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

The composites of polybenzoxazine (PBZ) containing functionalized plasma treatment basalt fibers (fP‐BFs) were fabricated through in‐situ polymerization‐mixing technique. fP‐BFs is an effective reinforcement material that can improve the mechanical, thermal, and interfacial properties of composites. Surface activation of fP‐BFs can be enhanced through plasma modification, which improves the interaction between fP‐BFs and 3‐aminopropyltriethoxysilane. A systematic study on fP‐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 fP‐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 fP‐BFs improved the Tg of the composites. Among them, fP‐BFs‐5/PBZ showed the highest Tg, reaching 233.2 °C. Highlights Plasma treatment produced multi‐level structure of basalt fibers (fP‐BFs). Polybenzoxazine (PBZ)/fP‐BFs composites showed excellent performance. Interfacial bonding mechanism between fP‐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. PBZ composites with excellent comprehensive performance strengthed by basalt fibers based on multi‐level interface structure design strategies.