国产低导热PAN基碳纤维制备及其在绝热材料的应用

Preparation of home-made polyacrylonitrile carbon fibers with low thermal conductivity and its application in thermal insulation composites

为拓展碳纤维在绝热材料领域的应用,将实验室自制原丝通过低温炭化工艺制备得到了低导热聚丙烯腈(PAN)基碳纤维,分析了该碳纤维的化学组成、微观结构、表面形貌、热性能和力学性能等;并制备了低导热碳纤维增强酚醛树脂橡胶基绝热材料,探讨其热性能和烧蚀性能的变化规律和影响因素。结果表明,采用低温炭化,碳纤维的碳元素含量和结晶度相对较低,导致其热性能和力学性能较差,其中热导率最大可比MT300碳纤维降低46.9%,但有利于绝热材料的制备。炭化温度为900℃时,碳纤维绝热材料的热导率比MT300碳纤维绝热材料降低23.4%,线烧蚀率提高39.5%。该材料的制备工艺及关键性能参数可为国产碳纤维在固体火箭发动机内热防护领域的应用提供借鉴和参考。

To expand the application of carbon fibers in thermal insulation material field,we prepared PAN-based carbon fibers with low thermal conductivity through a low temperature carbonization technology by employing home-made polyacrylonitrile(PAN)carbon fibers as the precursor.The chemical composition,surface morphology,microstructure and thermal/mechanical properties were investigated systematically.After that,the corresponding carbon fiber reinforced thermal insulation composites were fabricated,and the effect of low-conductive fiber on the thermal and ablation performances was studied.The results indicates that,with the drop of carbonization temperature,the element content of carbon and graphitization degree for the carbon fibers could be reduced,resulting in degraded thermal/mechanical properties.The thermal conductivity was lowered by 46.9%in maximum than the commercialized MT300 carbon fiber,which is beneficial for the performance enhancement of insulation material.In addition,compared with that of the MT300 carbon fiber reinforced composite,the insulation composite reinforced by the fibers with a carbonization temperature of 900℃presents a decrease of 23.4%in thermal conductivity and a elevation in liner ablation rate up to 39.5%.The fabrication technology and the key performance parameters of this kind of composites will provide valuable references for the application of home-made PAN carbon fibers in thermal protection system of solid rocket engines.