溶胶配比对碳纤维增强炭气凝胶隔热复合材料力学性能的影响

以异丙醇(I)为溶剂、 六次甲基四胺(H)为催化剂, 配制间苯二酚(R)-糠醛(F)的醇溶胶, 经浸渍纤维预制件、凝胶老化、超临界干燥和炭化制得碳纤维增强炭气凝胶隔热复合材料。研究了溶胶配比对碳纤维增强炭气凝胶隔热复合材料密度、微观结构和力学性能的影响规律。结果表明:随着异丙醇与间苯二酚物质的量之比增大, 碳纤维增强炭气凝胶隔热复合材料的密度逐渐降低, 基体炭气凝胶内及与碳纤维形成的界面内孔径增大, 大孔数量增多, 碳纤维增强炭气凝胶隔热复合材料的强度降低。当异丙醇与间苯二酚物质的量之比由18增加到28时, 压缩强度由2.498 MPa(应变10%)降至0.716 MPa(应变10%), 拉伸强度由2.019 MPa降至1.001 MPa, 弯曲强度由3.984 MPa降至1.818 MPa。随着六次甲基四胺与间苯二酚物质的量之比增大, 碳纤维增强炭气凝胶隔热复合材料的密度先增大后减小, 基体炭气凝胶内及与碳纤维形成的界面内孔径先减小后增大, 大孔数量先减少后增加, 碳纤维增强炭气凝胶隔热复合材料的强度先增大后减小。当六次甲基四胺与间苯二酚物质的量之比为0.008 5时, 碳纤维增强炭气凝胶隔热复合材料的密度最大, 强度最大, 其压缩强度为1.066 MPa(应变10%), 拉伸强度为1.256 MPa, 弯曲强度为3.556 MPa。 

Effects of sol proportion on mechanical properties of carbon fiber reinforced carbon aerogel insulation composites

Carbon fiber reinforced carbon aerogel composites were prepared by impregnating the fiber preform,gel aging,supercritical drying and carbonization.Resorcinol (R)-furfural (F)alcohol sol was synthesized by isopro-panol (I)as solvent,hexamethylenetetramine (H)as catalyst.The effects of sol proportion on densities,micro-structures and mechanical properties of carbon fiber reinforced carbon aerogel insulation composites were investiga-ted.The results show that the densities of carbon fiber reinforced carbon aerogel insulation composites decrease gradually,the pores diameter and the amount of large pores in matrix carbon aerogels and the interface formed with carbon fiber increase,the strength of carbon fiber reinforced carbon aerogel insulation composites decreases with the increases of amount of substance ratio for isopropanol and resorcinol.When isopropanol and resorcinol amount of substance ratio increases from 18 to 28,the compressive strength decreases from 2.498 MPa (strain 10%)to 0.716 MPa (strain 10%),tensile strenghth decreases from 2.019 MPa to 1.001 MPa,bending strength decreases from 3.984 MPa to 1.818 MPa.The densities of carbon fiber reinforced carbon aerogel insulation composites increa-ses firstly and then decreases,the pores diameter and the the amount of large pores in matrix carbon aerogels and in-terface formed with carbon fiber decreases firstly and then increases,the strength of carbon fiber reinforced carbon aerogel insulation composites increases fistly and then decreases with the increase of amount of substance ratio for hexamethylenetetramine and resorcinol.The densities and the strength of carbon fiber reinforced carbon aerogel in-sulation composites are biggest when amount of substance ratio for hexamethylenetetramine and resorcinol is 0.008 5,the compressive strength is 1.066 MPa (strain 10%),the tensile strenghth is 1.256 MPa,bending strength is 3.5 5 6 MPa.