Synthesis and characterization of carboxymethyl cellulose from pineapple leaf and kenaf core biomass: a comparative study of new raw materials

In present study, a simple, scalable, cost effective, and single step of carboxymethylation was conducted to functionalize cellulosic fibers from pineapple leaf (PALF) and kenaf core (KCF) into carboxymethyl cellulose (CMC) product. During the surface modification, an etherification process was applied to prepare CMC from cellulosic fibers using monochloroacetic acid and sodium hydroxide as the solvent medium. The obtained CMC products were characterized using various advanced techniques like SEM, EDX, FTIR, XRD, DSC, and particle size analysis. The FTIR analysis revealed the occurrence of a new absorbed peak at around 1620.2 cm⁻¹, reflecting to the vibrational stretch of carboxyl groups (COOH) and another observed peak at 1423.8 cm⁻¹ was assigning to the salts of carboxyl groups for carboxymethyl cellulose (COONa). Meanwhile, the XRD results confirmed the reduction of crystalline structure for CMC after the synthesis process. The native cellulose characteristic peaks for CMC became almost unobservable due to their transformation into an amorphous structure. Besides this, the SEM examination presented the CMC powder with ruptured surface morphology, while showing cracked and deformed structure owing to the breakdown of the CMC polymer chain after reaction with 40% NaOH concentration. Furthermore, the EDX analysis showed highly pure cellulose elemental composition in each fiber sample after chemical treatments. Moreover, the thermal behavior was stable for both CMC product from PALF and KCF by showing a relatively uniform horizontal curve of DSC pattern. Therefore, the obtained CMC product has potential used for pharmaceutical and food additives application fields.