EFFECT OF TEMPERATURE ON THE MECHANICAL-PROPERTIES OF CASEIN-G POLY(ACRYLONITRILE) FILMS

Casein was grafted with acrylonitrile in a water medium using potassium persulphate, at 60-degrees-C. The reaction mixture of acrylonitrile grafted casein was converted into films by drying the reaction mixture over a mercury surface at room temperature. Stress-strain characteristics of these films were studied at different temperatures. Stress relaxation and mechanical hysteresis were also studied as a function of temperature. The results obtained from the above experiments show that the properties of the films change above 60-degrees-C. These results suggest that the changes in the films change above 60-degrees-C. These results suggest that the changes in the films take place due to the effect produced by polyacrylonitrile [T(g) of poly(acrylonitrile) (PAN) is 80-degrees-C] chains present in the composite. The morphological studies of the fractured samples suggest that at 40-degrees-C, failure takes place in the films by crazing and shear yielding mechanisms and the material is multiphasic in nature.