Characterization of Castor Oil and Diphenyl Methane Diisocyanate-based Polyurethane-Polystyrene Interpenetrating Networks

Abstract

Castor oil is an abundant natural polyol. It has been subjected to extensive investigations for polyurethane formation, suitable for a variety of applications. In this work, polyurethane prepolymers have been synthesized by bulk polycondensation of the moisture-free castor oil with diphenyl methane diisocyanate at room temperature. These prepolymers have been then cross-linked in situ with different quantities of styrene to prepare simultaneous interpenetrating polymer networks (IPNs). The composition of the polyurethane and polystyrene IPNs ranges from 10 to 50% by weight. The morphology, mechanical properties, chemical absorption, and swelling behavior of the IPNs prepared have been analyzed to evaluate the effect of styrene content in the IPNs. The tensile modulus improves with increasing quantity of styrene with a maximum at 50%. The absorption of these IPNs is maximum in pyridine and decreases with increasing quantity of styrene up to 40% and a sudden jump has been observed for 50% styrene content. For swelling study, the diffusivity coefficient increases with increasing PS content while sorption coefficient shows a decreasing trend.