热氧化对PAN基碳纤维结构与性能的影响

将PAN基碳纤维在于400~700℃条件下空气中进行热氧化处理,然后利用扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、密度梯度管和纤维强力仪研究了其表面化学组成、表面形貌与性能的变化。结果表明:热氧化温度低于600℃时,纤维表面含氧量随热氧化温度升高不断增加,到600℃时氧含量增加了7.11%,主要增加的官能团为羟基、醚键以及羰基,纤维体密度、线密度随热氧化温度变化不明显;700℃时由于含氧官能团的裂解,氧含量有所减少,裂解部分主要为羰基,纤维体密度明显增加,线密度急剧减小;纤维强度随热氧化温度升高不断减小,600℃后减小趋势更加明显;模量随热氧化温度变化不明显。

Effect of thermal oxidation on the structure and properties of PAN-based carbon fibers

A PAN-based carbon fiber was thermally oxidized in air at temperatures from 400 to 700℃. The chemical composition at the surface, the surface morphology, and the tensile properties of the resulting carbon fibers were investigated by scanning electron microscopy (SEM) , X-ray photoelectron spectroscopy (XPS), density measurements and fiber strength tests. The results showed that the oxygen content on the surface of the carbon fiber increased with increasing temperature of the treatment up to 600℃, with the oxygen content increasing by 7.11% at 600℃. The major functional groups on the surface of the thermally oxidized carbon fibers were hydroxyl, ether and carbonyl groups, and the density and line density of the carbon fiber showed a negligible change with increasing treatment temperature. On further heating to 700℃, the oxygen content decreased due to pyrolysis of carbonyl groups, whilst the density of the carbon fiber increased and the line density decreased significantly. The tensile strength of the fibers decreased with increasing thermal oxidation temperature, and the decrease became more marked above 600℃. The tensile modulus showed a negligible change with thermal oxidation temperature.