Synthesis and characterisation of Carboxymethyl Cellulose (CMC) from wheat bran and its application as PE/PET/CMC film

Carboxymethyl cellulose (CMC) is one of cellulose derivatives that can be produced from agro-industrial waste. This biopolymer can be used as ingredient to develop a food packaging. The main aim of this study was to utilise wheat bran produced from milling process into carboxymethyl cellulose. Besides, the purpose of this research is to investigate the effectiveness of CMC as a potential biopolymer that can be used to produce film for packaging materials. CMC from wheat bran was prepared using sodium chloroacetate and NaOH. In this study, six different concentrations of NaOH that ranged from 5% to 30% (w/v) were used with the addition of isopropanol as the supporting medium in etherification process. This process was conducted at 85 degree Celcius for 3 hours. CMC obtained in this study was mixed with distilled water and glycerol and applied on PE/PET film to produce PE/PET/CMCS and PE/PET/CMCD films. For CMC, the effect of NaOH used during etherification on yield and physicochemical properties such as degree of substitution (DS) value, CMC content, molecular weight, colour, viscosity and surface morphology of CMC were analysed. CMC extracted with 10% and 15% (w/v) NaOH exhibited the highest value of DS with 0.84 and 0.83 respectively while 61672 and 43012 Da for molecular weight. All CMCs obtained in this study exhibited brighter, reddish and yellowish in colour with moisture content of lower than 8%. On the other hand, physical characteristics of PE/PET/CMC films such as film thicknesses, moisture content, film solubility, moisture absorption, colour, contact angle of films, water vapour permeability and film morphology were investigated. From the results, PE/PET/CMC15D showed the highest values for film thickness, moisture content and film solubility. All films produced were transparent but a bit yellow in colour. PE/PET/CMCS showed higher tensile strength and lower elongation at break compared to PE/PET/CMCD films. However, PE/PET/CMCD exhibited better water vapour permeability lowers than PE/PET film. From the findings obtained in this study, agriculture waste such as wheat bran can be used as a potential source of biopolymer that is capable to be used as a component in multilayered films.