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The influence of particle size and surface coating of calcium carbonate on the rheological properties of its suspensions in molten polystyrene
Author(s) -
Suetsugu Yoshiyuki,
White James L.
Publication year - 1983
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.1983.070280421
Subject(s) - rheology , materials science , stearic acid , particle size , yield (engineering) , calcium carbonate , coating , viscosity , particle (ecology) , polystyrene , shear stress , chemical engineering , composite material , polymer , oceanography , engineering , geology
The rheological properties of polystyrene melts filled with 30 vol % of CaCO 3 particles of varying particle size are described. The influence of surface coating the particles with stearic acid is considered. Generally, the compounds with the uncoated particles exhibit viscosities which increase at ever greater rates as the shear rates decrease. It appears that these compounds exhibit yield values. Elongational flow data also suggest the existence of yield values. Difficulties exist in measurement of normal stresses in compounds with sizeable yield values. The principal normal stress difference at fixed shear stress of the PS/CaCO 3 compounds is lower than that of the PS melt. The magnitude of viscosity increases and yield values increase with decreasing particle size. Coating of particles with stearic acid results in major viscosity reductions and decreases in apparent yield values. The surface coating is most effective with the smallest particles. It presumably reduces interaction between particles and the extent of aggregation.