文章通过超临界CO₂辅助溶液浸渍法，以聚酰胺酸（PAA）和缩水甘油多面体倍半硅氧烷（POSS）改性芳纶纤维，以改性芳纶纤维制备芳纶纤维/炭黑/丁苯橡胶复合材料（AF/CB/SBR=2/50/100），测试改性芳纶纤维对复合材料加工性能的影响，并研究两种表面接枝处理剂对AF/CB/SBR复合材料性能的影响。结果表明：超临界CO₂辅助POSS、PAA改性处理后，复合材料的交联密度增加明显，延迟了橡胶的硫化过程，正硫化时间增加。两种改性均能提升改性纤维与橡胶间的界面黏结，超临界CO₂辅助POSS改性后复合材料的拉伸强度、100%定伸分别提升10.77%、19.58%，而超临界CO₂辅助PAA改性后复合材料的拉伸强度、100%定伸分别提升15.13%、25.77%。相应地，超临界CO₂辅助POSS、PAA改性后，改性芳纶纤维与丁苯橡胶界面滑脱能数值分别为5.76、6.94，分别增加17.6%和41.6%，相比较而言，经大分子PAA接枝改性后芳纶纤维对橡胶复合材料综合性能的提升较为有利。

In this paper, the aramid fiber was modified with polyamic acid (PAA) and glycidyl polyhedral sesquioxane (POSS) by supercritical CO₂ assisted solution impregnation method, and then aramid fiber/carbon black/styrene-butadiene rubber composites (AF/CB/SBR=2/50/100) were prepared by modified aramid fiber. The effects of modified aramid fibers on the processing performance of composites were tested and the effects of two surface grafting agents on the performance of AF/CB/SBR composites were investigated. The results showed that the crosslinking density of the composites increased significantly after the modification of POSS and PAA with supercritical CO₂, which delayed the vulcanization process and increased the positive vulcanization time. The tensile strength and 100% constant elongation of the composites modified by supercritical CO₂-assisted POSS increased by 10.77% and 19.58%, respectively, while the tensile strength and 100% constant elongation of the composites modified by supercritical CO₂-assisted PAA increased by 15.13% and 25.77%, respectively. Correspondingly, after the modification of POSS and PAA assisted by supercritical CO₂, the interface slip energy values were 5.76 and 6.94, increasing by 17.6% and 41.6%, respectively. In comparison, the aramid fiber modified by macromolecule PAA grafting is more favorable to the improvement of the comprehensive properties of rubber composites.