Oligomères amphiphiles obtenus par voie radicalaire, 3. Simulation et contrôle de la synthèse d'oligomères de i'acide acrylique et de i'acrylamide à extrémité thio

The synthesis of amphiphilic oligomers through radical initiated polymerization of hydrophilic monomers in the presence of long hydrocarbon chain thiols as transfer agents was simulated using a model based on a kinetic scheme similar to that proposed by Ikada. Taking into account the solvent as a secondary transfer agent, the weight fractions of different oligomer molecules and the average degrees of polymerization versus conversion were determined as a function of the mole ratio [thiol]/[monomer] and the solvent transfer constant. A relatively good agreement was found between the theoretical and the experimental values for acrylic acid (AA) and acrylamide (Am) oligomerizations. Oligomers terminated by the solvent could complete with thiol-terminated oligomers. It is interesting that by modifying the simulation model, it is possible to estimate the amount of thiol necessary to keep the composition of the reactant mixture constant during synthesis, thereby eliminating the drift in the oligomer composition at high conversion.