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Nonequilibrium morphology development in seeded emulsion polymerization. IV. Influence of chain transfer agent
Author(s) -
Stubb Jeffrey M.,
Sundberg Donald C.
Publication year - 2006
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.23643
Subject(s) - differential scanning calorimetry , morphology (biology) , emulsion polymerization , polymer , monomer , chemical engineering , polymerization , pulmonary surfactant , polymer chemistry , phase (matter) , copolymer , emulsion , transmission electron microscopy , materials science , scanning electron microscope , chemistry , nanotechnology , composite material , organic chemistry , thermodynamics , physics , biology , engineering , genetics
We performed a series of experiments to study the effect of a chain transfer agent, n ‐dodecyl mercaptan ( n ‐DM), on the development of morphology in composite latex particles. The morphologies were determined using a combination of transmission electron microscopy, differential scanning calorimetry, and surfactant titration. The polymer molecular weights were reduced up to 10‐fold with n ‐DM levels up to 1.4% in the monomer. The addition of n ‐DM can increase the extent to which second‐stage polymer domains are formed within the interior regions of the seed particles, but this is only expected under specific conditions. Numerical simulations support this conclusion. We also observed that the reduction in the molecular weight of the second‐stage polymer did not significantly increase the extent of phase separation and morphology rearrangement within the particles. The overall effect on the morphology was limited. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 945–957, 2006