Cellulose, additives Wetting

Controlling fluid loss loss is particularly important in the case of the expensive high density brine completion fluids. While copolymers and terpolymers of vinyl monomers such as sodium poly(2-acrylamido-2-methylpropanesulfonate-co-N,N-dimethylacrylamide-coacrylic acid) has been used (H)), hydroxyethyl cellulose is the most commonly used fluid loss additive (11). It is difficult to get most polymers to hydrate in these brines (which may contain less than 50% wt. water). The treatment of HEC particle surfaces with aldehydes such as glyoxal can delay hydration until the HEC particles are well dispersed (12). Slurries in low viscosity oils (13) and alcohols have been used to disperse HEC particles prior to their addition to high density brines. This and the use of hot brines has been found to aid HEC dissolution. Wetting agents such as sulfosuccinate diesters have been found to result in increased permeability in cores invaded by high density brines (14). 

Infrared microspectroscopy is used in the pulp and paper industry73 for compositional analysis of pulp, wet end and size press chemical components in paper contaminants, additives and cellulose, and inks. Wilkinson et al.74 studied ink-paper interactions to discern changing ink properties when applied to paper. In this work, the authors employed synchrotron-based reflectance infrared microspectroscopy as a rapid, direct and nondestructive analysis approach for the study of inks on paper. The authors of this chapter expect infrared imaging to gain popularity as a technique for paper analysis. 

For a recent review on a critical evaluation on classical methods see Fardim et al. [123]. In addition to the wet chemical methods, FTIR spectroscopy and ESCA [124,125] techniques have been applied to quantify carboxyl groups in cellulose and pulp. In case of FTIR, satisfactory results in comparison to wet chemical analysis could only be obtained with carboxyl-rich samples [ 126— 128],... 

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