The most important property of cellulose ether solution is its rheological property. The special rheological properties of many cellulose ethers make them widely used in various fields, and the study of rheological properties is beneficial to the development of new application fields or the improvement of some application fields. Li Jing from Shanghai Jiao Tong University conducted a systematic study on the rheological properties of carboxymethylcellulose (CMC), including the influence of CMC’s molecular structure parameters (molecular weight and degree of substitution), concentration pH, and ionic strength. The research results show that the zero-shear viscosity of the solution increases with the increase of the molecular weight and the degree of substitution. The increase of the molecular weight means the growth of the molecular chain, and the easy entanglement between the molecules increases the viscosity of the solution; the large degree of substitution makes the molecules stretch more in the solution. The state exists, the hydrodynamic volume is relatively large, and the viscosity becomes large. The viscosity of CMC aqueous solution increases with the increase of concentration, which has viscoelasticity. The viscosity of the solution decreases with the pH value, and when it is lower than a certain value, the viscosity increases slightly, and eventually free acid is formed and precipitated. CMC is a polyanionic polymer, when adding monovalent salt ions Na+, K+ shield, the viscosity will decrease accordingly. The addition of divalent cation Caz+ causes the viscosity of the solution to decrease first and then increase. When the concentration of Ca2+ is higher than the stoichiometric point, CMC molecules interact with Ca2+, and a superstructure exists in the solution. Liang Yaqin, North University of China, etc. used the viscometer method and the rotational viscometer method to conduct special research on the rheological properties of the dilute and concentrated solutions of modified hydroxyethyl cellulose (CHEC). The research results found that: (1) Cationic hydroxyethyl cellulose has typical polyelectrolyte viscosity behavior in pure water, and the reduced viscosity increases with the increase of concentration. The intrinsic viscosity of cationic hydroxyethyl cellulose with high degree of substitution is greater than that of cationic hydroxyethyl cellulose with low degree of substitution. (2) The solution of cationic hydroxyethyl cellulose exhibits non-Newtonian fluid characteristics and has shear thinning characteristics: as the solution mass concentration increases, its apparent viscosity increases; in a certain concentration of salt solution, CHEC apparent viscosity It decreases with the increase of the added salt concentration. Under the same shear rate, the apparent viscosity of CHEC in CaCl2 solution system is significantly higher than that of CHEC in NaCl solution system.

With the continuous deepening of research and the continuous expansion of application fields, the properties of mixed system solutions composed of different cellulose ethers have also received people’s attention. For example, sodium carboxymethyl cellulose (NACMC) and hydroxyethyl cellulose (HEC) are used as oil displacement agents in oilfields, which have the advantages of strong shear resistance, abundant raw materials and less environmental pollution, but the effect of using them alone is not ideal. Although the former has good viscosity, it is easily affected by reservoir temperature and salinity; although the latter has good temperature and salt resistance, its thickening ability is poor and the dosage is relatively large. The researchers mixed the two solutions and found that the viscosity of the composite solution became larger, the temperature resistance and salt resistance were improved to a certain extent, and the application effect was enhanced. Verica Sovilj et al. have studied the rheological behavior of the solution of the mixed system composed of HPMC and NACMC and anionic surfactant with a rotational viscometer. The rheological behavior of the system depends on HPMC-NACMC, HPMC-SDS and NACMC- (HPMC- SDS) different effects occurred between.

The rheological properties of cellulose ether solutions are also affected by various factors, such as additives, external mechanical force and temperature. Tomoaki Hino et al. studied the effect of the addition of nicotine on the rheological properties of hydroxypropyl methylcellulose. At 25C and a concentration lower than 3%, HPMC exhibited Newtonian fluid behavior. When nicotine was added, the viscosity increased, which indicated that nicotine increased the entanglement of HPMC molecules. Nicotine here exhibits a salting effect that raises the gel point and fog point of HPMC. Mechanical force such as shear force will also have certain influence on the properties of cellulose ether aqueous solution. Using rheological turbidimeter and small angle light scattering instrument, it is found that in semi-dilute solution, increasing the shear rate, due to shear mixing, the transition temperature of the fog point will increase.