Kinetic study on the poly(methyl methacrylate) seeded soapless emulsion polymerization of styrene. II. Kinetic model

Abstract

SYNOPSISA seeded soapless emulsion polymerization was carried out with poly(methy1 methacrylate) (PMMA) as seeds, styrene as monomers, and potassium persulfate (K2S2O8) as the initiator to synthesize the PMMA/polystyrene (PS) composite latex. The morphology of the latex particles was observed by transmission electron microscopy (TEM). It showed a core-shell structure. A core-shell kinetic model was proposed for the seeded emusion polymerization, in which the thickness of the shell was not constant. An increase of the conversion would increase the thickness of the shell. The entire course of polymerization could be divided into three regions: In the first region, the propagation rate constant (K,) and termination rate constant (K,) were kept constant at constant temperature. The kinetic data showed that the square root of polymer yield (Wi") was proportional to the reaction time. In the second region, the gel effect was considered and the termination rate constant (K,) was empirically modified. The K , would decrease with increasing the conversion. In the third region, both the gel effect and the glassy effect were considered the propagation rate constant was also empirically modified. The prediction on the conversion and the number-average molecular weight of polymers during the seeded emusion of polymerization on the basis of our core-shell kinetic model fitted well with the experimental data. 0 1995

Kinetic study on the poly(methyl methacrylate) seeded soapless emulsion polymerization of styrene. III. Seeds with crosslinking

“…The core-shell kinetics model that was of the styrene monomer. Substituting V r into R p , proposed in our previous work [2][3] described that we obtained the shell was the reaction zone; that is, the polymerization reaction took place only on the shell.…”

“…distributed in either core or shell region in the Assuming steady state for all radicals, polymer particle was saturated. Equation (7) could be rewritten as follows [2][3] :…”

“…They found that in was added to the seed latex and then polymerized the ABS latex, the SAN (acylonitrile-butadienewithout forming new particles. [2][3][4] There were styrene) microdomain distributed in the PB matrix. Flory and Stockmayer 13 pointed out the kinetic at the temperature of reaction.…”

The functional features and interface design of wood/polypropylene composites based on microencapsulated wood particles via adopting in situ emulsion polymerization

“…To construct initial microencapsulated environment, crosslinking agent was added half an hour early. Experimental time was fixed at 2 h . The selectivity of acrylates was based on its excellent stickiness and adhesive property, which have been illustrated as binding materials in polymer industry.…”

Synthesis of Fe3O4/PMMA composite latex particles: Kinetic modeling

“…In our previous work, Lee et al [15][16][17] synthesized the poly(methyl methacrylate)-polystyrene (PMMA/ PS) composite latex by the method of two-stage soapless emulsion polymerization. PMMA latex particles obtained from the first stage of polymerization acted as seeds, and the second stage of polymerization of styrene followed.…”