Assessment of different plasticizer – polyhydroxyalkanoate mixtures to obtain biodegradable polymeric films

Abstract

The elaboration of films from biodegradable polymer polyhydroxybutyrate was studied with 4 main plasticizers at variable concentrations: polyethyleneglycol, lauric acid, glycerol and epoxidized soy bean oil. An evaluation of the state of the art in the properties of commercial PHB (polyhydroxybutyrate) and necessary additives was elaborated in order to establish the experimental design to develop a polymeric film. Also, the qualitative evaluation of overall brittleness showed a variability due the nature and concentration of plasticizer. The influence of plasticizers on polymeric films was evaluated with gas chromatography (GC/MS) and Infrared Spectroscopy. The measurements were made on samples from different stages of the process in order to evaluate PHA (polyhydrixyalkanoate) purity. Measurements from the gas chromatography studies show the purity of the inicial fermentation broth (59.87%) , after the extraction with SDS and sodium hypochlorite (65%) and in mixtures with PEG (58.15%). From a general perspective, polyethyleneglycol (PEG) lower the material frailness and does not modify the Infra Red Spetrum as well as the Crystallinity Index (CI) in comparison with a standard commercial sample (70%+)