Effect of Starch Content on the Physico- Mechanical Properties of Recycled Polypropylene/Sweet potato Thermoplastic Starch Blend

Abstract

(RPPB)/ thermoplastic sweet potatoes starch (TSPPS) with compatibiliser (polypropylene –grafted-maleic anhydride) was prepared by melt blending on the two roll mill, and effect of the thermoplastic starch loading of 0,10,20,30,40 and 50wt% (sample A-F) on the physical and mechanical properties of the blend has been reported. Starch from sweet potato peel was treated with 0.16% aqueous solution of sodium hydrogen sulphite as a preservative. pH, Ash content, moisture content and FTIR were used to characterise the produced sweet potatoes peel starch. Hardness, tensile strength and percentage elongation at break properties decrease as the thermoplastic starch content increases from 0-50wt. %. The impact strength was found to be improved at sample C (20wt%) as thermoplastic starch content increases when compared to the control sample (sample A) while the modulus of elasticity, density and water absorption results shows that there was an increase in these properties as thermoplastic starch content increases. Biodegradation result of the blend upon soil burial for 98 days shows that the higher the starch content in the blend, the faster the rate of degradation.