Electrostatically stabilised lattices having various sizes were used to study the thickening of alkalissolutable ethyl acrylate-methacrylic acide copolymer (50 wt. % of the acid; MW = 0.78 x 105, 4.36 x 105 and 11.6 x105).
It was found that the effect increases with the molecular weight of the copolymers and with the decreasing size of the latex particles.
The pronounced tendency towards nondredging flocculation and phase separation suggest that the thickening effect of the materials results from depletion (volume restriction) flocculation rather that depletion stabilisation.
The role of the effective volume fraction of the dissolved copolymer as a variable which controls the rheological properties of the thickened lattices was tested experimentally.
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