composition for preparing a biodegradable polyurethane - based foam and a biodegradable polyurethane foam , comprising mixtures based on poly polymer , polyols of renewable source , isocyanates and additives , with the object of preparing biodegradable polyurethane foams . in the process , the poly plus the polyol , the isocyanate and the additives are previously mixed in specific mixers ; once the homogenization is reached , the mixture is poured in mold for growing . after curing , the resulting product presents foam characteristics , with its density , toughness and cell size varying according to the proportion of the reagents and allowing the manufacture of several products .