Effect of nonadsorbing polymers on the rheology of a concentrated nonaqueous dispersion

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Langmuir; (United States)

DOI:https://doi.org/10.1021/la00049a018· OSTI ID:5325795

Reynolds, P A; Reid, C A ^[1]

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1. Courtaulds Coatings Group Research, London (England)

The rheology of a poly(methyl methacrylate) (PMMA) latex stabilized with poly(12-hydroxystearic acid) and dispersed in dodecane at a volume fraction of 0.42 was observed to deviate from near Newtonian behavior upon the addition of polyisobutylene (PIB) at high and low molecular weights, 380,000 and 2,000, respectively. The high molecular weight PIB gave the dispersion a predicted depletion-flocculated behavior, with observable phase separation and non-Newtonian shear thinning rheology, as a consequence of the additional attractive particle interaction component. Added low molecular weight PIB, however, gave comparatively much stronger non-Newtonian behavior with no observable phase separation. This behavior was observed in a region of polymer molecular weights and size comparable to that of the steric layer. The results are consistent with a steric-elastic repulsion arising from the compression of the nonadsorbing polymer chains at high particle volume fraction and not with an attractive term due to depletion flocculation.

• OSTI ID: 5325795
• Journal Information: Langmuir; (United States), Vol. 7:1; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PMMA
RHEOLOGY
CALCULATION METHODS
COLLOIDS
DATA ANALYSIS
FLOCCULATION
MOLECULAR WEIGHT
NONAQUEOUS SOLVENTS
POLYMERS
DISPERSIONS
ESTERS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
POLYACRYLATES
POLYVINYLS
PRECIPITATION
SEPARATION PROCESSES
SOLVENTS
400201* - Chemical & Physicochemical Properties