DEVELOPMENT AND CHARACTERIZATION OF VINYL ESTER OLIGOMER (VEO) MODIFIED UNSATURATED POLYESTER INTERCROSSLINKED MATRICES AND COMPOSITES

An intercrosslinked network of varying percentage of vinyl ester oligomer (VEO) modified unsaturated polyester matrices has been developed. Vinyl ester oligomer was prepared by reacting commercially available epoxy resins GY 250 (Ciba-Geigy) and acrylic acid and was used as toughening agent for unsaturated polyester (UP) resin. Unsaturated polyesters modified with 10%, 20% and 30% (by wt) of vinyl ester oligomer were made. E-glass reinforced composites were fabricated by hand lay–up technique using VEO-UP matrix systems. VEO modified unsaturated polyesters were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and heat deflection temperature (HDT) analysis. The matrices in the form of castings and E-glass reinforced composites were characterized for their mechanical properties, i.e., tensile strength, flexural strength and unnotched-Izod impact test as per ASTM methods. Data obtained from mechanical studies and thermal characterization indicate that the introduction of VEO into unsaturated polyester resin improves the thermo-mechanical properties and negatively affects the moisture resistance according to its percentage concentration.