Polymers from Renewable Resources. IV. 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 polyurethanes were reacted with such acrylic monomers as acrylamide and methacrylamide 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 durability, solvent absorption, outdoor weathering, and aging properties of IPNs have been studied. Thermogravimetric analysis was used to study the thermal behavior of IPNs and the evaluation of kinetic parameters. A number of equations, such as those of Freeman-Anderson, Broido, Piloyan-Novikova, Horowitz-Mitzger, and Coats-Redfern, have been used to determine the kinetic parameters. The degradation mechanism is discussed.