Pultruded Hybrid Fibre (Glass/Carbon) Reinforced Unsaturated Polyester Composites: Mechanical and Thermal Properties

A feasibility study on the pultrusion of hybrid fibre (glass/carbon) reinforced unsaturated polyester composites has been conducted using a proprietary method. This was in order to obtain the best mechanical and thermal properties and the optimum price composites for pultrusion. The static mechanical properties (flexural strength, flexural modulus and notched Izod impact strength), dynamic mechanical properties (dynamic storage modulus, E' and dynamic loss tangent, tanδ) and thermal properties (weight loss by thermogravimetric analysis, TGA) of pultruded hybrid fibre reinforced unsaturated polyester composites were investigated because they are of great interest and importance in structural applications, and very sensitive to the processing conditions. Results show that the flexural modulus increased with increasing carbon fibre content. The flexural strength and notched Izod impact strength increased with decreasing carbon fibre content. The E' increased with increasing carbon fibre content, calcium carbonate content and postcure temperatures. The peak in the loss tangent was shifted to a higher temperature when the carbon fibre content was increased. From TGA, the weight loss of the pultruded composites increased with decreasing carbon fibre content in an inert (N ₂ gas) atmosphere. Furthermore, they increased with increasing carbon fibre content in an air atmosphere.