Effects of Reaction Time on Degree of Substitution, Yield and Morphology of Carboxymethyl Cellulose from Banana Peel

Abstract

Carboxymethyl cellulose(CMC) was extracted from cultivated banana peel (BP) agricultural waste. Cellulose was first extracted from BP through delignification, bleaching and hydrolysis processes. Then, CMC was prepared by the carboxymethylation reaction using monochloroacetic acid as a modifying agent. A mixture of 30% sodium hydroxide solution and isopropanol was used as the solvent medium for etherification with reaction time of 1-5 hours. The effects of reaction time on physical appearance, chemical structure, degree of substitution (DS), percent yield (%yield) and morphology of CMC were studied. Results indicated that banana peel cellulose (BPC) powder could be extracted from BP with yield of 14.81%±7.20. CMC was successfully prepared from BPC powder and confirmed by FT-IR technique. DS and %yield of CMC increased when reaction time increased from 1 to 4 hours but decreased when reaction time reached 5 hours. Reaction time of 4 hours gave optimal DS and %yield at 0.61±0.05 and 152.65±17.93, respectively. BPC presented bulk particle shape with a dense and smooth surface. After etherification, morphology of BPC was changed to a mixture of small particles with fibrous shape and a porous rough surface.