Simultaneously reinforcing and toughening of polylactide/carbon fiber composites via adding small amount of soft poly(ether)urethane

Bio-degradable polylactide (PLA) based composites has attracted much attention both in academic research and industrial applications in recent decades due to the increasing environmental concerns. In this work, we tried to obtain PLA based composites with good stiffness-toughness balanced properties by adjusting carbon fiber (CF) network in polylactide (PLA) matrix via adding a small amount of soft poly(ether)urethane (PU). It was interesting to find that PU could serve as “solder” to weld CF into a more perfect network due to the fact that PU has stronger interaction with CF as compared with PLA and improve the interface interaction between CF and PLA meanwhile. The self-weld CF network structure was confirmed by SEM characterizations, rheology and conductivity tests. More importantly, the formation of self-weld network structure constructed by both stiff CF and ductile PU elastomer can simultaneously improve tensile strength, impact toughness and even electrical conductivity of PLA. This inspiring result demonstrates that the addition of soft elastomer which has a strong interaction with fiber into fiber-reinforced polymers could be a universal platform to improve the performance of polymer composites via tuning fibers network and the interfacial interaction between fibers and polymer matrix.