The interlaminar toughness of carbon-fibre reinforced plastic composites using 'hybrid-toughened' matrices

The use of nano-SiO2 particles and rubbery particles to give 'hybrid-toughened' epoxy polymers has been analyzed to give a range of novel matrices which lead to an increased delamination toughness of the resulting CFRP composites by resin-transfer molding (RTM) and vacuum-assisted resin-transfer molding (VARTM). The rubbery particles magnificently increase the toughness of the material via interactions of the stress field ahead of the crack tip compared with the pure epoxy polymer. Both particles are introduced to give a multiphase 'hybrid-toughened' polymeric materials. The presence of a relatively high concentration of the nano-SiO2 toughening particles does not lead to a decrease in the modulus of the composite. These mechanisms will lead to further increases in the mechanical performance of 'hybrid-toughened' epoxy polymers, containing a complex multiphase structure of nano- and micro-sized phase inclusions.