Inter- and intramolecular interactions in multicomponent polymer systems influence their physical and chemical properties significantly and thus have implications on their synthesis and processing. In the present study, chemical images were obtained by plotting the peak position of a spectral band from the datasets generated by in-situ ATR-FTIR spectroscopic imaging. This approach was successfully used to visualize changes in intra- and intermolecular interactions in Poly(3-hydroxybutyrate)/Poly(L-lactic acid) (PHB/PLLA) blends during the isothermal melt crystallization. The peak position of ν (C=O) band, which reflects the nature of the intermolecular interaction, shows that the intermolecular interactions between PHB and PLLA in the miscible state (1733 cm-1) changes to the inter- and intramolecular interaction (CH3∙∙∙O=C, 1720 cm-1) within PHB crystal during the isothermal melt crystallization. Compared with spectroscopic images obtained by plotting the distribution of absorbance of spectral bands, which reveals the spatial distribution of blend components, the approach of plotting the peak position of a spectral band reflects the spatial distribution of different intra- and intermolecular interactions. With the process of isothermal melt-crystallization, the disappearance of the intermolecular interaction between PHB and PLLA and the appearance of the inter- and intramolecular interactions within the PHB crystal were both visualized through the images based on the observation of the band position. This work shows the potential of using in-situ ATR-FTIR spectroscopic imaging to visualize different types of inter- or intramolecular interactions between polymer molecules or between polymer and other additives in various types of multicomponent polymer systems.

 

多组分聚合物系统中的分子间和分子内相互作用显着影响其物理和化学性质，从而对其合成和加工产生影响。在本研究中，化学图像是通过从原位 ATR-FTIR 光谱成像生成的数据集中绘制光谱带的峰值位置来获得的。这种方法已成功用于可视化等温熔融结晶过程中聚（3-羟基丁酸酯）/聚（L-乳酸）（PHB/PLLA）共混物中分子内和分子间相互作用的变化。λ (C=O) 带的峰值位置反映了分子间相互作用的性质，表明处于混溶状态 (1733 cm-1) 的 PHB 和 PLLA 之间的分子间相互作用变为分子间和分子内相互作用 (CH3â ??????????????O=C, 1720 cm-1) 在等温熔融结晶过程中 PHB 晶体内。与通过绘制光谱带吸光度分布获得的光谱图像相比，它揭示了混合组分的空间分布，绘制光谱带峰值位置的方法反映了不同分子内和分子间相互作用的空间分布。随着等温熔融结晶过程，PHB和PLLA之间的分子间相互作用的消失和PHB晶体内分子间和分子内相互作用的出现都通过基于带位置观察的图像可视化。

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