定张力大剂量连续辐照对PAN纤维结构和热性能的变化研究

The structure and thermal properties changes of PAN fibers treated by continuous high-dose irradiation at constant tension

在空气气氛、定张力和兆戈瑞级的大剂量下,采用电子束对碳纤维前驱体聚丙烯腈纤维(PAN)进行连续辐照处理。采用凝胶含量、电子顺磁共振波谱、红外光谱等手段研究辐照后PAN纤维结构变化,联合差示扫描量热仪和热失重研究辐照后PAN的热性能变化。辐照后PAN纤维主要发生交联,凝胶含量为90%。辐照会引起PAN纤维表面温度升高,加速自由基反应,辐照引发PAN纤维的环化或脱氢反应,形成C=C或C=N共轭新结构,能显著降低环化放热峰的强度,并缓和放热行为。兆戈瑞大剂量下PAN纤维的失重率由27%降低为17%,显著提高了PAN纤维的热稳定性。定张力下大剂量辐照PAN纤维能有利于碳纤维性能的提升,具有重要的学术意义和应用价值。

The polyacrylontirle(PAN)fibers were irradiated continuously to the high doses of MGy under fixed tension in air by electron beam.Gel fraction,electron spin resonance and infrared spectrum were applied to investigate the structural changes of PAN fibers after irradiation.Changes in the thermal properties of irradiated PAN fibers were studied combined differential scanning calorimeter with thermal gravimetric analysis.Cross-linking was dominant and the gel fraction attained 90%.Irradiation induced temperature rise on the surface of PAN fibers and promoted the free radical reaction.Cyclization or dehydrogenation reactions induced by irradiation formed C=C or C=N conjuated structures,which obviously decreased the intensity of cyclization exothermic peak and mitigated the exothermic behaviors.The weight loss decreased from 27%to 17%after irradiation at a high dose of MGy for PAN fibers and promoted the thermal stability.It is favorable to the improvement of carbon fiber performance for PAN fibers irradiated to high dose under fixed tension.It has important academic significance and application value.