Nanosized Hybrid Polymer Modifiers (HPM) for Improved Mechanical and Thermal Behavior of Carbon Fiber Reinforced Composites

Lightweight carbon fiber-reinforced polymer composites are replacing metallic components due to improved strength-to- weight ratios and fatigue resistance. However, they crack and delaminate due to low-velocity impact reducing their mechanical properties. Some of the approaches include surface modification of carbon fibers and addition of graphene or graphene oxide nanoparticles, improving resistance to crack propagation and reduces delamination. Graphene oxide (GO) can achieve excellent dispersion with polymer matrices due to functional groups compatible with composite matrix systems. Prior research from our group demonstrated successful grafting of GO with polyhedral oligomeric silsesquioxane (POSS) to optimize the thermal stability of GO. Due to cage-like structure of POSS, dispersion of these hybrid nanoparticles within polymer matrices could result in an enhancement in mechanical and thermal behavior of composite materials. Methacryl polyhedral oligomeric silsesquioxanes (MAPOSS) molecules were hybridized to GO to MEGO and characterized. The dispersion of HPM was studied in thermoset resin system Epon 862 Epoxy. In addition, the effect of HPM on polymer and carbon fiber reinforced polymer composite were studied. Results confirmed that the addition of HPM at very low wt.% can enhance the viscoelastic, mechanical, and thermal properties of composites. The presence of MEGO enhanced the interlaminar fracture toughness by ~ 70% at 0.5% MEGO loading without drastically affecting the strength and modulus, as confirmed by SEM images.