SHEAR-INDUCED AGGREGATION OF CARBOXYLATED POLYMER LATICES

被引:22
作者
HUSBAND, JC [1 ]
ADAMS, JM [1 ]
机构
[1] ECC INT LTD,RES & DEV,JOHN KEAY HOUSE,ST AUSTELL PL25 4DJ,CORNWALL,ENGLAND
关键词
CARBOXYLATED LATEX; ORTHOKINETIC AGGREGATION; CRITICAL SHEAR RATE; HYDRODYNAMIC FORCE; DLVO REPULSIVE FORCE;
D O I
10.1007/BF01095060
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Orthokinetic flocculation of latex particles containing high levels of surface carboxylation was studied by shearing for short times in a rotational viscometer and measuring changes in particle size using photon correlation spectroscopy. Results can be interpreted in terms of a comparison between the DLVO repulsive force between a pair of particles and the hydrodynamic shear force opposing it. This enables a prediction of the critical shear rate, gamma(crit), required to initiate aggregation. Experimental and calculated values of gamma(crit) showed good agreement. The stability of the carboxylated latices under shear was much reduced at pH values > 7 when the surface groups are ionised. The increase in suspension viscosity with pH was shown to be critical in determining the onset of aggregation via hydrodynamic forces.
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页码:1194 / 1200
页数:7
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