Pickering emulsion polymerization kinetics of styrene: Comparison of bare and surface modified SiO2 nanoparticles
Por:
Fouconnier, B., Roman-Guerrero, A., Lopez-Serrano, F.
Publicada:
1 ene 2016
Resumen:
A step towards the understanding of some mechanistic events occurring in
the styrene Pickering emulsions, using a SiO2 dispersion, is presented.
Polymerizations at 80 degrees C with different levels of a water soluble
initiator were performed. The emulsion polymer content was ca. 15% with
conversions close to 90%. With conversion and particle size
measurements, the particle density was estimated for bare and surface
modified SiO2 particles. Then, the average number of radicals per
particle was inferred, yielding a pseudo-bulk type polymerization. It
was found that bare SiO2 nanoparticles do not participate in the
nucleation mechanism; however, they, along with the initiator, promote
an enhanced oligomer coagulation. On the other hand, the
hexadecyltrimethylammonium bromide modified SiO2 nanoparticles do
participate in the nucleation and coagulation mechanisms, yielding more
stable and smaller poorlycovered polymer particles. This approach
allowed untangling some events such as: particle nucleation, radical
entry to particles, particle density, coagulation and vitreous and
Trommsdorff effects.
Filiaciones:
Fouconnier, B.:
Univ Veracruzana, Fac Ciencias Quim, Xalapa, Veracruz, Mexico
Roman-Guerrero, A.:
Univ Autonoma Metropolitana Iztapalapa, Dept Biotecnol, Mexico City, DF, Mexico
Lopez-Serrano, F.:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Ingn Quim, Ciudad Univ, Mexico City 04510, DF, Mexico
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