POLYMERS FROM RENEWABLE RESOURCES .9. INTERPENETRATING POLYMER NETWORKS BASED ON CASTOR-OIL POLYURETHANE POLY(HYDROXYETHYL METHACRYLATE) - SYNTHESIS, CHEMICAL, THERMAL, AND MECHANICAL-PROPERTIES

A number of polyurethanes were synthesized by reacting castor oil with hexamethylene diisocyanate, varying the NCO/OH ratio. The polyurethan es were reacted with 2-hydroxyethyl methacrylate (HEMA) to prepare the interpenetrating polymer networks (IPNs) using benzoyl peroxide as th e initiator and ethylene glycol dimethacrylate (EGDM) as the crosslink er. The IPNs are partly soluble in some of the solvents and are less r esistant to alkali, but more resistant to acid. The solvent absorption is more pronounced in benzene than in toluene. A novel computerized L OTUS package was used to calculate the kinetic parameters. All the IPN s decomposed with 2-4% weight in the temperature range of 0 to 200 deg rees C; 10% weight loss occurs at 300 degrees C and 40% weight loss oc curs at 400 degrees C. There is a rapid weight loss from 10 to 90% in the temperature range of 400-500 degrees C. From the kinetic data, it is clear that the degradation process of the IPNs is slower in the tem perature range 300-400 degrees C and faster in the temperature range o f 440-560 degrees C. (C) 1997 John Wiley & Sons, Inc.