Conformation Rearrangement and Molecular Dynamics of Poly(3-hydroxybutyrate) during the Melt-Crystallization Process Investigated by Infrared and Two-Dimensional Infrared Correlation Spectroscopy
Conformation Rearrangement and Molecular Dynamics of Poly(3-hydroxybutyrate) during the Melt-Crystallization Process Investigated by Infrared and Two-Dimensional Infrared Correlation Spectroscopy
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DOI：
10.1021/ma0501343
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发表时间：
2005-04
期刊：
影响因子：
5.5
通讯作者：
Jianming Zhang;Harumi Sato;I. Noda;Y. Ozaki
中科院分区：
文献类型：
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作者：
Jianming Zhang;Harumi Sato;I. Noda;Y. Ozaki
采用差谱、二阶导数和二维相关分析等方法，研究了聚3-羟基丁酸酯（PHB）在等温熔融结晶过程中不同波数区（C-H、CO、C-O-C和C-C伸缩振动区）的红外光谱随时间的变化，确定了各区中结晶和非结晶部分的特征谱带。通过二维相关分析，发现1731 cm-1带中的强度变化（可能是由于中间态）和1722 cm-1带中的强度变化（由于晶体堆积）彼此异相发生，而在两个无定形CO伸缩带中的那些（1747和1739 cm-1）归因于主链的不同构象是同步的，其代表在结晶过程中处于非晶态的CO基团的协同构象重排。同时，在118波段的强度变化率之间存在明显的延迟。
Time-dependent infrared (IR) spectral variations during isothermal melt-crystallization process of poly(3-hydroxybutyrate) (PHB) have been analyzed for different wavenumber regions (C−H, CO, C−O−C, and C−C stretching vibration regions) by difference spectra, second derivatives, and two-dimensional (2D) correlation analysis, and the bands characteristic of crystalline and amorphous parts are identified in each region. By the 2D correlation analysis, it has been found that the intensity changes in the 1731 cm-1 band, which may be due to the intermediate state, and in the 1722 cm-1 band due to the crystal packing occur out of phase with each other, whereas those in the two amorphous CO stretching bands (1747 and 1739 cm-1) ascribed to the different conformations of the main chain are synchronous, which represents a cooperative conformational rearrangement for the CO groups in the amorphous state during the crystallization process. Meanwhile, a distinct delay between the intensity change rates of bands at 118...