Preparation of Lignocellulosic Film by Dissolving of Rice Straw in Alkaline Solution

Due to the limited oil resources and environmental effects of coating films from petroleum and plastic materials, today there is special attention to the production, optimization and consumption of natural biopolymers. The use of biomass as a sustainable and renewable material for the production of films from lignocellulosic sources such as wheat straw and rice straw has increased in recent years. In this study, the preparation of a biofilm based on dissolution of rice straw was investigated. Initially, sodium hydroxide was used in different concentrations to dissolve rice straw. Various treatments such as freezing-thawing and acid pretreatment were used to improve the dissolution of rice straw. Based on the calculation of dissolution yield, good results were not obtained for dissolving rice straw in sodium hydroxide solution. However, by applying chemical acid pretreatment, soda/urea solution and freezing-thawing sequence, dissolution efficiency was improved and films were produced using the molding method. The physical and chemical properties of the prepared films were analyzed by analysis methods including the transparency of the solution as an indicator of the quality of dissolution, optical microscope and scanning electron microscopy and EDX test. The results showed that the resulting film was dissolved in acid pretreated rice straw and then dissolved in soda/urea solution with optical properties, uniformity and topography of a suitable surface that can be used as a coating in the packaging industry.