Effect of Benzoxazine on Epoxy Based Carbon Fabric Reinforced Composites for High Strength Applications

Abstract

Benzoxazine (BZ) is novel class of thermoset polymers exhibiting tailor-made properties in a wide range of structural applications especially in aerospace industries. When BZ is used as hybrid resin in composite preparation, it offers attractive mechanical properties. An attempt was made with combination of DGEBA epoxy resin and an aromatic diamine hardener with different weight proportions of BZ 2, 4, 6, 8 and 10% reinforced with PAN-based carbon fabric, in order to study the mechanical characteristics. The weight proportions of BZ enhanced the properties of tensile strength, Flexural strength and inter-laminar shear strength (ILSS) due to strong interfacial adhesion between fabric and hybrid resin system. The studies reveal that 4% of BZ-reinforced composites possess better properties than those of the reference neat epoxy–amine matrix and other weight percentages of composites. In this study, the mechanical, thermal properties of the hybrid were compared with reference epoxy–amine matrix composite. Optical microscope images ascertain the existence of homogeneous distribution of benzoxazine in the composites. The Glass transition temperature (Tg) was determined by Dynamic Mechanical Analyzer (DMA) technique reveals lowering of Tg in hybrid due to off-stoichiometry by the incorporation of BZ. However, post-curing of the composite enhanced both mechanical and thermal properties.