Resorcinol‐Derived Vitrimers and Their Flax Fiber‐Reinforced Composites Based on Fast Siloxane Exchange

Abstract

AbstractNatural fiber‐reinforced composites are gaining increased interest for their significantly reduced carbon footprint compared to conventional glass or carbon fiber‐based counterparts. In this study, natural fibers are used in a resorcinol‐based epoxy resin that is thermally reshapable at higher temperatures (>180 °C) by using fast exchanging siloxane bonds, catalyzed by 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene. Stress relaxation times of only about 6 s at 220 °C can be reached. A resorcinol‐based epoxy compound is selected because it can be derived from cellulose, opening ways for more sustainable and reshapable composite materials. In a last step of the research, the low viscosity vitrimer formulation (<200 mPa s) is applied to make a flax fiber‐reinforced composite using an industrially relevant vacuum‐assisted resin infusion process. A section of this composite is successfully reshaped, which allows for envisioning a second life for natural fiber‐reinforced composites.