麻油,甲苯二异氰酸酯和甲基丙烯酸β-羟乙酯组成的加聚型网络(Ⅰ)和蓖麻油,甲苯二异氰酸酯和聚丙二醇组成的缩聚型聚氨酯(Ⅱ),以同步法形成了一组新型的IPN。用动态力学法和固体核磁共振法研究了它们的结构和性能,形成IPN后,力学数据显示出机械强度的提高,动态力学损耗谱上表现出,tanδ的增宽,固体核磁共振谱计算的结果是界面层的比例增高,但界面层比例并不随配比的改变而变化,它揭示出此IPN可能具有壳核结构。     

SOLID-STATE VARIABLE-TEMPERATURE NMR STUDY ON THE PHASE SEPARATION OF POLYETHER POLYURETHANE ZWITTERIONOMERS

Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments.     

聚氰丙基甲基硅氧烷—聚脲嵌段共聚物的NMR表征及研究

用高分辨NMR对聚甲基硅氧烷-聚脲嵌段共聚物以及聚氰丙基甲基硅氧烷-聚脲嵌段共聚物结构进行表征,对NH形成的各种氢键进行详细的研究,同时观察了氢键在力学性能中的作用,结果发现氢键强烈地影响着力学性能。用固体~1H宽线研究这类材料的相分离状况,并总结影响相分离的因素。保持硬段含量不变,增加软段分子量使相分离程度增加;保持软段分子量不变,增加硬段含量使相分离程度降低。软、硬段之间的相互作用(如氢键)使相分离程度降低。     

聚苯乙烯/聚异戊二烯嵌段共聚物相态结构的固体核磁研究

本文将固体核磁中的交叉极化与魔角旋转(CP/MS)技术与Goldman-Shen脉冲序列相结合,研究了不同分子量的单分散聚苯乙烯/聚异戊二烯嵌段共聚物(SAI)中磁化矢量的自旋扩散速度。以一个均匀分布的相结构模型为基础,求解了扩散方程和样品中的微区尺寸。