Rheological properties of cellulose-chitosan-phosphoric acid systems in different phase states

• Published in: Polymer Science. Series A Vol. 56; no. 2; pp. 137 - 145
• Main Authors: Grinshpan, D. D., Gonchar, A. N., Savitskaya, T. A., Tsygankova, N. G., Makarevich, S. E.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2014; Springer Nature B.V
• Subjects: Chemistry; Chemistry and Materials Science; Gels; Mathematical models; Natural Polymers; Polymer Sciences; Rheological properties; Shear flow; Shear rate; Spinning; Steady state; Streams; Polymer Science Series; Cellulose Solution; Chitosan; Shear Rate; Cellulose
• ISSN: 0965-545X; 1555-6107
• DOI: 10.1134/S0965545X14020059

Rheological properties of 7.0–9.1% cellulose-chitosan suspensions, solutions, and gels in aqueous phosphoric acid were examined in various modes of shear flow in the range 0.15–100 s −1 at 268–323 K. During steady state flow, the appearance of a quasi-Newtonian region was detected at shear rates between 20 and 40 s −1 owing to orientational ordering of macromolecules in the stream. Under the conditions of transient shear flow at a constant shear rate, rheopexy was observed in both cellulose solutions and cellulose-chitosan solutions. The thixotropic behavior of cellulose-chitosan suspensions, spinning solutions, and gels was characterized during a sharp drop of shear rate from 0.15 to 10 s −1 , that is, under conditions modeling the processes of transport and extrusion of spinning solutions.