Shinzawa Hideyuki, Mizukado Junji
National Institute of Advanced Industrial Science and Technology (AIST), Japan.
National Institute of Advanced Industrial Science and Technology (AIST), Japan.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Jun 15;181:1-6. doi: 10.1016/j.saa.2017.03.026. Epub 2017 Mar 14.
Near infrared (NIR) imaging data of poly(lactic) acid (PLA) nanocomposite were analysed by disrelation mapping to prove the possible interaction between PLA matrix and montmorillonite-based nanoclay. The basic concept of disrelation mapping can be viewed as a spatial filter based on two-dimensional (2D) correlation function to elucidate specific areas where disrelated variation between intensities occurs. Correlation intensity develops on disrelation map only if spectral intensities at v and v within the local spatial area vary in a dissimilar manner. This feature is especially suitable for identifying the area where interaction between components occurs, which is not fully detected by the conventional visualizations based on a single wavenumber. Disrelation maps constructed with NIR bands arising from the crystalline and amorphous components of the PLA. The pattern appearing on the disrelation map indicated different distributions of the crystalline and amorphous components of the nanocomposite sample. In addition, the development of disrelation intensity becomes acute especially at the area adjacent to the clay, revealing that the clay essentially works as nucleating agent to cause the additional development of crystalline structure of PLA by lowering the surface energy barrier.
通过去相关映射分析聚乳酸（PLA）纳米复合材料的近红外（NIR）成像数据，以证明PLA基体与蒙脱土基纳米黏土之间可能存在的相互作用。去相关映射的基本概念可被视为基于二维（2D）相关函数的空间滤波器，用于阐明强度之间出现不相关变化的特定区域。只有当局部空间区域内ν和ν处的光谱强度以不同方式变化时，相关强度才会在去相关映射上显现。此特性特别适用于识别组分之间发生相互作用的区域，而基于单个波数的传统可视化方法无法完全检测到该区域。利用PLA结晶和非晶组分产生的近红外波段构建去相关映射。去相关映射上出现的图案表明了纳米复合材料样品中结晶和非晶组分的不同分布。此外，去相关强度的变化尤其在靠近黏土的区域变得明显，这表明黏土本质上起到了成核剂的作用，通过降低表面能垒促使PLA晶体结构进一步发展。
