Increasing the flame retardancy and cryogenic toughness of an epoxy polymer using polydopamine nanoparticles
Bingnong Jiang, Wenkai Chang, Xinyi Wang, Sha Zhao, Garth Pearce, L.R.F. Rose, A. J. Kinloch, Chunhui Wang
Abstract
Low fracture toughness , especially at cryogenic temperatures , and high flammability are two major factors limiting the application of epoxy-based fibre reinforced composites in extreme environments. In this study, we introduce a novel approach to addressing both challenges by incorporating polydopamine (PDA) nanoparticles as a multifunctional additive in epoxy matrices . PDA nanoparticles (200–250 nm), synthesised via the oxidative self-polymerization of dopamine, exhibit excellent compatibility with epoxy and can be uniformly dispersed at high loadings through probe sonication . Experimental and computational modelling results reveal that incorporating 10 wt% PDA nanoparticles yields remarkable improvements in fracture toughness and fire resistance: fracture energy increases by 520% at 23 °C and 610% at −196 °C, while peak and total heat release are reduced by 45% and 25%, respectively. These results demonstrate the dual functionality of PDA nanoparticles in simultaneously improving fracture toughness and flame retardancy. The findings of this work offer a significant advancement toward the development of fibre-reinforced composites capable of withstanding extreme thermomechanical conditions, with promising implications for cryogenic hydrogen storage in net-zero aviation and transport applications.