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Control of the anisotropic morphology of latex nanocomposites containing single montmorillonite clay particles prepared by conventional and reversible addition‐fragmentation chain transfer based emulsion polymerization
Author(s) -
Mballa Mballa Monique A,
Ali Syed I,
Heuts Johan PA,
van Herk Alex M
Publication year - 2012
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.4185
Subject(s) - chain transfer , raft , materials science , montmorillonite , emulsion polymerization , chemical engineering , polymerization , polymer chemistry , copolymer , reversible addition−fragmentation chain transfer polymerization , cationic polymerization , molar mass , polymer , nanocomposite , radical polymerization , nanotechnology , composite material , engineering
Single montmorillonite platelets have been successfully encapsulated by polymer through both a conventional and a reversible addition‐fragmentation chain transfer (RAFT) based emulsion polymerization. For both synthetic methods, the encapsulation process basically consisted of three steps: (i) adsorption of cationic RAFT copolymers (RAFT approach) or surfactant (conventional approach); (ii) high shear dispersion of the stabilized clay in aqueous solutions; (iii) starved‐feed addition of monomers starting the polymerization. In the conventional approach, the morphology of the latex/clay nanocomposites was close to the dumbbell shapes previously reported and did not depend on the presence of organic modifier as evidenced by cryotransmission electron microscopy and scanning electron microscopy. In the RAFT approach a completely different morphology was obtained which has been coined the cornflake morphology. With these two new approaches we can control the orientation of the clay platelets inside the latex particles which in turn can control the orientation of the clay platelets in a film. A perspective on possible applications of these different morphologies is given, e.g. their use in high barrier coatings. Copyright © 2012 Society of Chemical Industry