Effect of temperature on the mechanical properties of casein-g-poly(acrylonitrile) films

✍ Scribed by N. Somanathan; R. Sanjeevi

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 612 KB
• Volume: 30
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(94)90273-9

✦ Synopsis

Casein was grafted with acrylonitrile in a water medium using potassium persulphate, at 60°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°C. These results suggest that the changes in the films take place due to the effect produced by polyacrylonitrile [Tg of poly(acrylonitrile) (PAN) is 80°C] chains present in the composite. The morphological studies of the fractured samples suggest that at 40°C, failure takes place in the films by crazing and shear yielding mechanisms and the material is multiphasic in nature.