高分子量聚丙烯腈纤维热稳定化过程中结构及性能演变

Structural evolution and chemical changes of PAN fibers during thermal stabilization

为了研究预氧化工艺对高分子量聚丙烯腈纤维结构和性能的影响,分别利用FTIR、广角X射线衍射仪、差式扫描量热仪及单丝强度细度仪等表征手段,通过对不同预氧化温度和时间下纤维的化学组成、晶体结构的演变、热稳定性、拉伸强度和模量的变化的研究,考察了预氧化工艺对纤维结构及性能演变的影响。研究发现,随着热稳定化温度的升高或稳定时间的延长,纤维原先线性分子链转变成环状结构部分增加,氰基组分残留率降低,纤维整体结晶度下降,结晶尺寸减小,热稳定性和碳化收率增加,纤维强度、模量逐渐降低。

In order to disclose the relationships of chemical changes and properties evolution with thermal stabilized time and temperature of high molecular polyacrylonitrile fibers,FTIR,WAXS,DSC and electronic tensile tester have been used to examine the chemical composition,crystal structure,thermal stabilization,tensile strength and initial modulus,respectively.The results showed that formal linear polymer chains gradually transformed into ladder structure.During the process,the amount of residual cyano component,crystal size and crystallinity decreased dues to the ordered structures were destroyed with increasing stabilization time or temperature.The thermal stabilization increased due to the ladder structure could enable fibers to obtain high-temperature resistance.Meanwhile,mechanical properties which were related to the cyano component decreased.