Cellulose extraction from rice straw waste for biodegradable ethyl cellulose films preparation using green chemical technology

Abstract

A green process was devised to effectively extract cellulose from recycled rice straw waste, subsequently ethylating and modifying it into ethyl cellulose (EC), and ultimately blending the EC with ethanol to obtain biodegradable films. The optimal process conditions at each stage were investigated. An assessment was conducted on the crystallinity and thermal stability of rice straw cellulose (RSC), the degree of substitution of EC, and the biodegradability and mechanical properties of EC-ethanol films. The results demonstrated the following: The optimal process conditions resulted in a 95.73 % yield of extracted RSC, a type I crystalline structure, a 31.20 % increase in relative crystallinity, and thermal stability with a main weight loss peak at 340 °C. Under ideal ethylation conditions, the EC production reached 79.60 %, while the degree of substitution ranged from 2.0 to 2.5. After being landfilled in soil for 100 days, the EC-ethanol films degraded at rates of 6.77 %, 4.78 %, and 3.13 % (film concentrations were 0.02, 0.04, and 0.06 g/mL (w/v, EC/ethanol), respectively). Based on the analysis of the films' FT-IR and SEM images, it was concluded that the EC-ethanol films exhibit favorable biodegradability. Moreover, the tensile strength of 0.04 g/mL film reaches up to 44.60 MPa. Hence, the EC-ethanol films in this research could be an environmentally friendly and sustainable alternative to plastic films.