|
|||||
|
|
Homo- and heteroflocculation of papermaking fines and fillers |
|
| Authors: | Jana Porubsk Bob Alince Theo G M van de Ven |
| Institution: | a Department of Chemical Engineering, Pulp and Paper Research Centre, McGill University, Montreal, Que., Canada H3A 2A7 b Department of Chemistry, Pulp and Paper Research Centre, McGill University, Montreal, Que., Canada H3A 2A7 c Paprican, Pulp and Paper Research Centre, McGill University, Montreal, Que., Canada H3A 2A7 |
| Abstract: | The effects of cationic polyethylenimine (PEI) on the colloidal stability of anionic fines (microcrystalline cellulose or thermomechanical fines), fillers (clay) and their mixtures in deionized and tap water were investigated, using a photometric dispersion analyzer. Measurements confirmed that PEI flocculates all used materials by charge neutralization. As expected, higher additions of PEI lead to electrostatic stabilization of microcellulose and clay suspensions, but it was not possible to stabilize the suspension of fines using high additions of PEI. This is ascribed to the mechanical entanglements of fibrillar fines. In tap water, much more PEI is needed to reach optimum flocculation conditions than in deionized water. Heteroflocculation between PEI-coated clay and fines takes place with a rate which, for high fines concentration and a constant clay concentration, is independent of fines concentration. A theoretical model for the heteroflocculation of fines with PEI-coated clay has been developed, which explains the observed trends. In essence, clay particles can act as bridging agents for fines flocculation. |
| Keywords: | Polyethylenimine Fines Fillers |
| 本文献已被 ScienceDirect 等数据库收录！ | |