The effects of tetrahydrofuran (THF) on the physical properties of poly(methyl methacrylate) at (PMMA)/silica nanoparticle interfaces in polymer nanocomposites were investigated via differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) analysis. Amorphous structures containing PMMA chains with large numbers of trans-gauche conformers were observed in the annealed samples. The amorphous structures in the samples cast from THF suspensions contained PMMA chains rich in trans–trans conformers. These amorphous structures differed from those of neat PMMA prepared without silica. Although the polymer chain mobility was reduced due to interactions between PMMA and the silica nanoparticles, trans–trans-enriched PMMA chains within the amorphous structures were less affected by these interactions. When the amorphous structures were heated above the glass transition temperature of PMMA, the proportion of trans–gauche conformers increased. When the neat PMMA samples were dried at room temperature, the glass transition temperature ( T g ) increases linearly with the decrease in the amount of residual solvent. However, even if the residual solvent is extrapolated to 0 wt%, the T g is significantly lower than the bulk T g despite no residual solvent. The T g of heat-dried samples heat treated at 120 °C also increases linearly with decreasing residual solvent content. However, T g was significantly different depending on the drying temperature even with the same residual solvent amount. These results indicated that the PMMA samples dried at room temperature have a distinctly different molecular mobility from the heated sample.

中文翻译：

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四氢呋喃对聚合物纳米复合材料界面区域聚甲基丙烯酸甲酯和二氧化硅的影响

通过差示扫描量热法 (DSC)、傅里叶变换红外 (FT-IR) 光谱和 X 光谱法研究了四氢呋喃 (THF) 对聚合物纳米复合材料 (PMMA)/二氧化硅纳米颗粒界面处聚甲基丙烯酸甲酯物理性质的影响-射线衍射（XRD）分析。在退火样品中观察到包含具有大量反式构象异构体的 PMMA 链的无定形结构。从 THF 悬浮液浇铸的样品中的无定形结构包含富含反式-反式构象异构体的 PMMA 链。这些无定形结构不同于没有二氧化硅制备的纯 PMMA。尽管由于 PMMA 和二氧化硅纳米粒子之间的相互作用，聚合物链的流动性降低，无定形结构内的反式-反式富集 PMMA 链受这些相互作用的影响较小。当无定形结构被加热到高于 PMMA 的玻璃化转变温度时，trans-gauche 构象异构体的比例增加。当纯 PMMA 样品在室温下干燥时，玻璃化转变温度 (T g ) 随着残留溶剂量的减少而线性增加。然而，即使残留溶剂外推到 0 wt%，尽管没有残留溶剂，T g 仍显着低于本体 T g。在 120 °C 下热处理的热干燥样品的 T g 也随着残留溶剂含量的降低而线性增加。然而，即使残留溶剂量相同，T g 也因干燥温度而显着不同。