Resveratrol-based benzoxazine monomers containing furan and thiophene functionalities (RFuBZ and RThBZ) were synthesized via Mannich condensation using benzaldehyde as the aldehyde source. Structural characterization by FT-IR and NMR spectroscopy confirmed the successful formation of the targeted benzoxazine monomers. Thermal polymerization followed by carbonization and KOH activation produced heteroatom-enriched porous carbons with retained N-, O-, and S-containing functionalities. Raman, XPS, and nitrogen sorption analyses revealed that the heterocyclic structure significantly affected heteroatom retention and pore development. Although poly(RFuBZ)-800 exhibited a higher BET surface area (194 m2 g−1) than poly(RThBZ)-800 (52 m2 g−1), poly(RThBZ)-800 demonstrated superior electrochemical performance, delivering a specific capacitance of 195 F g−1 at 0.5 A g−1 and retaining 95.11% of its capacitance after prolonged cycling. The enhanced performance is attributed to heteroatom-induced pseudocapacitance and improved charge-transfer characteristics. These results highlight the importance of heteroatom engineering over surface-area enhancement alone for developing high-performance benzoxazine-derived porous carbon electrodes for supercapacitor applications.
Poly(vinylbenzyl chloride) (PVBC) structures are often prepared by crosslinking benzyl chloride functionalities with nitrogen-containing crosslinkers, a process that is undesirable in applications sensitive to heteroatom content. Consequently, developing nitrogen-free PVBC structures that retain benzyl chloride reactivity remains an important challenge. Here, we report a nitrogen-free approach for preparing crosslinked PVBC fibers through complementary polymer modification and thermal curing. PVBC was independently functionalized with epoxy and anhydride groups via atom transfer radical addition-mediated grafting of epoxy-containing groups and Friedel-Crafts modification with methyl-5-norbornene-2,3-dicarboxylic anhydride. Mixtures of the complementary polymers were drawn into fibers and thermally cured to promote crosslinking, with ATR-FTIR spectroscopy and combustion elemental analysis providing complementary qualitative and quantitative evidence of successful polymer modification and compositional changes before and after curing. The resulting fibers were insoluble in chloroform while retaining approximately 83% of the original benzyl chloride groups after crosslinking. Subsequent reaction with trialkyl phosphites demonstrated the retained chemical reactivity of the crosslinked fibers, with trimethyl phosphite treatment yielding an apparent degree of functionalization of 19.0% based on elemental chlorine analysis. Direct elemental phosphorus analysis of fibers modified with triethyl phosphite confirmed successful phosphonate incorporation. Nitrogen was not detected in the analyzed phosphonated fibers. This approach provides a nitrogen-free route to crosslinked PVBC fibers that retain substantial chemical reactivity for subsequent functionalization, making it attractive for separations, sensing, and heteroatom-sensitive analytical applications.
In this study, a furan-based epoxy resin (EP-FA) was synthesized through an epoxide ring-opening reaction, and subsequently cross-linked with a curing agent (MD230) containing maleimide-functionalized groups through thermally reversible Diels-Alder (DA) chemistry. The structures of MD230 and the resulting epoxy resin were characterized using 1HNMR and FTIR spectroscopy. Then epoxy resins with different contents of curing agent were prepared, and their properties were also characterized. The nanoindentation and scratch test results indicated that the EP-FA-MD230-1 formulation had the highest hardness (H) and excellent adhesion strength. The tribological performance evaluation indicated that the coating also possessed the best tribological properties. The thermal healing procedure of damaged coating was conducted at 180 °C for 20min, and the healed coating showed higher impedance modulus than the original sample. After immersion in 5 wt% NaCl solution for 21 days, the impedance modulus of healed EP-FA-MD230-1 coating still remained at 8.63 × 1010 Ω cm2. Meanwhile, the recycled sample could recover 90% of its original tensile strength by a thermal solvent recycling method. This work provides a method for the preparation of Diels-Alder epoxy as protective coatings that combine corrosion resistance, self-healing and recyclability in the field of metal materials.
