Development of novel high Tg polyimide-based composites. Part II: Mechanical characterisation

In this study, the mechanical performance assessment of a newly developed carbon fibre-reinforced polyimide composite system T650/NEXIMID (R) MHT-R is presented. This system was subjected to a series of mechanical tests at ambient and elevated temperature (320?) to determine basic material properties. Moreover, an additional test was conducted, using a T650/NEXIMID (R) MHT-R laminate in which the fibre sizing was thermally removed prior to laminate manufacturing, to investigate the effect of fibre treatment on mechanical performance. The experimental results indicated that the T650/NEXIMID (R) MHT-R composites along with exceptionally high T-g (360-420?) exhibited competitive mechanical properties to other commercially available polyimide and epoxy-based systems. At elevated temperature, the fibre-dominated properties were not affected whilst the properties defined by matrix and fibre/matrix interface were degraded by approximately 20-30%. Finally, the fibre sizing removal did not affect the tensile and compressive strength, however, the shear strength obtained from short-beam shear test was deteriorated by approximately 15%.