Soy protein concentrate, a potential alternative to petrochemical polymers, was cross-linked with formaldehyde at 0.5, 1, 2.5, 5 and 7.5% (w/w). The materials were then compression-moulded into plastic tensile bars and tested for tensile and yield strength, percentage elongation and water absorption. The infrared spectra of the cross-linked product were studied. The degradation pattern of the cross-linked product was monitored by thermogravimetric analysis. A computerised LOTUS package method that we developed was used for evaluating the kinetic parameters. The biodegradability of the cross-linked product was also investigated. (c) 2005 Society of Chemical Industry.