Mechanical and Physical Properties of Polylactic Acid (PLA)/Thermoplastic Starch (TPS) Blends

Polylactic acid (PLA) is most known as a biodegradable plastic, often faces such a problem mainly related to flexibility. In order to improve the brittleness of PLA and to produce biodegradable plastic with good combination of cost and performance, we have focussed here on adding thermoplastic starch (TPS) within the PLA matrix. To improve the interfacial adhesion between TPS and PLA, the TPS structure was chemically modified by using citric acid (CA). The ratio between PLA/TPS was chosen at 60/40 and 40/60 and CA content was varied from 1 to 4%. The tensile strength, together with Young's modulus for (60/40) and (40/60) of the PLA/TPS blend, were found to increase after modification with CA. However, the elongation at break of PLA/TPS (60/40) blend was decreased. This result showed that higher loadings of TPS in the blend tend to elongate due to the flexibility of TPS. On the other hand, by modifying the TPS with CA, it showed that compatible blend has been achieved.