Effect of hybrid phenolic hollow microsphere and silica-filled vinyl ester composites

Abstract

Study on phenolic hollow microspheres (PHMS)-filled vinyl ester (VE) composites has been carried out. Effect of adding PHMS fillers at different filler loading on flexural, impact, and thermal properties were studied. The impact strength increased with the addition of PHMS fillers but at the expense of flexural strength, flexural modulus, and thermal stability of the composites. The second stage of this article aims to study the effect of adding silica as second filler in PHMS-filled VE composite system, and the influence of silane treatment on the mechanical properties of silica/PHMS/VE hybrid composites. PHMS/VE composites filled with silane-treated silica were found to show an increase in flexural modulus with increasing filler content. On contrary, the untreated silica fillers were observed to provide reinforcing effect in PHMS/VE composites at rather low filler concentration. The flexural strengths of silica/PHMS/VE hybrid composites were found to decrease with addition of silica content in the composites, and further decreased with increasing in silica content for both untreated and treated silica/PHMS-filled VE composites. Addition of silane-treated silica in the composites also provided an increase in the impact resistance of the PHMS/VE composites. Interestingly, the addition of silica and PHMS fillers in VE matrix has resulting in low density composites with improved flexural modulus and impact resistance.