High-Performance Multifunctional Shape Memory Epoxy with Hybrid Graphene Oxide and Carbon Nanotube Reinforcement

This work investigates the design and development of multifunctional shape memory polymers (SMP) with significantly improved mechanical and thermal properties and uniquely tunable damping properties. Graphene oxide (GO) and single-walled carbon nanotube (CNT) nanofillers, known for their remarkable mechanical, thermal, and electrical properties, are systematically dispersed into a thermoset SMP using a solvent solution with sonication. SMP specimens of varying nanofiller ratio compositions are studied to determine the individual and combined contributions of GOs and CNTs. Remarkably, the nanofiller ratio determined the tradeoff between improvements in SMP stiffness and toughness. The results showed significant improvements in tensile and mechanical properties resulting from favorable nanofiller network dynamics that impeded crack propagation under quasistatic loading. Micrographs were obtained using a confocal laser scanning microscope (CLM) to investigate the dispersion characteristics. These micrographs in conjunction with fractography results obtained using CLM and scanning electron microscopy (SEM) were used to investigate fracture surfaces under various nanofiller compositions. Further study using dynamic mechanical analysis (DMA) showed improvements in storage modulus and glass transition temperatures, owing to improvements in the resin network brought on by the interactions of carbon-based nanofillers in the SMP matrix. The results reveal important information on the optimum combinations of the nanofillers in the SMP matrix that enable improved mechanical and thermal properties.