Temperature‐dependent behavior of polyethylene oxide in papermaking suspensions

Abstract

AbstractThe adsorption of polyethylene oxide (PEO) on chemi‐thermo‐mechanical pulp (CTMP), clay, and chalk suspensions was investigated at 303 and 343 K. These conditions corresponded to points below and above the critical solution temperature (CST) of a 0.005 mass % polyethylene oxide solution in the presence of 2 mol/L of KCl. The PEO adsorption on CTMP and clay particles was also studied at different initial PEO concentrations up to 50 mg/L. PEO adsorbed onto papermaking furnish particles at both temperatures, but the adsorbed amount was found to be larger above the CST in all systems. At 303 K it increased with the increase in PEO added to the system until it reached a plateau, but at 343 K it increased with the increase in PEO added in all the range of PEO concentrations up to 50 mg/L. The state of aggregation of PEO‐clay and PEO‐chalk suspensions was also studied by monitoring fluctuations in the intensity of light transmitted through the suspension. These measurements indicated a strongly temperature‐dependent aggregation. It was concluded that the entropically driven phase separation leads to enhanced aggregation, which in turn favors the retention of fiber fines and clay filler.