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Water‐soluble polymers as retention aids in a model papermaking system. I. Polyacrylamides
Author(s) -
Howard G. J.,
Hudson F. Lyth,
West Jeremy
Publication year - 1977
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1977.070210101
Subject(s) - titanium dioxide , polymer , papermaking , polyacrylamide , chemical engineering , adsorption , flocculation , cellulose , cellulose fiber , polymer chemistry , chemistry , materials science , composite material , organic chemistry , engineering
Abstract A series of polyacrylamides covering a wide molecular weight range were synthesized and employed as retention aids in a model papermaking system of cellulose fibers and titanium dioxide. The ability of the polymer to increase the proportion of added titanium dioxide that is retained in the formed paper sheet is strongly dependent on molecular weight, but not on pH. Adsorption isotherms on both pigment and fibers are strongly molecular weight dependent. Polyacrylamides have no more than a weak flocculating effect on fiber suspensions and stabilize dispersions of titanium dioxide. However, with mixed dispersions of fibers and pigment, in the same ratio (10:1) as in paper formation, strong coflocculation is evidenced by the higher molecular weight polyacrylamides. In this model system pigment retention is a consequence of a heteroflocculation by adsorbed polymer bridging between the particles of titanium dioxide and cellulose fibers, possibly augmented by improved filtration in the forming sheet. Electrostatic effects appear to be unimportant in the system under study.