Interpenetrating polymer networks from castor oil‐based polyurethanes and polystyrene, XXV

Abstract

Interpenetrating polymer networks (IPNs) of castor oil-based polyurethanes and polystyrene were prepared by simultaneous polymerization. The liquid prepolyurethanes were formed by reacting the hydroxyl functionality of castor oil with isophorone diisocyanate using different stoichiometric NCO/OH ratios. These prepolyurethanes were mixed with styrene monomer and subsequently polymerized by free radical polymerization initiated by benzoyl peroxide in the presence of the crosslinker 1,4-divinyl benzene. The interpenetrating polymer networks. PU/PS IPNs, were obtained as tough and transparent films by the transfer moulding technique. These IPNs were characterized by the static mechanical properties (tensile strength, Young's modulus and % elongation), thermal properties and morphology. The dielectric relaxation properties (a, E', E" and tan 6) of the IPNs at different temperatures were studied.