430 J. Eng. Tec hno l. Sc i., Vo l. 48, No . 4, 2016, 430-441 Received December 16 th , 2015, Revised April 8 th , 2016, Accepted for publication September 1 st , 2016. Copyright ©2016 Published by ITB Journal Publisher, ISSN: 2337-5779, DOI: 10.5614/j.eng.technol.sci.2016.48.4.5 Improvement of Properties of Poly(L-lactic acid) through Solution Blending of Biodegradable Polymers Johnner P. Sitompul, Rizky Insyani, Daniel Prasetyo, Hermawan Prajitno & Hyung Woo Lee* Department of Chemical Engineering, Faculty of Industrial Technology Institute of Technology Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia *E-mail: leehw@che.itb.ac.id Abstract. This study concerns the improvement and enhancement of the properties of poly(L-lactic acid) (PLLA) through simple solution blending of pure PLLA with different kinds of biodegradable polymers. Synthesized PLLA was blended with synthesized poly(D,L-lactic acid) (PDLLA) or poly(ethylene glycol) (PEG) at various composition ratios in a solvent mixture of dichloromethane/ethanol at room temperature to produce dipolymer. The polymer-blend properties were analyzed using FTIR, DSC, UTM data and an enzymatic degradation test was conducted. It was found that PLLA blend films were obtained with limitation of the second polymer content up to 20% (w) through solvent casting. From the DSC data, two different melting temperature peaks showed that stereocomplex formation occurred during polymer precipitation for all PLLA/PDLLA blends, while only one single melting temperature peak appeared in the PLLA/PEG blend. Regarding the mechanical properties, the PLLA/PEG blend showed better performance with an improvement of the mechanical strength by around 11.18% and an improvement of the elongation at break by around 89% compared to pure PLLA. Furthermore, after the 48-hour enzymatic biodegradability test, the PLLA/PEG blends showed improvement of biodegradability with 21.88% of sample weight-loss compared to 2.53% for pure PLLA. Keywords: biodegradability; mechanical properties; polylactic acid; PLLA/PDLLA; PLLA/PEG; solution blending; stereo-complex. 1 Introduction Consumption of conventional plastics as raw materials is increasing considerably from year to year along with the growing human population. Conventional plastic production contributes to petroleum consumption, CO 2 emission and non-degradable plastic waste. In the present millennium, demand and development of biomass-based polymers has increased significantly to substitute conventional plastics. Polymers made from biomass can reduce global warming by diminishing carbon emissions, reduce our carbon footprint and further improve carbon life-cycle assessment. This can occur because the synthesis process and raw materials of biomass-based polymers do not require