POLYMERS FROM RENEWABLE RESOURCES .4. CASTOR-OIL-BASED INTERPENETRATING POLYMER NETWORKS DERIVED FROM ISOPHORONE DIISOCYANATE POLY(ACRYLAMIDE) AND POLY(METHACRYLAMIDE)

A number of polyurethanes were synthesized by reacting castor oil with isophorone diisocyanate while varying the NCO/OH ratio. All these pol yurethanes were reacted with such acrylic monomers as acrylamide and m ethacrylamide by using ethylene glycol dimethacrylate as a crosslinker and benzoyl peroxide as the initiator. The physicochemical properties of interpenetrating polymer networks (IPNs) are reported. The durabil ity, solvent absorption, outdoor weathering, and aging properties of I PNs have been studied. Thermogravimetric analysis was used to study th e thermal behavior of IPNs and the evaluation of kinetic parameters. A number of equations, such as those of Freeman-Anderson, Broido, Piloy an-Novikova, Horowitz-Mitzger, and Coats-Redfern have been used to det ermine the kinetic parameters. The degradation mechanism is discussed.