Starch-based biodegradable film with poly(butylene adipate-co-terephthalate): preparation, morphology, thermal and biodegradation properties

Starch was extracted from potato (Solanum tuberosum) cultivated in Nepal. The yield of starch of different sorts of the species S. tuberosum was compared with each other. Extracted starch (E St.) Kufre Sindure was characterized and compared with commercial starch (Com St.) by the Fourier transform infrared spectroscopy (FTIR). The properties of extracted starch were evaluated by measuring ash content, moisture content and amylose content. A series of butylene adipate-co-terephthalate (PBAT)/TPS blend of varying concentration (5%, 10%, 20% and 30%) were prepared using citric acid (compatibilizer) and glycerol as plasticizer, respectively, via solution casting method. The physical and chemical properties of resulting blends were characterized by FTIR and X-ray photoelectron spectroscopy (XPS). The FTIR results proved the esterification reaction between PBAT, thermoplastic starch (TPS) and citric acid in blends. Morphology of the PBAT/TPS film was studied through scanning electron microscopy (SEM) and XPS analysis. Microindentation measurements revealed improvement in mechanical properties of PBAT with the loading of starch. Thermogravimetric analysis (TGA) showed decrease in the thermal stability of PBAT/TPS blend. Degradation behavior of blend showed that rate of degradation was increased with increase of starch content.