Hybrid PVA composites with basalt fiber and functionalized biocarbon: Mechanical strengthening and EMI shielding efficiency

The research explores the development and performance evaluation of polyvinyl alcohol (PVA) based composites reinforced with basalt fiber and silane treated biocarbon filler. The composites were fabricated using a hand lay-up technique and characterized for mechanical, dielectric, magnetic and electromagnetic interference (EMI) shielding properties. A progressive increase in reinforcement was employed across five composite formulations (P, PF, PFB1, PFB2 and PFB3) with varying biocarbon content. Among the fabricated specimens, PFB2 comprising 50 vol. % basalt fiber and 2 vol. % silane treated biocarbon demonstrated the best overall performance, with a tensile strength of 147 MPa, flexural strength of 163 MPa, impact energy of 5.0 J, shore-D hardness of 90, dielectric permittivity of 4.4, magnetic permeability of 4.30 and EMI shielding effectiveness of 65.92 dB. These enhancements are attributed to improved filler dispersion, optimized interfacial bonding and synergistic reinforcement effects from silane treatment. The results suggest that such hybrid composites are promising candidates for structural applications requiring superior mechanical integrity, dielectric behaviour and EMI shielding efficiency.