磷酸二氢铵对聚丙烯腈纤维预氧化程度及热稳定性的影响  

Effect of ammonium dihydrogen phosphate on pre-oxidation degree and thermal stability of polyacrylonitrile fiber

作　　者：支环 苏哲安[1] 黄启忠[1] 戴开斌 徐平[1] Zhi Huan;Su Zhe-an;Huang Qi-zhong;Dai Kai-bin;Xu Ping(National Key Laboratory of Science and Technology on High-strength Structural Materials,Central South University,Hunan Changsha 410083,China)

机构地区：[1]中南大学轻质高强结构材料重点实验室,湖南长沙410083

出　　处：《炭素技术》2021年第4期49-55,共7页Carbon Techniques

摘　　要：聚丙烯腈(PAN)纤维的预氧化过程是PAN基炭纤维生产中最耗能耗时的阶段。为了加快PAN纤维的预氧化过程,提高PAN纤维的预氧化程度,采用非金属化合物磷酸二氢铵(NH4H2PO4)对PAN纤维进行改性,探讨了磷酸二氢铵对PAN纤维化学结构和热性能的影响。通过傅里叶红外光谱(FT-IR)和X射线衍射(XRD)分析得到,PAN纤维的预氧化程度随着预氧化温度和试验设定的NH4H2PO4浓度范围内升高而升高。与未改性PAN纤维相比,相同温度下,改性PAN纤维环化度更高,在180℃和200℃低温条件下更为明显,240℃及260℃的促进效果一般,另外改性PAN纤维在240℃可提前完成环化反应。热重(TGA)结果表明,NH4H2PO4受热分解产生的磷酸与羟基反应导致分子链交联,能降低预氧化过程中的热失重,提高热稳定性。The pre-oxidation process of polyacrylonitrile(PAN) fiber is the most energy-consuming and time-consuming stage in the production of PAN-based carbon fiber. In order to accelerate the pre-oxidation process and improve pre-oxidation degree, the nonmetallic compound ammonium dihydrogen phosphate(NH4 H2 PO4) is used to modify PAN-fiber, and the effect of ammonium dihydrogen phosphate on the chemical structure and thermal properties of PAN-fiber is explored. Fourier transform infrared spectroscopy(FT-IR) and X-ray diffraction(XRD) analysis show that the pre-oxidation degree of PAN-fiber increases with the increases of preoxidation temperature and NH4 H2 PO4 concentration. Compared with the unmodified PAN-fiber, the modified PAN-fiber has higher cyclization degree at the same temperature, which is more obvious at both 180 ℃ and 200 ℃, and the promotion effect at 240 ℃ and260 ℃ is general. Moreover, the cyclization reaction of the modified PAN-fiber could be completed in advance at 240 ℃. TGA results show that the reaction of phosphoric acid produced by thermal decomposition of ammonium dihydrogen phosphate with hydroxyl leads to cross-linking of molecular chains, which could reduce the thermal weight loss during pre-oxidation process and improve the thermal stability.

关 键 词：聚丙烯腈纤维 化学改性 预氧化反应 热稳定性 

分 类 号：TQ342.742[化学工程—化纤工业]