Potassium persulfate styrene

The polymerization reaction is conducted at the desired temperature with a slow stirring regime for a certain period. A typical recipe for the emulsion polymerization of styrene is exemplified in Table 1 [40]. As seen here, potassium persulfate and sodium dodecyl sulfate were used as the initiator and the stabilizer, respectively. This recipe provides uniform polystyrene particles 0.22 /Lim in size. 

Radical polymerization of styrene was carried out in the presence of bare silica particles, and of the HPC-coated silica particles in water by using potassium persulfate as an initiator. Table 2 gives the typical ingredients used for these polymerizations. The HPC-coated silica particles were prepared under the same conditions as in the adsorption experiments. The polymerization temperature was kept at 1+5 °C to protect the adsorption layer of HPC, and polymerized for 2l+ hrs in the same manner as that... 

In 1981 we reported (2, 3) the first examples of free radical polymerizations under phase transfer conditions. Utilizing potassium persulfate and a phase transfer catalyst (e.g. a crown ether or quaternary ammonium salt), we found the solution polymerization of acrylic monomers to be much more facile than when common organic-soluble initiators were used. Somewhat earlier, Voronkov and coworkers had reported (4) that the 1 2 potassium persulfate/18-crown-6 complex could be used to polymerize styrene and methyl methacrylate in methanol. These relatively inefficient polymerizations were apparently conducted under homogeneous conditions, although exact details were somewhat unclear. We subsequently described (5) the... 

Very recently, Ghosh and Mandal have reported (20) a thorough kinetic investigation of the polymerization of styrene in the two phase system water/o-dichiorobenzene using potassium persulfate as initiator and tetrabutylammoniurn bromide These studies were conducted at and pH, and found that the rate showed a square root dependence... 

The synthetic methods and chemical characterization data for the various polymeric materials to be discussed in this work have been reported elsewhere [6-8]. In some cases copolymerization of the unchlorinated oxazolidinone monomer with other common monomers such as acrylonitrile, vinyl chloride, styrene, and vinyl acetate, using potassium persulfate as an initiator, was performed. In other cases the unchlorinated oxazolidinone monomer was grafted onto polymers such as poly(acrylonitrile), poly(vinyl chloride), poly(styrene), poly(vinyl acetate), and poly(vinyl alcohol), again using potassium persulfate as an initiator. 

Add 128.2 g of distilled water, 71.2 g of styrene, 31.4 ml of 0.680% potassium persulfate, and 100 ml of 3.56% soap solution (see Note 1) to a three-neck round bottom flask equipped with a mechanical stirrer, condenser, and nitrogen inlet tube. 

The need for increased stabilities and for controllable permeabilities and morphologies led to the development of polymerized surfactant vesicles [55, 158-161]. Vesicle-forming surfactants haw been functionalized by vinyl, methacrylate, diacetylene, isocyano, and styrene groups in their hydrocarbon chains or headgroups. Accordingly, SUVs could be polymerized in their bilayers or across their headgroups. In the latter case, either the outer or both the outer and inner surfaces could be polymerized separately (Fig. 38). Photopolymerization links both surfaces selective polymerization of the external SUV surface is accomplished by the addition of a water-soluble initiator (potassium persulfate, for example) to the vesicle solution. 

Finally, the ASA graft copolymer is prepared. To the alkyl acrylate rubber polymer obtained as described just above, styrene and acrylonitrile are added in the desired quantities. Dodecylmercaptan and potassium persulfate are added as chain transfer agent and radical initiator, respectively. An ASA copolymer with a mean diameter of 550 nm is obtained. 

On the other hand, chemicals might be chosen as agents for generation of active centers in the polymeric backbone and grafting of monomer in the vapor phase. Ammonium persulfate and styrene (189), acrylic acid (190), butyl acrylate (191), potassium persulfate and n-butyl maleate or 2-ethyl hexyl acrylate (55,134) and ammonium ceric nitrate and methacrylic add (192) are examples of this method. Benzoyl peroxide deposited on polycaprolactam fibers initiates the grafting of styrene in vapor phase (193). 

