Pultruded carbon fibre reinforced polymer strips produced with a novel bio-based thermoset polyester for structural strengthening

This paper presents the development and industrial manufacturing of a pultruded high-performance carbon fibre (CF) reinforced polymer (CFRP) composite strip using a bio-based unsaturated polyester (UP) resin containing more than 50% of its weight derived from renewable raw materials. The bio-based CF/UP strengthening strip, comprising unidirectional CF strands, was successfully produced and its mechanical and thermomechanical behaviours were assessed, and compared to an equivalent carbon fibre reinforced epoxy-vinyl ester (CF/VE) strip produced with conventional petroleum-based high-performance epoxy-vinyl ester resin and the same fibre ar-chitecture. The bio-based CF/UP composite strip presented 2095 MPa, 167 GPa, and 1.4% of tensile strength, modulus of elasticity, and strain at failure, respectively. These figures met or exceeded the mechanical properties of its equivalent conventional CF/VE counterpart tested under the same conditions. Furthermore, the bio-based CF/UP composite strip presented a glass transition temperature of 78 degrees C (defined from the onset of the storage modulus decay), enabling a maximum service temperature of similar to 60 degrees C, which will not likely be exceeded in most climates, highlighting its potential for structural strengthening applications, and offering a key advantage in terms of sustainability.