Thermosensitive silica-pluronic-starch model coating dispersion-part I: The effect of Pluronic block copolymer adsorption on the colloidal stability and rheology
2016 (English)In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 506, 245-253 p.Article in journal (Refereed) Published
The colloidal stability of a model paper coating dispersion consisting of silica particles, Pluronic F127, starch and glycerol was studied with respect to PF127 temperature responsiveness and its adsorption on the silica surface. Rheological characterization of this system in order to extract structural information for the wet suspension state was accomplished in terms of rotational tests. The analysis, done by Krieger-Dougherty model and the elastic floc model for all flow curves at three different temperatures, 20 degrees C, 25 degrees C and 30 degrees C, and at different particle volume fractions (phi between 0 and 0.31), revealed that the structure of the system changes. Two regions with different behaviour and a plateau region at particle volume fraction of phi similar to 0.16 were observed. At phi <= 0.16 temperature was affecting the suspension structure. By rising the temperature the well dispersed suspension at 20 degrees C transformed to flocculated one, where the higher the temperature was, more open floc structures were detected in terms of degree of flocculation parameter, C-fp, but at the same time with increasing the particle concentration the flocs got denser according to the calculated. At phi >= 0.16, there were not detected major structural differences by changing temperature or particle concentration. At phi similar to 0.16 a plateau in yield stress values was observed. The behaviour of the investigated model coating suspension was discussed in terms of shear stresses and C-fp.
Place, publisher, year, edition, pages
2016. Vol. 506, 245-253 p.
Thermosensitive, Colloidal silica, Pluronic triblock copolymer, PEO-PPO-PEO triblock copolymer, Gel, Adsorption, Rheology, Viscosity
Research subject Chemical Engineering
IdentifiersURN: urn:nbn:se:kau:diva-47139DOI: 10.1016/j.colsurfa.2016.06.032ISI: 000382591100028OAI: oai:DiVA.org:kau-47139DiVA: diva2:1045506