Optimization of carboxymethylcellulose production

The aim of the study was to obtain water soluble carboxymethylcellulose (CMC) with a high degree of polymerization (DP gt 600) and high degree of substitution (DS gt 800), in industrial conditions, from easily degradable eucalyptus cellulose. The influence of temperature and of the NaOH:MCAA molar ratio cellulose on the structural and degradative changes in cellulose macromolecules during the process was investigated using ethanol as the reaction medium. The structural transformations during alkalization and etherification were investigated by X-ray diffraction. The degradative changes in the macromolecule were followed by determining the degree of polymerization. The degree of substitution and other chemical characteristics were determined by standard analytical methods. The thermal behaviour of the samples was studied by using a Perkin Elmer DSC-2 instrument. The rheological properties of the CMC solutions were also studied

Viscoelastic properties of Na-carboxymethylcellulose solutions

The rheological characteristics of 5% solutions of Na-carboxymethylcellulose (CMC)I of various origin were investigated. Depending on the molar mass (1.25-1.94 x 10(5) g mol(-1)), i.e., the degree of polymerization (545-851) and degree of substitution (0.748-1.039), as well as the electrolyte (NaCl) content (0.55-36.40%), it was found that microgel particles appear in some cases, while in other cases there are entanglements or isolated particles of CMC macromolecules in solution. Stronger macromolecular interactions were observed when the degree of polymerization was greater than about 600 and the degree of substitution was higher than approximately 0.8. The rheological characteristics of the investigated samples are discussed in relation to the macromolecular structure (defined by X-ray powder diffraction and FT-IR spectroscopy) in the solid state