Interlaminar microstructure and mechanical response of 3D robust glass fabric-polyester composites modified with carbon nanofibers

The present work explores new methodology of fabricating the polymer nanocomposite with improved interlaminar, dynamic and micro mechanical properties. Varying amount of carbon nanofibers (CNF) were filled into the glass fiber/unsaturated polyester composite using filtering membrane vacuum-assisted method. Microporous nylon membrane was used to improve the dispersion of CNF in the lamination panels. CNF reinforcement and its concentration had a significant effect on the properties of the composites. Electron microscopy studies on delamination and nanofillers dispersion showed improved interfacial adhesion with CNF filled composites. The end-notched flexure and short-beam strength tests were performed to assess the effect of filling CNF on the interlaminar fracture properties of the composites. Existence of critical concentration was observed for the reinforcement of nanofiller. The properties of the composite enhance with increase in reinforcement upto critical concentration, beyond which it decreases. Better storage modulus (∼57%) and improved interlaminar properties (∼89%) were consistently observed with 2 wt% CNF filled nanocomposite irrespective of the glass fiber loading, besides, the thermal stability and char yield which were also improved significantly. Nanoindentation study shows 39% and 26% increase in elastic modulus and hardness of the composite respectively, on reinforcement of 2 wt% CNF.

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