Preparation and characterization of chain-extended bismaleimide/carbon fibre composites

This paper presents an experimental study of the influence of the addition of aromatic diamine (MDA) to bismaleimide (BMI) resin on the crystallinity, solubility, melting temperature, and mechanical properties of BMI/carbon composites. The modified BMI was prepared through the chain extension with MDA via Michael addition reaction with molar ratio of 3:2 (BMI:MDA). Both modified and unmodified BMI were characterised for chemical structure, crystallinity, melting temperature, mechanical property, and morphology and fracture behaviour using FTIR, XRD, DSC, UTM, and SEM, respectively. The FTIR results revealed the formation of polymeric chain due to the broad N-H absorption. The modified resin was semicrystalline in nature having low melting temperature and hence showed good processibility. The modification of BMI resulted in decrease of pores and increase of tensile, flexural, and impact properties of the composites. Also, SEM studies of the tensile fractured specimens revealed that modification of BMI resulted in improved resin/fibre interfacial strength