The castor oil was converted into maleic acid ester (i.e. maleated castor oil

MACO) by the reaction with maleic anhydride. Afterwards

the resultant MACO was free-radically copolymerized with reactive diluents (styrene

St) and cured to form foam plastics through conventional foaming technique. By changing MACO/St ratio

mechanical properties and aerobic biodegradability of MACO foams can be easily adjusted. To understand the biodegradation mechanism of the castor oil based plastic foam

various characterization techniques were employed in a systematic way. Compost tests in laboratory soil combined with molecular characterizations demonstrated that the bio-foam has acquired excellent biodegradability. Destruction of the network structure of the castor oil based polymer resulted from fission of ester groups due to attack of microorganisms. The final product of compost tests proved to be carbon dioxide. Inoculation of fungi on the castor oil based polymer further revealed that the vegetable oil acted as carbon source of growth of aspergillus niger. Under the catalysis of lipase

castor oil

MACO and its foam were hydrolyzed to produce fatty acids. The results of different degradation tests matched each other

which not only confirmed biodegradability of MACO plastics

but also preliminarily revealed molecular mechanism of the biodegradation process.