A para-aramid fiber whose main chain contained heterocyclic units was prepared by low temperature copolycondensation, wet-spinning, and high temperature thermal treatment. The prepared fibers (named F-368) and two commercial aramid fibers, K49 (Kevlar 49, Dupont de Nemours Co., USA) and APMOC (Kamenskvolokno and Tver’khimvolokno, Russia), were characterized and analyzed in detail. Infrared spectroscopy (IR) and wide-angle X-ray diffraction (WAXD) were employed to characterize their chemical and aggregation structures, respectively. The results showed the introduction of heterocyclic units into the wholly para-aromatic polyamide backbone of K49 in the F-368 and APMOC reduced the crystallinity significantly. The tenacity of F-368 and APMOC were 32.2 and 30.5cN/dtex, which were about 68% and 59% higher than that of K49, respectively. Thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) were used to investigate their thermal properties; the results indicated that these aramid fibers showed exceptional thermal properties with glass transition temperatures of 240–260 °C, and decomposition temperatures at 510–560 °C, both in nitrogen and air. The TGA results also showed the decomposition mechanism of K49 and the heterocyclic aramid fibers in nitrogen and air were different. The decomposition temperature of K49 was higher than that of the heterocyclic copolyaramid fibers both in nitrogen and air. On the contrary, the char yields of the heterocyclic copolyaramid fibers at 800 °C were higher than that of K49 in both nitrogen and air.

通过低温共聚，湿纺和高温热处理制备主链包含杂环单元的对位芳族聚酰胺纤维。对制得的纤维（命名为F-368）和两种商用芳纶纤维K49（美国Dupont de Nemours公司的Kevlar 49）和APMOC（俄罗斯Kamenskvolokno和Tver'khimvolokno）进行了详细表征和分析。分别采用红外光谱（IR）和广角X射线衍射（WAXD）表征其化学结构和聚集结构。结果表明，在F-368和APMOC中，将杂环单元引入K49的全对位芳族聚酰胺骨架中会显着降低结晶度。F-368和APMOC的强度分别为32.2和30.5cN / dtex，分别比K49高68％和59％。用热重分析（TGA）和动态力学分析（DMA）研究它们的热性能。结果表明，这些芳族聚酰胺纤维在氮气和空气中均具有出色的热性能，玻璃化转变温度为240–260°C，分解温度为510–560°C。TGA结果还表明，K49的分解机理与杂环芳族聚酰胺纤维在氮气和空气中的分解机理不同。在氮气和空气中，K49的分解温度均高于杂环共聚芳族聚酰胺纤维的分解温度。相反，在氮气和空气中，杂环共聚芳酰胺纤维在800°C时的炭收率均高于K49。结果表明，这些芳族聚酰胺纤维在氮气和空气中均具有出色的热性能，玻璃化转变温度为240–260°C，分解温度为510–560°C。TGA结果还表明，K49的分解机理与杂环芳族聚酰胺纤维在氮气和空气中的分解机理不同。在氮气和空气中，K49的分解温度均高于杂环共聚芳族聚酰胺纤维的分解温度。相反，在氮气和空气中，杂环共聚芳酰胺纤维在800°C时的炭收率均高于K49。结果表明，这些芳族聚酰胺纤维在氮气和空气中均具有出色的热性能，玻璃化转变温度为240–260°C，分解温度为510–560°C。TGA结果还表明，K49的分解机理与杂环芳族聚酰胺纤维在氮气和空气中的分解机理不同。在氮气和空气中，K49的分解温度均高于杂环共聚芳族聚酰胺纤维的分解温度。相反，在氮气和空气中，杂环共聚芳酰胺纤维在800°C时的炭收率均高于K49。TGA结果还表明，K49的分解机理与杂环芳族聚酰胺纤维在氮气和空气中的分解机理不同。在氮气和空气中，K49的分解温度均高于杂环共聚芳族聚酰胺纤维的分解温度。相反，在氮气和空气中，杂环共聚芳酰胺纤维在800°C时的炭收率均高于K49。TGA结果还表明，K49的分解机理与杂环芳族聚酰胺纤维在氮气和空气中的分解机理不同。在氮气和空气中，K49的分解温度均高于杂环共聚芳族聚酰胺纤维的分解温度。相反，在氮气和空气中，杂环共聚芳酰胺纤维在800°C时的炭收率均高于K49。