【Frontiers in HaiChuan Chemical Technology】Another technological breakthrough in high-end carbon fiber composite materials CFRP

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Recently, the R&D team at Beijing Zhongke Lixin Technology Co., Ltd. has creatively enhanced the impact resistance of carbon fiber reinforced polymer (CFRP) materials by employing an epoxy resin toughening strategy based on B-O dynamic covalent bonds, achieving a technological breakthrough in the field of high-end carbon fiber composites. This achievement helps to reshape the structure of China’s carbon fiber industry, providing core material support for the upgrading of modern high-end manufacturing sectors. CFRP is a fiber composite material formed by combining carbon fibers with resin, and it is used to manufacture key structural components in aircraft and automobiles due to its excellent specific strength, specific stiffness, and corrosion resistance. High-performance carbon fiber composites are the foundation for developing advanced unmanned aerial vehicles and sophisticated new energy vehicles. Although CFRP materials possess excellent static strength and stiffness, under low-speed impacts, they are highly prone to brittle failures such as delamination and matrix fragmentation, resulting in a sharp decline in their structural load-bearing capacity. The insufficient impact resistance of CFRP has become a key issue limiting its application. The poor toughness of CFRP stems, on the one hand, from the low fracture toughness of the thermosetting resin matrix, and on the other hand, from the weak interfacial adhesion between the resin and the carbon fibers. To improve the impact resistance of CFRP, the research team at Zhongke Lixin proposed an epoxy resin toughening strategy based on B-O dynamic covalent bonds. Boric acid is incorporated into the epoxy resin matrix using a nano-silica particle/polyethylene glycol suspension (STF) as a dispersant, and then a new type of epoxy resin system (FEP) with B-O\B-N dynamic linkage bonds is formed within the epoxy resin matrix through a thermal curing process. At the same time, during the preparation of CFRP, functional groups such as hydroxyl and amino groups on the surface of carbon fibers can also form dynamic bonds with the B atoms in the resin, thereby effectively enhancing the interfacial bonding strength. To improve the impact resistance of CFRP, the research team at Zhongke Lixin proposed an epoxy resin toughening strategy based on B-O dynamic covalent bonds. Boric acid is incorporated into the epoxy resin matrix using a nano-silica particle/polyethylene glycol suspension (STF) as a dispersant, and then a new type of epoxy resin system (FEP) with B-O\B-N dynamic linkage bonds is formed within the epoxy resin matrix through a thermal curing process. At the same time, during the preparation of CFRP, functional groups such as hydroxyl and amino groups on the surface of carbon fibers can also form dynamic bonds with the B atoms in the resin, thereby effectively enhancing the interfacial bonding strength. The research results show that, compared to conventional carbon fiber/epoxy resin composites (CF/EP), carbon fiber/epoxy resin composites (CF/FEP) exhibit a significant improvement in impact resistance. Tests using pendulum impact and post-impact compressive strength (CAI) showed that the impact fracture toughness and CAI strength of CF/FEP increased by over 70% and 35%, respectively. The relevant research findings have been published in the authoritative international journal on composites: “Composites Part B: Engineering”.