Flow behaviours of cellulose and carboxymethylcellulose from grapefruit peel

Flow Behaviours of Cellulose and Carboxymethylcellulose from Grapefruit Peel Carboxymethyl cellulose (CMC) is the most widely used cellulose ether, with applications in the food, detergent, paper, textile, pharmaceutical and paint industries as thickener or a flocculating agent. The effects of temperature and concentration on the viscosity of cellulose from grapefruit peel were examined at different temperatures (10, 20, 30, 40, 50, 60 oC) and concentrations (1, 2, 4, 6, 8, 10 kg/m3). The effect of concentration and temperature on the viscosity of cellulose from grapefruit peel were examined by utilizing various models describing the combined effects of temperature and concentration on the viscosity. At various stages of cellulose production that concentrations and temperatures changed, the best model among those models may be used to estimate the viscosity of cellulose from grapefruit peel in the range of temperatures and concentrations studied. The apparent viscosity of CMC from grapefruit peel cellulose was measured at differents temperatures (10-60 oC) and concentrations (15-35 kg/m3) by using a rotational viscometer and the flow behaviours of samples were determined. Apparent viscosity decreased with increasing shear rate. Apparent viscosity increased with an increase in concentrations for all temperatures and decreased with inreasing temperature for all concentrations. The Arrhenius equation was used to describe the temperature dependence of viscosity. The power law, Bingham and Casson models were used for description of flow. The power model given a good fit for the experimental data of CMC at different temperatures and concentrations. The consistency coefficient and flow behaviour index of CMC solutions were calculated bu using the power-law model. It was found that the CMC solutions showed a non-Newtonian pseudoplastic behaviour. The equations developed to describe the combined effect of temperature and concentration on the apparent viscosity of CMC may be used to estimate the changes in the viscosity of CMC from grapefruit peel in the range of temperatures and concentrations studied. Keywords: Grapefruit peel, Cellulose, Carboxymethylcellulose, Flow behaviour