Enhanced Interfacial Integrity for Chain Growth Polymer Carbon Fiber Composites via Surface-Initiated Polymerization

The interface between carbon fiber (CF) and a polymer matrix is critical for the transfer of load in CF-reinforced polymer composites. Surface functionalization via covalently grafted molecules has been a successful strategy for enhancing the interfacial integrity of epoxy-based composites. In contrast, there has been limited application to composite resins based on chain-growth polymerization mechanisms, such as vinyl ester resins, due to challenges in their experimental evaluation. Here, we introduce a concept to systematically enhance and tailor the interfacial mechanical properties of these composites based on short, surface-grown polymers. All-atom molecular dynamics simulations reveal how the complexities of the cross-linking network, both among the surface-grown chains and between the surface chains to the bulk resin, are critical to securing a robust interfacial mechanical response under shear. These key traits, obtained from molecular-level insights, provide practical guidance for using surface-initiated polymerization to optimize the interface, expanding the range of applications for these challenging composites based on chain-growth resins.