Thermal Expansion Coefficient: a macro-scale indicator of particle filtration in composites fabricated by resin infusion

Abstract The particle loaded composites are being used widely for tailor-made properties, however, the particles tend to create concentration gradient along part length during infusion. Keeping in view the limitations of existing characterization approaches, thermal expansion coefficient (CTE) is used as a macroscopic tool to measure particle filtration for the first time. Composite plates were fabricated by VIM (Vacuum Infusion Moulding) process from glass woven fabric and vinyl ester resin containing silica microparticles (0, 0.5, 1.0, 1.5, and 2.0%). CTE was determined from different positions from composite samples. It was found that the CTE was low at the inlet indicating a high particle concentration. A gradual decrease in the particle concentration was observed from the inlet towards the outlet. The variation of CTE due to the gradient of particle concentration was validated using COMSOL Multiphysics®. The results show that both the experimental and numerical values are in agreement.