Designing the microstructural architecture of bioinspired hierarchical hybrid nanocomposites

This study focuses on investigating the microstructural architecture of bioinspired hierarchical graphene nanoplatelets-(GnPs) and glass fiber-(GF) reinforced polypropylene-based hybrid composites and its impact on mechanical performance. A novel approach to control the self-assembly behavior of hierarchically structured fibrous reinforcements is presented, achieved by tailoring the surface chemistry of the GFs to optimize the density of covalently bonded GnPs. Structure-property relationships were established by comparing the GnP bonding density on the GFs and degree of trans-crystallization as a function of amino-surface modification with the mechanical performance of the fabricated composites. Tailoring the microstructural architecture can significantly improve the mechanical properties of these hybrid composites, due to improved stress transfer at the interface. This improvement arises from the increased interfacial area of the hierarchically structured hybrid reinforcement, which facilitates trans-crystalline growth at the interface. Additionally, the remaining un-bonded GnPs facilitate β-crystal nucleation in the bulk, improving the composite’s toughness. The hybrid composite with the highest GnP bonding density and the greatest degree of trans-crystallization demonstrates exceptional mechanical performance. Specifically, this hybrid composite exhibits an impact strength of ~ 63% greater than that without hierarchical reinforcement, along with tensile strength and toughness improvements of ~ 40% and ~ 77%, respectively.