High-performance thermosets with tailored properties derived from multi-arm stared vanillin and carbon fiber composites

Vanillin, a rigid compound can be separated from lignin, is a promising sustainable candidate for industrial and high performance polymers, while synthesis of hexa-epoxies is challenging. Meanwhile, carbon fiber reinforced bio-based polymers combining high performance are more difficult to be achieved because of the contradictions of liquidity and high rigidity in the polymer structure and performance. In this paper, a novel hexa-epoxy functionalized bio-based epoxy resin (HPVIGEP) with a multi-arm star structure, which simultaneously reduced the viscosity and improved thermo-mechanical properties. The rheological behavior analysis results of HPVIGEP indicated that the viscosity was 3406.9 mPa·s at 25°C, which dramatically decreased by 75.8% compared to DGEBA (14,096 mPa·s), leading to excellent processability and adaptability. At the same time, the study on mechanical properties revealed that the cured HPVIGEP manifested 30.6%, 33.7% and 49.0% in higher tensile strength, tensile modulus and storage modulus (30°C) than of cured commercial epoxy, respectively. The tensile strength and flexural strength of carbon fiber composites which were applied HPVIGEP were increased by 9.3% and 10.9%, respectively. In a word, this work provides the promise for the application of environmentally friendly bio-based composite materials.