In-situ polymerizable thermoplastic and bio-epoxy based composites for offshore renewable energy applications

This study evaluates various quasi-static mechanical properties of an in-situ polymerizable thermoplastic and a bio-based thermosetting composite comprising of non-crimp fabric reinforcement for potential use in the next generation of Offshore Wind and Tidal Power platforms. Mechanical properties are characterized under tensile, flexural, in-plane shear and interlaminar shear loading. Results reveal that the evaluated properties differ based upon matrix type. Fractographic evidence from scanning electron microscopy is used to explain the differences observed and was generally consistent in terms of revealing cohesive failure at the fiber-matrix interface for the thermoplastic composite and contrasting adhesive failure for the thermosetting composite. For glass fiber reinforcement, the thermoplastic composite is superior in terms of flexural 90° properties (+20%) while the thermosetting composite performed better in flexure 0° in terms of both strength (+15%) and modulus (+25%). In terms of interlaminar shear, the thermosetting composite exhibited higher strength (+14%) while Tensile and in-plane shear properties are similar for composites of both resin systems. Overall, neither composite is superior in terms of overall mechanical properties and both matrices show promise as a stepping stone towards the use of more sustainable constituents in offshore structures. Highlights: Quasi-static mechanical performance and failure analysis of relatively sustainable composites are presented. Failure analysis indicate cohesive failure of the thermoplastic based composite and interfacial failure of the thermosetting based composite. Proposed composites are benchmarked against the composites manufactured using conventional resins. Overall, both matrices show promise as a stepping stone towards more sustainable offshore structures.