• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Applied Polymer Science >Structural investigations of acrylonitrile-vinyl acid copolymers by NMR Spectroscopy
【24h】

Structural investigations of acrylonitrile-vinyl acid copolymers by NMR Spectroscopy

机译：NMR光谱法研究丙烯腈-乙烯酸共聚物的结构

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

H-1, C-13 [H-1]-, and 2D HETCOR NMR spectroscopy have been employed to characterize polyacrylonitrile (PAN) homopolymer and copolymers of methacrylic acid (MAA) and itaconic acid (IA) prepared by solvent-water suspension polymerization technique in a mixture containing DMF (solvent) and water. The chemical composition of P(AN-MAA) copolymers was determined using H-1-NMR and that of P(ANAA) using quantitative C-13[H-1] NMR spectra. P(ANAA) copolymers show two separate signals due to two carboxylic groups in different magnetic environments of IA, whereas P(AN-MAA) shows only one in the region of delta 6.32-7.60 ppm in H-1-NMR and delta 171.0-176.0 ppm in C-13[H-1]-NMR spectra. Evidence of acrylamide formation by the partial hydrolysis of AN groups is obtained by the small broad signal at delta 7.9 ppm in H-1-NMR spectra. No carboxylic proton signal was observed in copolymers containing 12 mol% of comonomer, which indicates the formation of anhydride. The microstructure was obtained in terms of the A- and M-centered triad sequences from C-13 [H-1]-and H-1-NMR spectra of the copolymers, which showed configurational and compositional sequences. For example, at higher comonomer content, the concentration of AAM and AAI sequencing increases. This is confirmed by 2D HETCOR NMR spectra also. The distribution of AN sequences is found to be random (n(o) similar to n(m) similar or equal to 2.0). The tacticity values are not affected by the comonomer content. The isotacticity remained almost same at 27% (mm, 26.5-29.3) in all acrylonitrile polymers irrespective of the nature of the comonomer and polymerization medium, that is, DMF/H2O ratio. (C) 2003 Wiley Periodicals, Inc. [References: 18]
机译：H-1，C-13 [H-1]-和二维HETCOR NMR光谱已用于表征聚丙烯腈（PAN）均聚物以及通过溶剂-水悬浮聚合制备的甲基丙烯酸（MAA）和衣康酸（IA）的共聚物技术在含有DMF（溶剂）和水的混合物中使用。使用H-1-NMR确定P（AN-MAA）共聚物的化学组成，并使用定量C-13 [H-1] NMR光谱确定P（ANAA）的化学组成。 P（ANAA）共聚物由于在IA的不同磁性环境中存在两个羧基而显示出两个独立的信号，而P（AN-MAA）在H-1-NMR和Delta 171.0-中仅在δ6.32-7.60 ppm区域显示一个在C-13 [H-1] -NMR谱中为176.0ppm。通过H-1-NMR光谱中δ7.9 ppm处的小宽峰信号，可以得到AN基团部分水解形成丙烯酰胺的证据。在含有12mol％共聚单体的共聚物中未观察到羧基质子信号，这表明形成酸酐。根据共聚物的C-13 [H-1]-和H-1-NMR谱图，以A-和M-中心的三单元组序列表示了微观结构，该图显示了结构和组成序列。例如，在较高的共聚单体含量下，AAM和AAI测序的浓度增加。这也通过2 HETCOR NMR光谱得到了证实。发现AN序列的分布是随机的（n（o）类似于n（m）相似或等于2.0）。规整度值不受共聚单体含量的影响。不论共聚单体和聚合介质的性质如何，即DMF / H2O的比例，所有丙烯腈聚合物的等规度几乎都保持在27％（mm，26.5-29.3）。 （C）2003 Wiley Periodicals，Inc. [参考：18]

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号