Cationic water-borne polyurethanes (CWPU) were prepared and blended with wheat gluten (WG) in aqueous dispersion. The freeze-dried blend powders of WG/CWPU were thermally compression-molded into sheets. The tensile strength of the WG/CWPU blends decreased with increasing CWPU content, showing a relationship between the composition of the sheets and their mechanical properties. FTIR spectra reveal that the free carbonyl in the blend results in a decrease in the hydrogen-bonding interaction of the WG. SEM images show that the morphology of the cross-sections of the blends is homogenous. The dynamic thermal behavior of the blends illustrates that the WG is plasticized by CWPU, with the result that the relaxation transition of the WG becomes broader and the temperature transition of WG changes slightly. The water resistance of the WG was also improved by blending it with the CWPU. Biodegradation of the blends in soil resulted in a loss in mass of the samples of more than 60% w/w after burial for 15 days. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Glycerol-plasticized wheat gluten was prepared by mixing in an internal mixer equipped with sigma rotors, and then thermally compression-molded to form a sheet for crosslinking and tensile tests. Referring to rubber vulcanization process, rotorless curemeter was applied to test the vulcanization characteristic parameters of the molded round samples, which could be used to calculate the activation energy and reaction rate of crosslinking occurring in wheat gluten when heated. Vulcanizing curves obtained show that the optimum temperature for processing glycerol-plasticized wheat gluten is 150°C, and that activation energy and reaction rate of crosslinking in wheat gluten plasticized with 20 wt % glycerol reach minimum and maximum values, respectively. In addition, glycerol content, plasticizing time, and temperature have significant effects on the mechanical properties of thermomolded wheat gluten plastics. The factors are closely related to the establishment of a covalent network resulting from the formation and rearrangement of disulfide bridges in wheat gluten. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011