UV Spectroscopic Monitoring Method for Real-Time Wet-End Control of Polymeric Adsorption in Aqueous Fibrous Suspensions

Abstract: The objective of the present study was to establish a spectroscopic method for monitoring two poly-meric additives in an aqueous fibrous suspension. The polymers used in the study were polyamide epichlor-ohydrin (PAE), wet-strength resin, and an imidazolinium quaternary (IZQ) softener, which are commonly used in tissue manufacturing. With a single additive (PAE or IZQ), the concentrations were proportional to the UV absorptions at wavelengths of 314 and 400 nm, respectively. With both polymers present, the concentration were determined by multi-wavelength spectral analysis combined with a PLS calibration method. The spectro-scopic analysis data indicated that the bulk of the additives adsorbed within a few minutes. Higher additive charges led to higher level adsorption equilibria. Co-ionic dual polymer addition resulted in a reduced adsorp-tion of each species resulting from a strongly competitive adsorption effect. The spectroscopic method to de-termine PAE and IZQ adsorption may be used as a tool for wet-end chemical process control in the paper industry