Ebru Tektemur , Emine Bayraktar , Mehmet Saçak
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Journal : International journal of Horticulture, Agriculture and Food science(IJHAF)
PLA is getting more important in terms of green chemistry and concern for the environment. The starting material for this polymer, lactic acid, can be made by a fermentation process using 100% annually renewable resources. Poly (L-lactic acid) (PLLA) was produced via melt polycondensation method in this study. Effects of catalyst type (Sb2O3, SnCl2 and TSA binary system, Sn(Oct)2) on the production of PLLA was investigated. The binary system of using SnCl2 with the amount of 0.3 (wt %) based on oligolactic acid (OLLA) with an equimolar ratio to p-toluene sulfonic acid (TSA) was found the most efficient catalyst in enhancing polymers molecular weight. In order to investigate polycondensation strategy, different polymerization pressure and progressive pressure drop program was examined. It was found that the higher molecular weights were obtained with progressive pressure dropping relative to applying low pressure on polycondensation . Molecular weight of PLLA was obtained as 64000 Da at 2 h at 30 mm Hg, 3 h at 20 mmHg and 3 h at 10 mmHg. Also ultrasound was applied to OLLA and catalyst mixture before polycondensation. It reached to 77600 Da by applying ultrasound at 3 min at the same reaction conditions.