Structural and mechanical characteristics of silane-modified PIPD/basalt hybrid fiber-reinforced polybenzoxazine composites

Typically, hybrid fibers reinforced composites have the potential to provide materials with excellent mechanical properties. However, cost-effective, lightweight, easily manufactured and high-performance materials are even more attractive for the market and the industry. In this work, newly designed hybrid poly-pyridobisimidazole (PIPD) and basalt fibers (BFs) reinforced polybenzoxazine composites were investigated. Initially, the fibers were chemically modified with silane GX-560 coupling agent. Afterwards, the hybrid combinations were included in the resin and cured. The Fourier transform infrared spectra showed the chemical bond that results when the silane is grafted. The X-ray photoelectron spectroscopy scan provided the fibers atomic content and showed that the silane content was effectively raised after treatment. The microhardness and impact properties were markedly improved, reaching the maximum value of 570 MPa and 18.44 kJ/m(2), respectively, compared to the reference resin with 347 MPa and 1.6 kJ/m(2). This was due to the high-performance PIPD and BFs inclusive of their good interfacial adhesion and scattering around the surface confirmed by the fibers' pull-out void and the random dispersion seen in the scanning electron microscope images.