Surface degradation assisted welding for vitrimer composites

• Published in: Materials letters 2022-12, Vol.328, p.133051, Article 133051
• Main Authors: An, Le, Jin, Chenyu, Li, Xiuzhao, Zhao, Wenzhe
• Format: Article
• Language: English
• Subjects: Bond re-association; Polymeric composite; Surface degradation; Vitrimer; Welding
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2022.133051

•Strong welding of vitrimer composites is anticipated but remains challenging.•Surface degradation is introduced to assist in welding epoxy vitrimer composites.•A high welding strength of ∼25 MPa is obtained.•The required pressure is two orders of magnitude smaller than that by direct welding. 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 composite 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.