Terpolymerization of 3-methacryloxpropyl tris(trimethylsiloxy)silane, methacrylic acid and dimethyl octyl ammonium styrene sulfonate: determination of the reactivity ratios
G. Helary et al., Terpolymerization of 3-methacryloxpropyl tris(trimethylsiloxy)silane, methacrylic acid and dimethyl octyl ammonium styrene sulfonate: determination of the reactivity ratios, EUR POLYM J, 36(11), 2000, pp. 2365-2369
Terpolymerization of 3 methacryloxypropyl tris(trimethylsiloxy)silane (MPTS
), methacrylic acid (MA) and dimethyl octyl ammonium styrene sulfonate (DOA
SS) using azobis(isobutyronitrile) as initiator was carried out in dioxane
which is the common solvent of the three monomers, The reactivity ratios fo
r the three couples of monomers MPTS/MA, MPTS/DOASS and MA/DOASS were calcu
lated according to the general copolymerization equation using the Finneman
n-Ross, Kelen-Tudos and Tidwell-Mortimer methods. The values of the reactiv
ity ratios indicate that the different monomer units are randomly distribut
ed along the chains and the compositions of the different copolymers are ho
mogeneous. From the reactivity ratios and using the terpolymerization equat
ions, the average compositions of the comonomers in the terpolymers were ca
lculated. A good agreement between the experimental and theoretical composi
tions was observed which meant that the reactivity only depended on the ter
minal units for the free-radical species. The instantaneous compositions ar
e constant at a conversion less than 70%. For a higher conversion, the prob
ability of the formation of MPTS-MPTS-MPTS triads increases highly. (C) 200
0 Elsevier Science Ltd. All rights reserved.