Rheolojical behaviour of carboxymethyl cellulose obtained from orange peel cellulose

SUMMARY Master Thesis RHEOLOGICAL BEHAVIOUR OF CARBOXYMETHYLCELLULOSE OBTAINED FROM ORANGE PEEL CELLULOSE Fevzi YAŞAR Fırat University Graduate School of Natural and Applied Sciences Department of Chemical Engineering 2005, Sayfa: 84 Carboxymethylcellulose is a copolymer of P-D-glucose and P-D- glucopyranose which are linked via p~l,4-glucosidic bonds. Carboxymethyl cellulose is the most important water-soluble cellulose derivative, with many applications in the food industry and in cosmetics, pharmaceuticals, detergents, etc. Carboxymethyl cellulose is used a thickener or a flocculating agent in various applications. The effects of temperature and concentration on the viscosity of cellulose from orange peel were examined at different temperatures (20, 30, 40, 50, 60 °C) and concentration levels (1, 2, 3, 4, 6, 8, 10 kg/m3). Twenty-eight different model equations that describe the combined effects of temperature and concentration on the viscosity were derived. The orange peel cellulose was converted carboxymethyl cellulose by the carboxymethylation. The flow behaviour of carboxymethylcellulose from orange peel cellulose was determined using a rotational viscometer at a temperature rangeVI of 10-50 °C and carboxymethyl cellulose concentrations of 10- 35 kg/m3. Three models were used to predict the flow behaviour of carboxymethyl cellulose, namely, the power law, Bingham, and Casson models. The power model adequately described well the flow behaviour of carboxymethyl cellulose at different temperatures and concentrations. The consistency coefficient decreased with temperature and increased with the concentration. It was found that the flow behaviour of carboxymethyl cellulose solutions was pseudoplastic. The expression for the combined effect of temperature and concentration on the apparent viscosity of carboxymethyl. cellulose was given. Regarding the time-dependent rheological behaviour, it was found that the examined carboxymethyl cellulose solutions were adequately described by the Weltman model and found to be thixotropic. Key Words: Orange peel, cellulose, carboxymethyl cellulose, extraction, rheology