Co-authors​ :

 Manato KUMADA (JAPAN), Ryo HIGUCHI (JAPAN), Tomohiro YOKOZEKI (JAPAN), Takaya SUZUKI (JAPAN) 

Resins which are used for matrix of Carbon Fiber Reinforced Plastics (CFRPs) are broadly divided into two groups, thermoplastic resins and thermosetting resins. The latter are mainly used in industrial applications for their superior mechanical properties and higher resistance to heat and chemicals derived from their cross-linked networks. However, they have some disadvantages of low reprocessibility, for which they are disposed of by incineration and landfilling, leading to environmental pollution. In 2011, Leibler and co-workers published a paper on a new type of resin, Vitrimer. It has reversible bonds in its cross-linked network and shows superior mechanical properties like thermosettings at working temperature and reprocessibility like thermoplastic when heated. Vitrimer shows characteristic behavior at specific temperature called topology freezing transition temperature (Tv). Above this temperature, bond exchange reaction of reversible bonds become active and topology rearrangement of cross-linked network occurs, which enables self-healing of resin damage. For these properties, vitrimer is expected as another option for matrix of CFRP from the perspective of environmental issues.

In previous studies, various kinds of vitrimer and carbon fiber reinforced vitrimer (vCFRP) with different mechanisms of bond exchange reaction are dealt with. However, most of these studies focused on self-healing property in microscale and mainly discussed material recycling methods such as remolding after grinding vitirmer or vCFRP into powder and retrieving fiber and resin respectively by dissolution. In other words, self-healing property of vitrimer and vCFRP in mesoscale is not evaluated enough. Therefore, considering application for structural members, it is important to investigate behavior of vCFRP laminates in mesoscale.

This study aims to reveal mechanical, thermal, and self-healing properties of vitrimer and vCFRP. Especially, we deal with epoxy-based vitrimer which has disulfide bonds as reversible bonds and carbon fiber composite of it. Firstly, we conduct tensile test and bending test to achieve mechanical properties of them and compare with those of a basic epoxy resin and its composite. Secondly, we conduct differential scanning calorimetry (DSC) to achieve their thermal properties. Then, we observe self-healing behavior in thermostatic chamber by heating above Tv. Finally, we will evaluate mechanical, thermal, and self-healing properties obtained from experiments based on continuum damage mechanics.