Open AccessEmulsion polymerization of butadiene, 3. Kinetic effects of stirring conditions and monomer/water ratio
Author(s) -
Weerts Pierre A.,
Van der Loos Jos L. M.,
German Anton L.
Publication year - 1991
Publication title -
die makromolekulare chemie
Language(s) - English
Resource type - Journals
ISSN - 0025-116X
DOI - 10.1002/macp.1991.021920909
Subject(s) - monomer , emulsion polymerization , polymerization , nucleation , diffusion , particle (ecology) , emulsion , phase (matter) , polymer chemistry , limiting , chemical engineering , kinetic energy , chemistry , polymer , materials science , thermodynamics , organic chemistry , physics , mechanical engineering , oceanography , quantum mechanics , engineering , geology
The stirring speed n influences the emulsion polymerization of butadiene, (1) by reducing the effective emulsifier concentration [E] eff available for particle nucleation and stabilization at high n , and (2) by limiting diffusion of monomer to the latex particles at low n . The large density difference between butadiene and water promotes the breaking up of droplets at high n , while the same condition constitutes a large driving force for (partial) phase separation at low n . Increasing the monomer/water ratio at constant [E] decreases [E] eff , and thus the final particle number. At monomer volume fractions >0,6 mixed emulsions are likely to be formed initially, reducing [E] eff even further. In the presence of mixed emulsions, polymerization in the monomer phase may no longer be neglected, giving rise to a complex kinetic behaviour.
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