Rheological behavior of cyanoethyl celluloses in aqueous solutions

Abstract

Water-soluble cyanoethyl cellulose (CEC) samples were synthesized by homogeneous reaction of cellulose with acrylonitrile in LiOH/urea aqueous solutions. The dynamic viscoelastic property of CEC with different degree of substitution (DS) in water at different temperatures and concentrations were investigated. At low concentrations, the CEC solutions displayed liquid-like behavior with G 0 smaller than G 00 at low frequencies; while the curves of G 0 and G 00 intersected at the middle of the frequency range at higher concentration, indicating an existence of chain aggregation and entanglement network. The gelation temperature (T gel ) was determined from the point of intersection in tan d versus temperature (T) at different frequencies, indicating the validity of Winter-Chambon criteria. It was found that T gel increased with increasing DS, and that the exponent (n) values at the gel point decreased with increasing DS. The heatingcooling process proved that the sol-gel transition for CECs in water was thermally irreversible. The AFM images revealed that the particles packed loosely together to form gel aggregates. Moreover, the Maxwell model with four elements was used to describe the frequency dependencies of G 0 and G 00 for CEC in aqueous solution.

Direct dissolution and spinning of the agricultural waste of corn straw pulp

“…As is well known, wood pulp remains the most important raw material source for the processing of cellulose. However, most of it is used for paper making, while only very small amounts are used for the production of fibers as well as for the synthesis of cellulosic esters and ethers (Li et al 2012). Though the vast majority of garments and textile products with non-synthetic components are (≤60 °C) and the dissolution rate is more rapid (≤1h).…”

Solvent-dependent rheological behavior of concentrated solutions of a cationic acrylic terpolymer containing self-assembled chains

“…The rheological behavior of the terpolymer solution in the solvent mixture, in contrast to that for the acetone solution, is not a usual behavior for concentrated solutions of polar polymers (17)(18)(19). An initial peak followed by a flat region and a final increase can be observed in Figure 4.…”

Homogeneous cyanoethylation of cellulose with acrylonitrile in a CO2 switchable solvent

“…21 Therefore, much effort has been made for the homogeneous cyanoethylation of cellulose with a reduced amount of AN for the synthesis of CEC with a tunable DS and uniform substitution distribution. 22–29…”