N-(Hydroxymethyl)acrylamide (HMA, Tokyo Kasei Co.) was recrystallized from ethyl acetate. N,N-Dimethylacrylamide (DMA, Tokyo Kasei Co.) and styrene (St, Kashima Kagaku Yakuhin Co.) were distilled at 54°C/3.5 mmHg and 40°C/14.5 mmHg, respectively. In some copolymerizations cross-linking reagents were added to reduce the formation of water-soluble polymer. N -Methylenebisacrylamide (MBA, Nakarai Chemicals Co.) and N-allylacrylamide (AAA, Polysciences, Inc.) were used as received. Divinylbenzene (DVB, Tokyo Kasei Co.) was treated with 10 % sodium hydroxide and dried. Two kinds of initiators were used Potassium persulfate (KPS, Taisei Kagaku Co.) was recrystallized from water and azobis(isopropyl-... 

Terpolymer Resins. DBPF was dissolved in a mixture of styrene, acrylonitrile, and mercaptan (Table I). About one-tenth of this solution was added to a solution of sodium alkylbenzene sulfonate emulsifier (Nacconal NRSF, 2 parts) in deionized water (180 parts) at 60°C. Potassium persulfate (0.3 part) was added, followed by the remaining monomer mixture at a rate consistent with temperature control (60°C.) Gentle agitation and a nitrogen atmosphere were maintained throughout the polymerization. The latex was maintained at 60 °C. until a solids determination indicated no further conversion (6—8 hours total polymerization time). 

Graft Polymers. The procedure used was described by Cummings (3). To a quantity of commercially available polybutadiene latex (52.3% solids) containing 50 parts of rubber was added sufficient deionized water to increase the water content to 180 parts. The diluted latex was heated to 60°C. Potassium persulfate (0.3 part) and monomers (styrene, acrylonitrile, DBPF 50 parts) were added, and poly-... 

In the polymerization of styrene, using potassium persulfate as initiator. Roe ( ) observed that the total number of particles in latices depended on the composition of the mixed surfactants and not on the total number of micelles. Therefore, he devaluated the micellar nucleation mechanism for emulsion polymerization as proposed by Harkins( ) -Smith-Ewart(j). 

Although there are numerous references to the emulsion polymerization of vinyl ferrocene, they all appear to emanate from a single source (j4). These workers polymerized vinyl ferrocene alone, and with styrene, methyl methacrylate, and chloroprene. No characterization was reported other than elemental analysis. The molding temperatures reported (150 - 200 C) correspond to the Tg range indicated by Pittman ( ) for similar copolymers. The initiation system was preferably azobisisobutyronltrile, although potassium persulfate was also used. Organic peroxides were contraindicated, due to oxidation problems with the ferrocene moiety. 

Figure 1 shows the equipment used. The tubular reactor was 240 ft (73m) long, 0.5 inch (1.27cm) OD, Type 316 stainless steel. The reactor was placed in an agitated, constant temperature water bath. Two gear pumps were used to give metered flow of the two feed streams-an emulsion of styrene in an equal volume of water, and a solution of potassium persulfate in water. Table 1 shows the recipe used for polymerization. 

Maclay, W. N., The mechanism of extender action by potassium persulfate in suspension polymerization of styrene, J. Appl. Polym. Sci. 15, (1971) 867. 

Rabagliati et al. (14) studied the polymerization of styrene in a three phase system containing an anionic-nonionic surfactant mixture and brine. Both AIBN and potassium persulfate initiators were used. The system was reported to be microemulsion continuous and even multicontinuous. (14). No autoacceleration was observed and the authors concluded that the polymerization exhibits an inverse dependence of the degree of polymerization on initiator concentration, similar to bulk solution polymerization. 

