In this paper, we present a synthetic strategy for N-phenyl substituted benzimidazole-derived diamines, including 2-(4-(4-aminophenoxy) phenyl)-1-phenyl-1H-benzo[d]imidazole-5-amine (para-diamine) and 2-(3-(4-aminophenoxy) phenyl)-1-phenyl-1H-benzo[d]imidazole-5-amine (meta-diamine). Two distinct series of N-phenyl substituted poly (benzimidazole imide)s (PBIPIs) were synthesized via reaction with different aromatic dianhydrides. The simulation reveals distinct amine reaction activities of two diamine monomers. The obtained PBIPIs exhibit exceptional heat resistance attributed to N-phenyl substituted benzimidazole (BI). The temperature at which weight loss of 5 % (T) is in the range of 491–595 °C under N environment, while the glass transition temperature is 237–329 °C. The PBIPIs exhibit specific solubility characteristics due to the flexible ether linkage groups' non-coplanarity and bulky pendant benzene groups. The PBIPIs possess tensile strength between 108 and 142 MPa, a tensile modulus of 4.0–5.9 GPa, and an elongation at a break of 4.2–26.4 %, indicating excellent mechanical properties. Additionally, the PBIPI with controlled molecular weight generated from BPADA incorporating 2-(3-(4-aminophenoxy) phenyl)-1-phenyl-1H-benzo[d]imidazole-5-amine (B-BPADA-PA) demonstrates exceptional melt processability. B-BPADA-PA possesses remarkable melt stability since its minimum complex viscosity is only 2100 Pa⋅s at 400 °C, and its melt viscosity ratio is 1.34 at 380 °C.

中文翻译：

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N-苯基苯并咪唑可溶高耐热热加工聚苯并咪唑酰亚胺的制备及表征

在本文中，我们提出了N-苯基取代的苯并咪唑衍生二胺的合成策略，包括2-(4-(4-氨基苯氧基)苯基)-1-苯基-1H-苯并[d]咪唑-5-胺(对-二胺）和2-（3-（4-氨基苯氧基）苯基）-1-苯基-1H-苯并[d]咪唑-5-胺（间二胺）。通过与不同的芳香族二酐反应合成了两个不同系列的N-苯基取代的聚苯并咪唑酰亚胺（PBIPIs）。模拟揭示了两种二胺单体的不同胺反应活性。由于 N-苯基取代的苯并咪唑 (BI)，所得 PBIPI 表现出优异的耐热性。 N环境下失重5%（T）的温度范围为491-595℃，玻璃化转变温度为237-329℃。由于柔性醚连接基团的非共面性和庞大的苯侧基，PBIPI 表现出特定的溶解度特征。 PBIPI 的拉伸强度为 108 至 142 MPa，拉伸模量为 4.0-5.9 GPa，断裂伸长率为 4.2-26.4%，表现出优异的机械性能。此外，由掺有 2-(3-(4-氨基苯氧基)苯基)-1-苯基-1H-苯并[d]咪唑-5-胺 (B-BPADA-PA) 的 BPADA 生成的具有受控分子量的 PBIPI 表现出出色的熔体可加工性。 B-BPADA-PA具有卓越的熔体稳定性，400℃时其最小复数粘度仅为2100Pa·s，380℃时熔体粘度比为1.34。