Micro-hardness behavior of fiber reinforced thermosetting composites embedded with cellulose nanocrystals

Abstract

The influences of Nano particles incorporation, fiber type and matrix types on the mechanical properties of fiber-reinforced composites have been widely investigated by researchers. However, the effects of targeted fiber arrangements on the micro-hardness properties of bulk polymeric-based composites have not yet been studied. This study aims at assessing the influence of fiber arrangement as well as the incorporation of Nano particles, on Vickers micro-hardness properties of glass fiber-reinforced polymers (GFRP). Five types of samples were prepared: unreinforced (UR) polyester, bulk reinforced arranged (BRA) composite, surface reinforced arranged (SRA) composite, Nano Polyester (NP) and Nano Glass-fiber reinforced composite (NGFRP). Cellulose nanocrystals were uniformly dispersed using an ultrasonic processor. Characterization has been performed using micro-hardness tester. The experimental results demonstrate that a significant increase was observed in micro-hardness values of SRA and BRA specimens subjected to indentation forces with respect to UR samples. The optimum incorporation percentage of cellulose nanocrystals was found to be 4% by weight, which leads to the highest values of micro-hardness. The fiber arrangement and optimum incorporation percentage of Nano particles have shown promising micro-hardness results, aiming for quality improvement and cost reduction. Keywords: Micro-hardness, Surface reinforcement, Glass fiber-reinforced plastic, Vickers hardness, Resin transfer molding