High-efficiently renewable hyperbranched epoxy resin/carbon fiber composites with both long service life and high performance

Abstract

Wind turbine generators with high power will develop increasingly to achieve an ambitious goal of carbon peaking and carbon neutrality, demanding urgently larger and lighter blades with long service life and high mechanical strength. Here we fabricate renewable composites with thiol-functionalized carbon fibers (TCF) and epoxy-ended hyperbranched polymers (HT12), exhibiting a competitive property. Compared with the corresponding performance of diglycidyl ether of bisphenol A (DGEBA)/pristine carbon fibers composites, the tensile strength, tensile modulus, flexural strength, flexural modulus, and interlaminar shear strength of HT12/TCF composites are increased by 89.84%, 154.55%, 217.89%, 366.62%, and 376.52%, respectively. The service life of the HT12/TCF composites is about 200 years at 40 °C by simulating environmental experiments of acid rain and seawater resistance, being much longer than DGEBA/carbon fibers of about 20 years. Additionally, the HT12/TCF composites can be rapidly decomposed into oligomers and carbon fibers under mild conditions, which can be reused to prepare HT12/TCF composites by reacting directly with formaldehyde via a condensation between the amino group and the aldehyde group. After recycling twice, the composites still maintain high mechanical strength, suggesting highly efficient renewability of carbon fibers and epoxy resins. This research provides a sustainable approach for preparing high-performance environmentally-friendly epoxy resin/carbon fiber composites capable of uprecycling, and well-balancing service life and performance.