To improve the transparency and tensile properties of immiscible poly(methyl methacrylate) (PMMA) and ethylene-vinyl alcohol copolymer (EVOH) blended films, lithium (trifluoromethane sulfonyl) imide (LiTFSI) was added in small amounts. The addition of LiTFSI improved the transparencies of the PMMA/EVOH blends. However, scanning electron microscopy (SEM) images revealed that the blends with LiTFSI still maintained a sea-island morphology of the PMMA and EVOH phases with strong interfacial adhesion. A comparison of the SEM and energy-dispersive X-ray spectroscopy (EDS) images revealed the localization of LiTFSI in the EVOH domains. By comparing the refractive index data for the EVOH/LiTFSI blends, we established that the refractive indexes of the EVOH phases at LiTFSI concentrations of 20 or 30 wt% matched that of pure PMMA, which accounted for the improvement in transparency. The localization of LiTFSI interrupted the intra- and intermolecular hydrogen bonds of the OH groups in EVOH, resulting in a decrease in crystallinity. Consequently, the amorphous and flexible EVOH domains dispersed in the PMMA matrix prevented stress concentration during tensile deformation, improving the tensile properties.

为了提高不混溶的聚甲基丙烯酸甲酯（PMMA）和乙烯-乙烯醇共聚物（EVOH）共混薄膜的透明度和拉伸性能，添加了少量的（三氟甲磺酰）酰亚胺锂（LiTFSI）。LiTFSI 的添加提高了 PMMA/EVOH 共混物的透明度。然而，扫描电子显微镜 (SEM) 图像显示，与 LiTFSI 的共混物仍然保持了 PMMA 和 EVOH 相的海岛形貌，具有很强的界面粘附力。SEM 和能量色散 X 射线光谱 (EDS) 图像的比较揭示了 LiTFSI 在 EVOH 域中的定位。通过比较 EVOH/LiTFSI 共混物的折射率数据，我们确定 LiTFSI 浓度为 20 或 30 wt% 时，EVOH 相的折射率与纯 PMMA 的折射率相匹配，这就是透明度提高的原因。LiTFSI的局部化破坏了EVOH中OH基团的分子内和分子间氢键，导致结晶度降低。因此，分散在 PMMA 基体中的无定形柔性 EVOH 域可防止拉伸变形过程中的应力集中，从而提高拉伸性能。