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采用质量法、扫描电子显微镜(SEM)、体密度测试、元素分析(EA)、X射线衍射(XRD)及拉曼光谱(Raman)等手段,探究了高温处理过程PAN基碳纤维空隙结构的变化及其原因。结果表明:热处理过程存在组成元素的逸出及由化学变化和结构转化引起的纤维外形尺寸的变化,在其共同作用下,碳纤维的体密度在800~1500℃范围先增加后减少,在1000℃体密度出现最大值;碳、氢、氧和氮元素的质量减少,碳、氮元素的溢出,造成碳纤维骨架结构的不完整性,形成内部缺陷,且随着温度的升高,碳、氮元素脱除加剧,内部空隙结构增加;由于纤维表面氧含量相对较高,随着温度的升高,纤维表面氧含量脱除量加剧,碳纤维开孔的空隙结构增加,反映在随着温度的升高,碳纤维体密度和表观体密度的差异增大。
The changes of the pore structure of PAN-based carbon fiber were investigated by means of mass spectrometry, scanning electron microscopy (SEM), bulk density measurement, elemental analysis (EA), X-ray diffraction (XRD) and Raman spectroscopy. The reason. The results show that there exists the escape of the components and the changes of the fiber shape caused by the chemical and structural transformations. The bulk density of the carbon fiber increases first and then decreases from 800 ℃ to 1500 ℃ under 1000 ℃ The maximum of body density appeared, the quality of carbon, hydrogen, oxygen and nitrogen decreased, the overflow of carbon and nitrogen, caused the incomplete structure of carbon fiber skeleton and formed internal defects. With the increase of temperature, the carbon and nitrogen With the increase of the temperature, the removal of oxygen content on the surface of the fiber is exacerbated, and the void structure of the carbon fiber pore is increased, which is reflected in the increase of the temperature as the temperature increases , The difference between the carbon fiber bulk density and the apparent bulk density increases.