Abstract

• Pineapple leaves are one of the abundantly available waste materials and used for production natural fibres. Cellulose was isolated from pineapple leaf fibres (PALF) by mechanical and chemical treatments using alkaline, inorganic salts and acids. Cellulose was then converted to carboxymethyl cellulose by an alkalization and etherification process, using various concentrations of sodium hydroxide (10 %, 20 %, 30 % and 40 % w/v) and sodium monochloroacetate (SMCA), in isopropyl alcohol medium. All the carboxymethyl cellulose (CMC) obtained from various concentrations of NaOH were investigated on yield percent, solubility of water and degree of substitution to get the optimum CMC. These results indicate that the optimum reaction of alkalization was reached at 30 % NaOH. The physicochemical properties of optimum CMC such as moisture content, pH and solubility were also determined. Characterization of raw sample, bleached sample, cellulose and CMC were carried out by analyzing the XRD pattern, spectra of FT IR and SEM photomicrographs. The XRD analysis showed that the native cellulose was transformed into an amorphous phase, as evidenced from the characteristic peaks that had almost disappeared. FT IR analysis indicated that, in addition to the main characteristic bands of cellulose, CMC showed new characteristric absorption bands at 1591 and 1413 cm-1 , which are associated with the anti-symmetric and symmetric stretching vibrations of COO- , respectively. In SEM analysis, it can be seen the significantly changes from cellulose to CMC. These results confirmed the carboxymethylation process from cellulose.