热氧化处理时间对芳纶纤维表面聚集态结构和性能的影响

Effect of Thermal Oxidation Treatment Time on Surface Aggregation Structure and Properties of Aramid Fiber

在250℃条件下以空气氧化热处理改性芳纶纤维,通过红外光谱(FTIR)、Raman光谱、X射线衍射(XRD)、扫描电子显微镜(SEM)研究了热氧化处理时间对芳纶纤维表面基团和聚集态结构的影响。FTIR结果表明,热处理过程中纤维表面皮层分子链重排,氢键重构,100 min的热处理时间能够使纤维表层的分子链重新排列取向完成,延长处理时间对表层结晶度影响不大。XRD研究表明芳纶纤维热处理60 min后结晶度达到最大,继续延长热处理时间纤维表层的含氧量变化并不明显。芳纶纤维在250℃条件下一定时间热处理对纤维的单丝拉伸强度影响并不明显,热处理热120 min,芳纶纤维的单丝拉伸强度为24.5 cN/dtex,与原丝相比提升了约3%。250℃热处理60 min后芳纶纤维与环氧树脂微滴间界面剪切强度增加到18.05 MPa,与原丝相比增加了11.9%。

The aramid fiber was modified by air oxidation heat treatment at 250℃with different time,and the influence of thermal oxidation treatment time on the surface group and aggregation structure of aramid fiber was studied by infrared spectroscopy(FTIR),Raman spectroscopy,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM).FTIR results show that the molecular chains rearrange on the surface of the fiber in the process of heat treatment,the hydrogen bond reconstructs,and the molecular chains on the surface of the fiber could rearrange and oriented after 100 min,and the extension of the treatment time has little influence on the surface crystallinity.XRD and XPS studies show that the crystallinity of aramid fiber reaches the maximum after 60 min heat treatment,and the change of oxygen content in the surface layer of the fiber is not obvious when the heat treatment time is prolonged.Under the condition of 250℃,the single filament tensile strength of aramid fiber is not significantly affected by the heat treatment for a certain time.After 120 min of heat treatment,the single filament tensile strength is 24.5 cN/dtex,which increases nearly 3%comparing with the original filament.After heat treatment at 250℃for 60 min,the interfacial shear strength of aramid fiber and epoxy resin microdroplet increase to 18.05 MPa,which is 11.9%higher than that of the original filament.