Preparation and Characterization of Recyclable Basalt Fiber Composites

Abstract

Although epoxy (EP) based composites possess excellent mechanical properties, their highly cross‐linked network structure makes it difficult to recycle once discarded, resulting in significant waste of resources, and an environmental burden. In this study, biobased tannic acid was used as the raw material to synthesize carboxylate tannic acid (TACOOH) via carboxylation modification, which was then combined with methyl hexahydro phthalic anhydride (MeHHPA) to construct a biodegradable epoxy curing system rich in ester bonds. Concurrently, basalt fibers (BF) were surface‐modified using the silane coupling agent KH560 to prepare TACOOH/EP/BF composites. The mechanical properties, thermal stability, and feasibility of fiber recovery and reuse of the composites were investigated. The results indicate that modification with KH560 enhanced the interfacial bond strength between the fibers and the resin matrix; the flexural strength of the modified composite (MBF/EP@TACOOH) reached 254.30 MPa, representing a 12.15% increase compared to the unmodified system; following degradation and recovery in a 180°C ethylene glycol/water mixture, the flexural strength of the composite fabricated from the recovered fibers (RBF) still reached 248.40 MPa, with a retention rate of 97.7%, and its thermal decomposition behavior was consistent with that of the virgin fiber system. Scanning electron microscopy and monofilament tensile tests indicated that the recovery process caused only minor damage to the fiber's internal structure, and the silane active sites remaining on the surface were still able to effectively ensure interfacial performance. This study provides a green and feasible technical pathway for the high‐value recovery of epoxy composites and the recycling of fibers.