AbstractIn this work, pyridine ring and pendent tert‐butyl were introduced into the diamine NTPA in view of improving the processability and transparency of the PIs via inhibiting charge‐transfer complexes (CTCs). Meanwhile, the amide linkage was simultaneously introduced in order to boost the thermal and mechanical properties of the PIs by reasonably increasing the polymer stiffness via noncovalent amide H‐bonding. The dianhydride BPADA was employed in the copolymerization with the diamine comonomers of NTPA with ODA in different ratios. Due to the presence of tert‐butyl and pyridine ring, the synthesized co‐PIs showed good optical properties with T500 higher than 75% for all co‐PIs, reaching 83% for homopolymer BPADA‐NTPA, higher solubility in organic solvents, and better hydrophobicity with maximum hydrostatic contact angle as high as 91.9°. Meanwhile, the amide H‐bonding increased the mechanical properties of co‐PIs with the maximum tensile strength reaching 127 MPa. Furthermore, amide H‐bonding exceedingly offset the reducing effects of pendent bulky butyl groups on the thermal properties of PIs, and the Tg of the co‐PIs containing NTPA moiety ranged in 244–298°C, remarkably higher than 218°C for homopolymer BPADA‐ODA. This work proved cooperative synergistic effects of multiple functional groups in balancing the general properties of co‐PIs.
摘要 在这项研究中,为了通过抑制电荷转移络合物(CTCs)来改善聚对苯二甲酸乙二醇酯的可加工性和透明度,在二胺 NTPA 中引入了吡啶环和悬垂叔丁基。同时,为了通过非共价酰胺 H 键来合理增加聚合物的硬度,从而提高聚合绝缘体的热性能和机械性能,还引入了酰胺连接。二酐 BPADA 以不同的比例与二胺共聚物共聚,其中二胺共聚物为 NTPA 和 ODA。由于存在叔丁基环和吡啶环,合成的共 PI 具有良好的光学性能,所有共 PI 的 T500 值均高于 75%,均聚物 BPADA-NTPA 的 T500 值达到 83%,在有机溶剂中的溶解度更高,疏水性更好,最大静水接触角高达 91.9°。同时,酰胺 H 键增加了共聚合物的机械性能,最大拉伸强度达到 127 兆帕。此外,酰胺 H 键还极大地抵消了悬垂大丁基对 PI 热性能的降低作用,含有 NTPA 分子的共 PI 的 Tg 范围为 244-298°C,明显高于均聚物 BPADA-ODA 的 218°C。这项工作证明了多种官能团在平衡共 PI 一般特性方面的协同效应。