Styrene (99% pure) was obtained from Fisher Scientific and Aldrich Chemicd. It was used either as supplied or after purification to remove the inhibitor. To remove the inhibitor, styrene (Aldrich) was washed three time with 10% sodium hydroxide and dried over phosphorus pentoxide in a desiccator after repeated washing with water. The purified sample was stored under nitrogen at 0<>C. Potassium persulfate and AIBN initiators were obtained from Fisher and DuPont, respectively, and were used without further purification. Sodium... 

Polymerization of the microemulsion systems was performed under nitrogen environment using both purified styrene and unpurified styrene containing inhibitor. The polymerization was initiated by the thermal decomposition of potassium persulfate or AIBN at 6Q0C. The polymerization duration for the purified styrene system under nitrogen environment was 18 hours, whereas it took 36 hours for the styrene with inhibitor. The mode and dynamics of polymerization were observed using both polarized light and enhanced video microscopy (22). 

Polymerization of styrene in each of the three types of microemulsions was performed using a water soluble initiator, potassium persulfate (K2S208), as well as an oil-soluble initiator, AIBN. As desired, solid polymeric materials were obtained instead of latex particles. In the anionic system, the cosolvent 2-pentanol or butyl cellosolve separates out during polymerization. Three phases are always obtmned after polymerization. The solid polymer was obtained in the middle with excess phases at the top and bottom. GC analysis of the upper phase indicates more than 80% 2-pentanol, while Karl-Fisher analysis indicated more than 94% water in the lower phase. Some of the initial microemulsion systems have either an excess organic phase on top or an excess water phase as the bottom layer. GC analysis showed the organic phase to be rich in 2-pentanol. However, the volume of the excess phase is much less in the initial system than in the polymerized system. 

The styrene (Polysciences) was washed with 10 aqueous sodium hydroxide to remove the inhibitor and vacuum-distilled under dry nitrogen the 1-pentanol (Fisher Scientific) was dried over potassium carbonate and vacuum-distilled the potassium persulfate (Fisher Scientific) was recrystallized twice from water the 2,2 -azobls(2-methyl butyro-nltrlle) (E. I. du Pont de Nemours) was recrystallized twice from methanol the sodium dodecyl sulfate (Henkel) was used as received its critical micelle concentration measured by surface tension was 5.2 mM. Dlstllled-delonlzed water was used in all experiments. 

Table I. Particle Size Distributions in Styrene Microemulsion Polymerization (0.55 mM potassium persulfate 70°C)...

Polymerization of styrene oll-ln-water mlcroemulslons using potassium persulfate or 2,2 -azobls(2-methyl butyronltrlle) initiator gave stable latexes which were bluish and less translucent than the original mlcroemulslons. The mechanism and kinetics of polymerization were... 

Figure 8. Conversion-time curves for 0.55 mM potassium persulfate with a consteint-volume oil phase of 1. 100/0 2. 75/25 3 50/50 styrene/toluene weight ratio.

In another interesting development, Yei et al. [124] prepared POSS-polystyrene/clay nanocomposites using an emulsion polymerization technique. The emulsion polymerization for both the virgin polystyrene and the nano composite started with stirring a suspension of clay in deionized water for 4h at room temperature. A solution of surfactant ammonium salt of cetylpyridinium chloride or POSS was added and the mixture was stirred for another 4 h. Potassium hydroxide and sodium dodecyl sulphate were added into the solution and the temperature was then raised to 50 °C. Styrene monomer and potassium persulfate were later on added slowly to the flask. Polymerization was performed at 50 °C for 8 h. After cooling, 2.5% aqueous aluminium sulphate was added to the polymerized emulsion, followed by dilute hydrochloric acid, with stirring. Finally, acetone was added to break down the emulsion completely. The polymer was washed several times with methanol and distilled water and then dried overnight in a vacuum oven at 80 °C. The obtained nanocomposite was reported to be exfoliated at up to a 3 wt % content of pristine clay relative to the amount of polystyrene. 

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