A new series of interpenetrating polymer network based on castor oil

toluene diisocyanate and hydroxyethyl methacrylate (HEMA) (Network I) and castor oil

TDI and polypropylene glycol (PPG) (Network II) was prepared. Their structure and properties were studied by solid NMR and dynamic mechanical analysis. Mechanical and dynamic mechanical measurements show that the tensile properties increase and tan 6 peaks broaden. Solid NMR results indicate that the interface ratio increase but it does not vary with relative amount of network I and net-work II whtch reveals that the samples might exhibit a core-shell structure.