Characteristics of Natural Cellulose Fibres Extracted from Sri Lankan Rice Straw Varieties

In the recent years, natural fibres have gained greater attention to replace synthetic fibres in producing environmentally friendly green products. These are currently considered as one of the most promising areas of scientificand technological development due to strong global demand  for creating a resource circulating society. Rice is one of the largest crops in the world. Sri Lanka being an agricultural country holds twentieth position in the worldwide rice production with 2.4 and 3.9 million metric tons in the years 2017 and 2018 respectively. However, a large amount of rice straw is generated per annum as a by-product of rice production in the country. Even though rice straw is utilized in various ways, there is a possibility for a value addition by extracting its constituents such as cellulose fibres from this underutilized waste material. In this work, cellulose fibres were extracted from locally available rice straw varieties via a series of chemical treatments. Technically modified variety BG352 and traditional variety Murunkan were used for this purpose. The material obtained after chemical treatment was carefully characterized and its chemical composition was determined. Fourier transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analyses showed the progressive and complete removal of non-cellulosic constituents from the rice straw. Morphological investigation was performed using scanning electron microscopy (SEM). Thermal stability of the fibres was investigated using thermogravimetric analysis (TGA). The results showed around 26 and 33 percent cellulose fibres were extracted from rice straw varieties BG352 and Murunkan respectively.