Establishing interphase with “rigid-flexible coupling” crosslinked network by supramolecular structure to improve interfacial properties of high-modulus carbon fiber composites

Interfacial properties are a key factor influencing the overall performance of carbon fiber reinforced polymer composites (CFRPs). A novel interphase with “rigid-flexible coupling” crosslinked network is established by introducing supramolecule pseudopolyrotaxane (PPR) on the high modulus carbon fiber (HMCF) surface to improve interfacial properties of CFRPs. Our design utilizes the unique molecular necklace structure of PPR composed of β-cyclodextrin (β-CD) and polyetheramine (PEA). Here, hydroxyl-rich β-CD acts as crosslinking sites and catalyst to enhance interfacial crosslinking density and the mobile main chain PEA serves as an internal stress relaxant to dissipate stress, thereby simultaneously improving the stiffness and toughness of the interphase. The resultant CFRPs exhibit excellent interfacial properties with a 90 % rise in interfacial shear strength (IFSS) and 156 % enhancement in transverse fiber bundle test (TFBT) strength in comparison with desized HMCF composites. This work provides a new strategy for preparing carbon fiber reinforced polymer composites with excellent interfacial properties.