• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>RSC Advances >C-H center dot center dot center dot O (ether) hydrogen bonding along the (110) direction in polyglycolic acid studied by infrared spectroscopy, wide-angle X-ray diffraction, quantum chemical calculations and natural bond orbital calculations
【24h】

C-H center dot center dot center dot O (ether) hydrogen bonding along the (110) direction in polyglycolic acid studied by infrared spectroscopy, wide-angle X-ray diffraction, quantum chemical calculations and natural bond orbital calculations

机译：C-H中心点中心点中心点O（乙醚）沿（110）方向氢粘接在用红外光谱，广角X射线衍射，量子化学计算和天然键轨道计算研究的聚乙醇酸中

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

Polyglycolic acid (PGA), a biodegradable polyester with a simple molecular structure, shows an abnormally high melting point of 220 degrees C which is the highest among biopolyesters. In order to investigate this peculiar physical property and the structure of PGA, its temperature-dependent infrared (IR) spectra and wide angle X-ray diffraction (WAXD) were measured. Of note in the IR spectra is that among the many bands, those due to antisymmetric and symmetric CH2 stretching modes and that due to the C-O-C stretching mode show a significantly lower wavenumber shift with temperature increase. These experimental results suggest the existence of weak C-H center dot center dot center dot O (ether) hydrogen bonding along the (110) direction in PGA. WAXD results support this suggestion by an observed noticeable decrease of a unit cell length along the (110) direction. The natural bond orbital (NBO) calculations indicate there is weak intermolecular bonding between the C-H bond of the CH2 group and the oxygen atom of the -C-O-C- linkage. The quantum chemical calculations of the IR spectra were carried out for models of PGA based on the crystalline structure by using a partial optimization in the normal mode. The results can qualitatively explain the observed temperature dependence of the CH2 stretching modes of PGA, which is due to weakening of the C-H center dot center dot center dot O interactions among polymer chains with a temperature increase. All the experimental and theoretical calculation results suggest that there is weak hydrogen bonding between the CH2 group and the ether oxygen atom. This intermolecular interaction may be the cause for the abnormally high melting point of PGA.
机译：聚乙醇酸（PGA），可生物降解的聚酯通过简单的分子结构，示出的220摄氏度，其是生物聚酯中是最高的异常高的熔点。为了调查这种奇特的物理性质和PGA的结构中，它的温度依赖性的红外（IR）光谱和广角X射线衍射（WAXD）测定。注意在IR光谱的是，许多频带中，由于C-O-C伸缩模式的那些由于反对称和对称伸缩CH2模式和表现出与温度上升一个显著低波数偏移。这些实验结果表明沿PGA（110）方向弱C-H中心点中心的点中心的点O（乙醚）氢键的存在。 WAXD结果支持由沿（110）方向上的单元电池的长度的观察明显减少这个建议。自然键轨道（NBO）计算表明存在CH 2基团的C-H键和-C-O-C-键的氧原子之间的弱分子间键合。红外光谱的量子化学计算系为在正常模式下使用的局部优化基于该结晶结构PGA的模型进行。结果可以定性解释PGA，这是的CH2拉伸模式中的观察到的温度依赖性由于随着温度上升的聚合物链之间的C-H中心点中心的点中心的点直径：相互作用的弱化。所有的实验和理论计算的结果表明，有CH 2基团和醚氧原子之间的弱氢键。此分子间相互作用可以是用于PGA的异常高的熔点的原因。

著录项

  • 来源
    《RSC Advances》 |2016年第20期|共7页
  • 作者

    Sato Harumi; Miyada Mai; Yamamoto Shigeki; Reddy Kummetha Raghunatha; Ozaki Yukihiro;

  • 作者单位

    Kobe Univ Grad Sch Human Dev &

    Environm Nada Ku Kobe Hyogo 6578501 Japan;

    Kwansei Gakuin Univ Sch Sci &

    Technol Dept Chem Sanda Hyogo 6691337 Japan;

    Osaka Univ Grad Sch Sci Dept Chem Toyonaka Osaka 5600043 Japan;

    Kwansei Gakuin Univ Sch Sci &

    Technol Dept Chem Sanda Hyogo 6691337 Japan;

    Kwansei Gakuin Univ Sch Sci &

    Technol Dept Chem Sanda Hyogo 6691337 Japan;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

相似文献

  • 外文文献
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