Features of emulsion polymerization of styrene USAing slightly soluble initiators

Characteristic features of heterophase polymerisation of styrene with simultaneous formation of surfactants at the interface

“…It follows from the data given in Table 5 that the polymerisation rate w p somewhat increases as the alkyl radical of the The molecular mass (MM), equal to (2.5 ± 4.2)610 6 , and the molecular-mass distribution (MMD) of the polymers correspond to known published data on the emulsion polymerisation of styrene initiated by an oil-soluble initiator, namely, azobis(isobutyronitrile) 39 (Fig. 6).…”

“…The presence of the lower-molecular-mass peak is due to the fact that polymerisation occurs both in the bulk PMP and in the emulsifier micelles. 13,39 As noted above, an increase in the length of the alkyl radical is accompanied by a decrease in the solubility of its salts in the aqueous phase. Whereas potassium laurate, myristate, palmitate, and stearate are soluble in water fairly readily (30 mass % ± 70 mass %), potassium cerotate and behenoate are much less soluble (3 mass % ± 5 mass %).…”

“…Research into the synthesis of polymer dispersions with a specified diameter of particles and a narrow particle size distribution has shown that these properties are mainly dictated by the granulometric composition of the initial emulsion of the monomer, the time of formation of the PMP, and the creation of conditions which ensure stability of emulsions in the interfacial layer. 38,39 These factors depend on many parameters, most of all, on the conditions chosen for the preparation of emulsions and for polymerisation.…”

Mechanism of Soap-Free Emulsion Polymerization of Styrene and 4-Vinylpyridine: Characteristics of Reaction in the Monomer Phase, Aqueous Phase, and Their Interface

“…In this paper, the oil-soluble initiators, AIBN and BPO, were used, and the quasi-static emulsion polymerization was performed for 8 h. Although the minidroplet-like monomer layer was observed to settle down from the interface, the reaction in the aqueous phase and the particles formed nearby the interface were not found. This result indicates that the reaction in the aqueous phase hardly takes place due to the extremely low concentration of AIBN and BPO (the solubility in water, 50 °C: AIBN, 0.036 g/100 g; BPO: 0.001 g/100 g water). , Moreover, the decomposition rates may be too low to initiate the polymerization in the minidroplets of monomer before they returned to the monomer phase (70 °C, in styrene, k d (s -1 ) of AIBN and BPO is on the order of 10 -5 )…”

Factors influencing the preparation of hollow polymer-graphene oxide microcapsules via Pickering miniemulsion polymerization

“…In the case of miniemulsion polymerization using oil-soluble initiators, a significant fraction of initiation events are believed to result from (i) initiator located in the aqueous phase (partitioning), and (ii) initiator decomposition within a droplet followed by exit of one radical (and possible re-entry of the exited radical into another droplet) [57,58]. The aqueous phase solubility of AIBN is > 300 times greater than that of LPO [59] (0.36 g L À1 as opposed to 0.001 g L À1 at 20 C), and the presence of GO nanosheets at the droplet/particle interface is likely to markedly reduce the rate of entry/exit, which may lead to a reduced rate of initiation from AIBN-derived radicals. Due to partitioning on the basis of solubility, LPO is essentially confined to the droplet interior, resulting in a greater reaction rate due to higher local monomer concentration.…”