3D Printable high-strength aramid nanofiber reinforced composites via vat photopolymerization

초록

Aramid nanofiber (ANF) is effective reinforcement materials for polymer composites, but their integration into Vat photopolymerization (VP) resins requires careful optimization to maintain printability. In this study, a high-strength ANF-reinforced resin was developed for VP by introducing a structural restoration process. Rheological analysis showed that increasing ANF content substantially raised the yield stress and imparted pronounced shear-thinning behavior, which in Turn affected layer recoating and dimensional accuracy. The optimized formulation containing 0.2 wt% ANF achieved a tensile strength of 32.4 MPa and Young's modulus of 672 MPa, representing improvements of 187% and 168% over the neat resin, respectively. However, at higher ANF loading (0.3 wt%), the viscous, high yield stress resin required the use of a recoater to spread each layer, and micro-computed tomography (Micro-CT) revealed that this process introduced low sphericity voids within the printed parts. The presence of these voids corresponded with a reduction in mechanical properties at the higher nanofiber content. These results underscore the need to carefully optimize the ANF concentration (similar to 0.2 wt%) to maximize strength gains while preserving print fidelity. Overall, this study elucidates the effects of ANF incorporation on both printability and mechanical strength, and further identifies recoater-induced void formation at high ANF loadings as an additional factor limiting mechanical performance. These findings offer valuable guidance for designing VP nanocomposites that achieve both high strength and excellent printability.

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