Some peculiarities concerning the mechanism and the kinetic behaviour of the vinyl chloride emulsion polymerization are described. Seeded emulsion polymerizations in the presence of an adequate mixture of anionic and non‐ionic surfactants were carried out in order to avoid the micellar initiation. New kinetic parameters were determined from the experimental data as follows: (i) MSA, the minimum surface area of polymer seed particles necessary to capture all ion‐oligoradicals generated in aqueous phase at a given initiator concentration; (ii) MCCI, the maximum critical concentration of initiator per unit surface of polymer particle under which the formation of new polymer particles is avoided; (iii) PVR1, the polymer volume per active growing radical, necessary to be within the particle for 1 s. It was found that the average number of propagating radicals per particle, n, depends on the size of the polymer particle, as a resultant of entry and exit and then of the initiation and termination reactions. The practical consequences of the accurate control of the polymer particles growing during seeded emulsion polymerization of vinyl chloride were emphasized.
The dependence of the polymerization rate on the concentrations of monomer, surfactant and initiator and on temperature in the semicontinuous emulsion polymerization of vinyl chloride at subsaturation pressure was determined experimentally. A kinetic model for the continuous emulsion polymerization of vinyl chloride at subsaturation pressure, based on the equation of total material balance of vinyl chloride and the experimentally determined kinetic equation of polymerization, is established.
The decomposition rate of potassium persulfate (KPS) in aqueous solutions, in the presence of sodium dodecyl sulfate (SDS) and poly(vinyl chloride) latex (PVC) was studied. The dissolved SDS increases the decomposition rate constant (kd) while the SDS aggregation as micella and/or its adsorption on the polymer hydrophobic surface results in a decreasing kd. The emulsifier ‐ free surface of the polymer particles increases the decomposition rate. A reaction mechanism based on emulsifier ‐ emulsifier and emulsifier ‐ polymer hydrophobic interactions is put forward.
Decomposition of potassium persulfate in sodium dodecyl sulfate solutions (of concentrations under and above CMC) and in the presence of poly(vinyl chloride) and vinyl chloride was studied. The decomposition rate has a maximum close to the CMC value of the final solutions. On the basis of experimental data a hemolytic mechanism in which a radical derived from dodecyl sulfate participates is proposed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.