Blends based on LDPE and chitin or chitosan were prepared under high-temperature shear deformations in a rotor disperser at different initial ratios of the components. Although one of the components is an infusible polymer (polysaccharide), the powder blends were obtained. The composition of the powder fractions was shown to be identical to the original blend composition. It was found that the addition of poly(ethylene oxide) to the mentioned blends improves the biodegradability of the polymer materials and extends their application areas. Using various physicochemical methods, the structural and morphological changes in the polymer compositions under the action of shear deformations were examined, the mechanical characteristics of prepared films were determined, and also the features of their bio-, thermo-, and photo-oxidative degradation were studied. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 1850-1859, 2011