Seeded emulsion polymerization of styrene

Sheu and coworkers [111] produced polysty-rene-polydivinylbenzene latex interpenetrating polymer networks by the seeded emulsion polymerization of styrene-divinylbenzene in the crosslinked uniform polystyrene particles. In this study, a series of uniform polystyrene latexes with different sizes between 0.6 and 8.1... 

In another study, uniform composite polymethyl-methacrylate/polystyrene (PMMA/PS) composite particles in the size range of 1-10 fim were prepared by the seeded emulsion polymerization of styrene [121]. The PMMA seed particles were initially prepared by the dispersion polymerization of MMA by using AIBN as the initiator. In this polymerization, poly(7V-vinyl pyrolli-done) and methyl tricaprylyl ammonium chloride were used as the stabilizer and the costabilizer, respectively, in the methanol medium. Seed particles were swollen with styrene monomer in a medium comprised of seed particles, styrene, water, poly(7V-vinyl pyrollidone), Polywet KX-3 and aeorosol MA emulsifiers, sodium bicarbonate, hydroquinone inhibitor, and azobis(2-methylbu-... 

We now report on some experiments using seeded emulsion polymerization of styrene in which conditions were carefully chosen to ensure that Smith-Ewart Case 2 kinetics (6) would obtain throughout, in the absence of chain transfer/radical desorption effects. Various hydrocarbons were investigated for their effects on kinetics of polymerization and equilibrium swelling of the latex particles. 

Effect of Additives on the Rate of Seeded Emulsion Polymerization of Styrene... 

Figure 1 gives the conversion-time curves for the seeded emulsion polymerization of styrene in the absence and presence of various low molecular weight additives. Table I summarizes the results given in Figure 1. The rates of polymerization were determined from the straight line portion of the conversion-time curves (below 40% conversion) by least squares analysis of the experimental points. Table I also gives the calculated rates assuming a mere dilution of the monomer in the seed by the additive. It is clear that in every case the rate of polymerization is retarded much more than that due to dilution alone.

Figure 1. Effect of addition of low molecular weight hydrocarbons as additives upon the progress of the seeded emulsion polymerization of styrene at 50°C.

Kinetics of the Seeded Emulsion Polymerization of Styrene in the Presence of Ethylbenzene, at 30°C... 

Nomura et al. [285] and Lichti et al. [286] studied the effects of transfer agents on the kinetics of ab initio and seeded emulsion polymerization of styrene, respectively. Nomura et al. found that the polymerization rate per particle decreased with increasing amounts of carbon tetrachloride, carbon tetrabromide and primary mercaptans, and that the effects were stronger when... 

Fig. 11. Conversion versus time curves for seeded emulsion polymerizations of styrene with hexadecane present in the monomer phase. T — 333 K.

Figure 5.14 The slope of the straight-line region of the instantaneous number MMD for 44 and 130 nm radii seeded emulsion polymerizations of styrene at 30 °C (one example of which is shown in Figure 5.12) rec culated from data in [57], The slope is plotted as A = —AfodlnP(A/)/

Yang et al. [27], using small-angle neutron scattering (SANS), reported the formation of supermolecular structures in polystyrene latex particles prepared by the seeded emulsion polymerization of styrene onto deuterated polystyrene particles. The recorded scattering intensities, which were much higher than those expected on the basis of the Debye random coil model, indicate the presence... 

S. W. Prescott, M. J. Ballard, E. Rizzardo, R. G. Gilbert, Successful use of RAFT techniques in seeded emulsion polymerization of styrene living character, RAFT agent transport and rate of polymerization. Macromolecules 2002, 35, 5417-5425. 

No.26,18th Dec. 2001, p.8907-12 EFFECT OF A REACTIVE SURFACTANT AND ITS POLYMERIC COUNTERPART ON THE KINETICS OF SEEDED EMULSION POLYMERIZATION OF STYRENE Wang X Boya B Sudol E D El-Aasser M S Lehigh University... 

Interval III Particle Growth in the Absence of Monomer Droplets.—James and Sundberg have published the results of an experimental study of ideal and non-ideal behaviour in the seeded emulsion polymerization of styrene. Unlike the experiments on seeded emulsion polymerization reported in papers referred to above, the amounts of monomer added to the seed latices were less than those required to saturate the particles and form a separate monomer droplet phase. The reaction systems were therefore the seed analogues of Interval III of a conventional emulsion polymerization reaction. The results are found to be in good agreement with the predictions of the Stockmayer-O Toole theory, provided that allowance is made for the effect of monomer/polymer ratio at the reaction locus upon the rate coefficient for bimolecular mutual termination. A paper by Hamielec and Marten is concerned with the effects of chain entanglements and the rubber-glass transition... 

Bartsch S. Kulicke WM, Fresen I, Moritz HU. Seeded emulsion polymerization of styrene determination of the particle size by flow field-flow fractionation coupled with multi-angle laser light scattering. Acta Polym 1999 50 373-380. 

It is noteworthy that a basic assumption made in the derivation of the free radical desorption rate constant is that the adsorbed layer of surfactant or stabilizer surrounding the particle does not act as a barrier against the molecular diffusion of free radicals out of the particle. Nevertheless, a significant reduction (one order of magnitude) in the free radical desorption rate constant can happen in the emulsion polymerization of styrene stabilized by a polymeric surfactant [42]. This can be attributed to the steric barrier established by the adsorbed polymeric surfactant molecules on the particle surface, which retards the desorption of free radicals out of the particle. Coen et al. [70] studied the reaction kinetics of the seeded emulsion polymerization of styrene. The polystyrene seed latex particles were stabilized by the anionic random copolymer of styrene and acrylic acid. For reference, the polystyrene seed latex particles stabilized by a conventional anionic surfactant were also included in this study. The electrosteric effect of the latex particle surface layer containing the polyelectrolyte is the greatly reduced rate of desorption of free radicals out of the particle as compared to the counterpart associated with a simple... 

Slawinski, M., Meuldijk, J., Van Herk, A.M., and German, A.L. 2000. Seeded emulsion polymerization of styrene Incorporation of acrylic acid in latex products. J. Appl. Polym. Sci. IS 875-85. 

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