Extraction and Characterization of Nanocellulose for Polyvinyl Alcohol Based Nano-composite Application

Abstract

Nowadays, there are many polymeric materials that are used for different applications like packaging, constructions, medical and automotive devices. The majority of these materials are produced from fossil fuel-based resources which are non-renewable and affect the environment. Bio-composite materials which are composed of two or more different materials that have improved properties are the promising option to replace the non-renewable plastic materials. The bio composite materials can be produced by reinforcing cellulose, nanocellulose, nano clay, and others into the polymer matrix. The cellulose was extracted from teff straw by hot water treatment, acid-chlorite delignification, and alkaline hydrolysis process respectively. The process parameters of alkaline hydrolysis were optimized by response surface methodology (central composite design). The optimum values of temperature, time and sodium hydroxide concentration were 57.676 , 1hour and 4(w/v) % respectively. The maximum cellulose yield was 78.748% and the nano cellulose yield was 42.87%. The nano cellulose particles were extracted from the cellulose by acid hydrolysis process (48%v/v) at 35 for 30 min. The characterization of nano cellulose was done by using Fourier-transform infrared spectroscopy, dynamic light scattering, and x-ray diffraction to determine the functional group, particle size distribution and crystallinity respectively. The Fourier-transform infrared spectroscopy result shows that the reduction and total removal of lignin, hemicellulose and other amorphous parts found in teff straw. The average particle size was found to be 102.6 nm with a polydispersity index of 0.047. The crystallinity index of cellulose and nano cellulose was 60.80% and 77.18% respectively. The nanocellulose extracted was successfully reinforced into poly (vinyl) alcohol to illustrate the improvement in water absorption capacity, tensile strength, elongation at break and thermal stability of polyvinyl alcohol. Different ratios of nanocellulose loading were used to see the effects of nanocellulose loading on properties of poly (vinyl) alcohol. The equal amount of cellulose and untreated teff straw were also reinforced with poly (vinyl) alcohol to see the effect of reinforcement type.