Author : Srabayeeta Basu Roy, Subhas C Shit, Ranjan A Sengupta and Premal R Shukla

In this study to determine the possibility of using starch as biodegradable filler in the thermoplastic polymer matrix, starch-filled polypropylene (PP) composites are prepared by extrusion of PP resin with 5, 10, 15, and 20 wt % of potato starch in corotating twin-screw extruder. The injection molded test specimens are tested for physicomechanical properties such as tensile and flexural properties, Izod impact strength, density, moisture and water absorption. Characterization of the thermal properties by melt flow index (MFI), vicat softening point (VSP), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques has also been done. The results show that, with increase in starch content, tensile modulus, flexural strength, flexural modulus, moisture absorption, water absorption and density of the PP composites increased but, tensile strength and elongation, impact strength, hardness and MFI of the PP composites decreased while retaining the VSP. For the biodegradability test. Poly propylene (PP)/potato starch (PS) blend films are prepared using the two roll mill machine. The films are investigated by soil burial method over a period of 4 months. The percentage weight loss of the bio-composites in the compost soil burial test is increasing with increasing PS content. The biodegradability of the bio-composites is enhanced with increasing starch content because the PS is easily attacked by microorganisms. Any changes in the various properties of the PP/PS before and after degradation are monitored using FTIR spectroscopy, a scanning electron microscope (SEM) for surface morphology, a thermo gravimetric analyzer (TGA) for rapid determination of starch content and a differential scanning calorimeter (DSC) for crystallanity. It can be concluded from the results that use of these bio-composites will reduce the environmental problems associated with waste pollution and the study findings support the predicted application of bio-composites as green-composites or eco-materials.

Keywords: Polypropylene Potato Starch Bio-composite, Mechanical properties, Thermal properties, Morphology, Soil burial test

Article published in International Journal of Current Engineering and Technology, Vol.5, No.2 (April-2015)