Physical properties of methylcelluloses in relation with the conditions for cellulose modification

cited By 75International audienceWater-soluble methylcellulose (MC) samples were synthesized by a new homogeneous reaction using DMAc/LiCl as solvent, a dimsyl sodium solution as activator and CH3′ as alkylating reagent. Different degrees of substitution were obtained (0.9 < DS < 2.2). A commercial MC (D̄S̄ =1.7) was also studied. The structural characterization of the samples was carried out using 13C-NMR and h.p.l.c. measurements. Rheological and steric exclusion chromatography studies in the dilute regime were performed as a function of the temperature and the properties of the samples were compared. According to the DS value, two different behaviours were observed. For DS > 1.5, interactions occur for T>45°C. If D̄S̄ < 1.5 there is no clear evidence for aggregation. © 1997 Elsevier Science Ltd. All rights reserved