Biodegradation of Levan Polymer/Poly(Lactic Acid)(PLA)Blend

摘要

Poly(lactic acid)(PLA)is a biodegradable thermoplastic.With low elongation and poor degradation properties,many approaches have been developed to overcome these limitations,including copolymerization,blending and plasticizing to improve the mechanical properties.Levans are a group of fructan polymer with act as a good co-polymer,which can be produced by levansucrase using sucrose as substrate.In this study,co-solvent for levan/PLA blend film preparation,thermal properties and biodegradation of levan/PLA blend film were investigated.The result found that DMSO and CH2Cl2 were suitable for the co-solvent process.The Levan/PLA blend films were prepared with levan contents of 0,0.5,1,2,5,10,15 and 20 wt%.The biodegradation of levan/PLA blend film in vitro and in soil conditions showed that 15 wt% levan/PLA at 7 days and 10 wt% levan/PLA at 21 days were the highest weight loss,respectively.In addition,the morphological changes in the Levan/PLA blend film and thermal properties were analyzed by Scanning electron microscope(SEM)and Differential scanning calorimetry(DSC).The results from DSC present that the melting temperature of PLA was slightly decreased with increasing levan contents.Moreover,the holes from degradation were larger and the rougher surfaces were observed with levan contents.