Synergetic control of multi‐level interface structure of basalt fibers by plasma and chemical functionalization to enhance the mechanical, thermal and interfacial performances of <scp>PBZ</scp> composites

Abstract The composites of polybenzoxazine (PBZ) containing functionalized plasma treatment basalt fibers ( f P‐BFs) were fabricated through in‐situ polymerization‐mixing technique. f P‐BFs is an effective reinforcement material that can improve the mechanical, thermal, and interfacial properties of composites. Surface activation of f P‐BFs can be enhanced through plasma modification, which improves the interaction between f P‐BFs and 3 ‐aminopropyltriethoxysilane. A systematic study on f P‐BFs/PBZ composite showed that a processing power of 300 W, a processing time of 5 min, and a fiber content of 9% can achieve good comprehensive mechanical properties. Thermogravimetric analysis results showed that f P‐BFs‐7/PBZ has the highest thermal stability, and its carbon residue rate, decomposition temperature and thermal decomposition activation energy are 36.80%, 452.2 °C and 133.56 kJ/mol, respectively. The dynamic mechanical analysis experiment showed that the addition of f P‐BFs improved the T g of the composites. Among them, f P‐BFs‐5/PBZ showed the highest T g , reaching 233.2 °C. Highlights Plasma treatment produced multi‐level structure of basalt fibers ( f P‐BFs). Polybenzoxazine (PBZ)/ f P‐BFs composites showed excellent performance. Interfacial bonding mechanism between f P‐BFs and PBZ was elucidated. Interfacial interactions between BFs and PBZ contributed to property enhancement. This work provided a green fabrication strategy of PBZ composites.