Understanding on the structure and dynamics of poly(vinyl acetal)s is insufficient due to the complicated chemical structure and amorphous nature of this type of polymers. In this work, we investigate the effect of side group length on structure and dynamics heterogeneity at different length scales spanning from side group, segment, and polymer network by combing dynamic mechanical analysis (DMA), dielectric relaxation spectroscopy (DRS), solid-state NMR, and differential scanning calorimetry analysis (DSC). By increasing the length of acetal side group, its intrinsic dynamics slows down. Taking into account the scale of segment and networks, with the increase of acetal group length, the formation of cross-linking sites formed by the hydroxyl-rich domain is suppressed, the relaxation distribution of the segment widens, and the volume fraction of rigid component decreases. The effect of side group length on the structure and dynamics heterogeneity of poly(vinyl acetal)s at different scales results in significant changes in material properties such as the non-monotonic change in loss factor value (tan δ) and a monotonous reduction in glass transition temperature (T_g).

由于此类聚合物的复杂化学结构和无定形性质，对聚（乙烯醇缩醛）的结构和动力学的了解还不够。在这项工作中，我们通过结合动态力学分析（DMA）、介电弛豫光谱（DRS）、固态材料，研究了侧基长度对侧基、链段和聚合物网络不同长度尺度上的结构和动力学异质性的影响。 NMR 和差示扫描量热分析 (DSC)。通过增加缩醛侧基的长度，其内在动力学减慢。考虑到链段和网络的规模，随着缩醛基团长度的增加，富羟基域形成的交联位点的形成受到抑制，链段的松弛分布变宽，刚性组分的体积分数减少。侧基长度对不同尺度聚乙烯醇缩醛结构和动力学异质性的影响导致材料性能发生显着变化，例如损耗因子值（tanδ）的非单调变化和玻璃的单调减少转变温度（T _g）。