有机纤维/EPDM绝热材料性能研究

通过对腈纶短纤维、芳纶短纤维各自用量对EPDM绝热层材料烧蚀速率、孔隙率影响的研究,并结合氮气环境下热失重曲线和炭层SEM照片分析,发现腈纶短纤维不仅高温残炭率高于芳纶短纤维,而且可在较宽的温度范围内逐步热解炭化,烧蚀过程所产生的热解气体能逐步而快速地释放出炭层,结炭层孔隙率小,致密坚硬,能抵抗高温燃气流的烧蚀和冲蚀作用,材料的烧蚀速率较低;芳纶短纤维虽然具有较高的热稳定性,但热分解温度范围较窄,热解所产生的大量气体很难快速释放出炭层表面,结炭层孔隙率大,炭层疏松且呈层片状,不能抵抗高冲蚀性粒子流的烧蚀和冲蚀,烧蚀速率较高。

Study on properties of organic fiber/EPDM heat-insulating material

The effects of polyacrylonitrile(PAN) fiber and aramid fiber content on ablative rate and charring-layer porosity of EPDM insulation were studied respectively.The thermogravimetric(TG) curves of PAN fiber and aramid fiber in nitrogen and the SEM of charring-layer were analyzed.The results show that not only carbon residue ratio of PAN fiber is higher than that of aramid fiber,but also PAN fiber can be gradually pyrolyzed and carbonized within the wide temperature range;pyrolysis gas during the ablative process can be released quickly from charring-layer;the porosity of charring-layer is smaller,and the charring-layer is so tight and hard that it can effectively resist ablation and erosion of high temperature combustion gas flow;the ablative rate of insulating material is smaller.On the contrary,though aramid fiber has higher thermal stability,its thermal decomposition temperature range is very narrow;pyrolysis gas can hardly be released from the charring-layer quickly;the porosity of charring-layer is higher;the charring-layer is loose and presents lamellar,which cannot effectively resist ablation and erosion of high temperature gas,and the ablative rate is higher.