Surface Degradation Assisted Welding for Vitrimer Composites

Composites employing vitrimer (referred to as dynamic covalent network polymer) matrix can be directly welded thanks to bond re-association. Strong welding of vitrimer composite is anticipated to fabricate complex com-posite structures but remains challenging. Here, surface degradation is introduced to assist in welding carbon -fabric-reinforced epoxy vitrimer composites. The composites are immersed in ethylene glycol for a controlled degradation time before welding. We call it controlled surface degradation. The chemical and physical properties of the degraded surface are measured to reveal the effects of degradation on welding. The welding strengths with various welding pressure and time are studied by single lap-shear tests. Comparing with previously direct welding, the presented surface degradation assisted welding highly increases the welding strength, while significantly lowers the welding pressure.