Effect of ethylene vinyl acetate on physico-mechanical and thermal properties of polypropylene and starch biocomposites

Abstract

The aim of this research is to investigate the effects of ethylene vinyl acetate (EVA) as compatibilizer on physico-mechanical and thermal properties of polypropylene (PP)/starch composites. PP/starch composites were prepared by the extrusion of PP resin with potato starch in co-rotating twin-screw extruder by varying starch content from 5 to 20%, where the EVA content was 10 wt% based upon potato starch. It was found that with the increase in starch content from 0 to 20% in the PP matrix, the tensile elongation increased from 19.77 to 32.0%, moisture content increased from 0.013 to 0.062%, water absorption increased from 0.035 to 0.181% and density increased from 0.912 to 0.985 g/cm3, however, the tensile, flexural and impact properties, Rockwell hardness, melt flow index and vicat softening point were found to decrease linearly. Similarly, the incorporation of starch with EVA has reduced the melting temperature of PP matrix from 162.3 to 158.55°C, the heat of fusion (▵ Hf) of PP matrix decreased from 66.52 to 27.05 J/g and so is the percentage crystallization, decreased from 31.83 to 21.45% with increase in starch content from 0 to 20 wt% in the PP matrix.