Studies on mechanical and fracture properties of basalt/E-glass fiber reinforced vinyl ester hybrid composites

In this study, a comparative analysis of basalt, E-glass and hybrid fiber reinforced vinyl ester composites was carried out. Composites were fabricated using vacuum infusion process with 0 degrees/90 degrees and +/- 45 degrees as fiber orientation angles. The influence of volume fraction on mechanical behaviors and surface morphology of impact fractured composites were analyzed. The glass and basalt fibers oriented at 0 degrees have shown higher load bearing capability, whereas the fibers oriented at 45 degrees angle have shown higher plastic deformation. Hybridized composite having silane treated glass fibers has shown enhanced mechanical properties including tensile strength, bending strength, toughness, and elongation at break due to good bonding between fibers and polymer matrix. The tough and flexible interface between fiber and matrix dissipates more energy through stress transfer from matrix to fiber, allowing increased resistance to shearing. The impact test of BGS-0.2 hybrid composite showed 103% and 108% of strength improvement compared to basalt (B-0) and glass fiber (G-0) reinforced laminates, respectively. However, the fiber orientation at 45 degree showed reduced the strength and modulus with high elongation. The fractography micrographs of hybrid composites have shown the effectiveness of basalt and glass fiber orientation in the composites and bonding between fiber and matrix indicating flexible interphase between the fiber and matrix during impact loading. The composites added with silane have shown marginal increase in water uptake due to presence of polar functional groups in the coupling agent.