仿“蔓根-墙体”形态构筑的PVDF-碳纤维一体结构增强的CFRP复合材料性能研究

Performance research on CFRP composites improved by PVDF-carbon fiber integrated structure by imitating vine root-wall morphology

  • 摘要: 为解决碳纤维增强树脂(CFRP)复合材料因层间粘接强度不足所引发的界面失效问题,提出仿照“蔓根-墙体”形态,采用静电纺丝技术在碳纤维布表面制备聚乙烯-co-马来酸酐共聚物(PEMA)改性的聚偏氟乙烯(PVDF)纤维,增强CFRP的弯曲性能。测试结果表明,所制备的PVDF纤维直径在数百纳米至数微米之间,呈现出无序排列形态,构建出一种半粘连的PVDF-碳纤维一体结构。当PVDF纤维面密度为0.12 g/m2时,复合材料的弯曲强度与能量吸收值相较于未增强试样分别提升了25.3%和31%。PVDF纤维的主干稳定性高而末端可自由移动,有利于形成纤维桥连结构。该结构能够优化富树脂区域(RRR)和界面过渡区(ITR),甚至贯穿相邻碳纤维层,从而构建出一种可抑制微裂纹产生与扩展的三维互锁结构,促使复合材料的失效模式由分层主导的失效转变为准剪切失效。

     

    Abstract: To address interlaminar bonding strength deficiencies and interfacial failure in carbon fiber reinforced polymer (CFRP) composites, this study aimed to improve the flexural properties of CFRP via electrospinning polyvinylidene fluoride (PVDF) fibers modified with polyethylene-co-maleic anhydride (PEMA) onto carbon fiber fabric by imitating vine root-wall morphology. Testing results showed that the prepared PVDF fibers had diameters ranging from several hundred nanometers to a few micrometers. These fibers displayed a randomly oriented morphology and formed a semi-bonded, integrated PVDF–carbon fiber structure. At a PVDF areal density of 0.12 g/m2, the composite exhibited a 25.3% increase in flexural strength and a 31% improvement in energy absorption compared to the unreinforced sample. The PVDF fibers featured stable backbones with freely movable ends, which promoted the formation of a fiber bridging architecture. This structure optimized the resin-rich regions (RRR) and the interfacial transition region (ITR), and could even penetrate adjacent carbon fiber layers. Thus, a three-dimensional interlocking structure was created, which effectively suppressed the initiation and propagation of microcracks. The failure mode shifted from delamination-dominated failure to quasi-shear failure.

     

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