Degradation Behaviors of Different Blends of Polylactic Acid Buried in Soil

Polylactic acid (PLA), as the biodegradable polymer becomes more attention as a green material for industrial applications. Lipase-catalysed polymerization with Lecitase Ultra and Lipozyme TL IM were applied to synthesize PLA to decrease the chemical-catalysts utilization which having toxicity interferes in products. PLA products were characterized by end group/HPLC analyses for Mn/Mw determination. The results indicated that low molecular weight PLA could be successfully produced from commercial lactic acid by using the commercial lipases. With using Lipozyme TL IM as biocatalyst, obtainable Mn and Mw of PLA were 7,933 Da and 194 Da, respectively. For Lecitase Ultra used as biocatalyst obtainable Mn and Mw of PLA were 8,330 Da and 216 Da, respectively. Subsequently, the resulting PLA products from this method were prepared as PLA films blended with commercial PLA beads varying the blending ratios by casting on glass plate. Their degradable behaviors were studied under controlled soil burial laboratory conditions. The characteristics of PLA blend films were analyzed using visual observations, measuring weight loss, DSC and FTIR analysis. The results observed that the different blends ratios of PLA films showed more flexible than pure PLA film. Besides, the different blends of PLA films were disintegrated in soil within the short burial time.