Structural changes and crystallization dynamics of poly(L-lactide) during the cold-crystallization process investigated by infrared and two-dimensional infrared correlation spectroscopy
Structural changes and crystallization dynamics of poly(L-lactide) during the cold-crystallization process investigated by infrared and two-dimensional infrared correlation spectroscopy
复制标题
DOI：
10.1021/ma049288t
复制
发表时间：
2004-08-24
期刊：
影响因子：
5.5
通讯作者：
Ozaki, Y
中科院分区：
文献类型：
--
作者：
Zhang, JM;Tsuji, H;Ozaki, Y
利用红外光谱和二维相关分析研究了聚l -丙交酯（PLLA）在等温冷结晶过程中的结构演变和结晶动力学。在C=O拉伸区，由于C=O基团之间的偶极-偶极相互作用，PLLA在结晶过程中发生了更高波数的带移。在波段高度重叠的1500-1000厘米（-1）范围内进行了详细的分析。发现1458 cm（-1）的波段反映了CH3基团的结构顺序，1109 cm（-1）的波段与PLLA晶相中的C-O-C反式构象有关。1193 cm（-1）处的波段不仅对C-O-C主链的结构调整敏感，而且对结晶相中CH3基团的结构顺序也敏感。从1500 ~ 1000 cm（-1）区域的差谱和二维相关谱分析可以看出，CH3基团的结构调整明显先于酯基团。此外，通过差谱分析研究了PLLA的详细结晶动力学。
The structural evolution and crystallization dynamics of poly(L-lactide) (PLLA) during isothermal cold-crystallization process are studied by infrared (IR) spectroscopy and two-dimensional correlation analysis. In the C=O stretching region, the band shift to a higher wavenumber taking place during the crystallization of PLLA is attributed to the dipole-dipole interaction between the C=O groups. A detailed analysis is performed for the range of 1500-1000 cm(-1) where bands are highly overlapped. It was found that the 1458 cm(-1) band reflects the structural order of the CH3 group, and the band at 1109 cm(-1) is related to the C-O-C trans conformation in the crystalline phase of PLLA. The band at 1193 cm(-1) is sensitive not only to the structural adjustment of the C-O-C backbone but also to the structural order of CH3 group in crystalline phase. From the analysis of the difference spectra and 2D correlation spectra in the 1500-1000 cm(-1) region, it is shown that the structural adjustment of the CH3 group unambiguously precedes that of the ester group. Moreover, the detailed crystallization kinetic of PLLA is investigated by analyzing difference spectra.