‘Greening’ of unsaturated polyester resin based bulk molding compound with acrylated epoxidized soybean and linseed oils: effect of urethane hybridization

Acrylated epoxidized soybean and linseed oils of different characteristics were incorporated in the absence and presence of PMDI in UP resin-based BMC up to 15 wt%. The thermal, thermomechanical, static fracture mechanical, dynamic impact, and thermal degradation properties of the modified and reference BMCs were determined. With increasing amount of functionalized plant oils, the glass transition temperature of the matrix, the stiffness (E-modulus), and Charpy impact strength of the composites decreased. On the other hand, the static fracture mechanical parameters and thermal degradation were less affected by oil modification. Type and characteristics of the plant oils affected mostly the Charpy impact strength. Additional cross-linking, induced by PMDI, resulted in some compensation of the property deterioration except the glassy modulus. The large drop in the modulus was traced to unfavored PMDI/kaolin interactions triggered by the water content of the latter. Incorporation of PMDI was associated with a prominent increase in the glass transition temperature. The results suggest that dilution of traditional UP-based BMC with acrylated epoxidized plant oils, being associated with some property degradation, is limited.