Abstract: By mixing castor oil (CO) with toluene diisocyanate (TDI) in linseed oil (LO) as dispersion medium, a composite coating of polyurethane (PU)/LO was prepared when cobalt naphthenate was used as drier.The solidified film was measured by IR,DSC and TEM.Results indicated that LO domains were dispersed in the continuous PU phase.The dispersion was then modified with cashew nut shell liquid (CNSL) containing hydroxyl groups.T_gs of both phases were increased after adding CNSL,and hardness of the paint film was enhanced.Furthermore,the dispersion was modified with coupling agent to improve adhesion property.

Key words: cashew nut shell liquid, linseed oil, castor oil, polyurethane, coatings