Ammonium persulfate phase

Polymerization of butyl acrylate was also studied by us in ethyl acetate/water two phase systems (3) using potassium persulfate/quaternary ammonium salts as the initiator system. Under these conditions (a minimum amount of water was used to dissolve the persulfate), it was found that symmetrical quat salts were more efficient than surfactant type quat salts. Also, the more lipophilic quat salts were more efficient. These results prompted us to propose formation of an organic-soluble quaternary ammonium persulfate via typical phase transfer processes. 

Until recently, the most detailed kinetic investigations of phase transfer free radical polymerizations were those of Jayakrishnan and Shah (11, 12). Both of these studies have been conducted in two phase aqueous/organic solvent mixtures with either potassium or ammonium persulfate as the initiator, and have corroborated our earlier conclusions (2, 3)... 

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). 

The sample used to study the relationship between the volume phase transition and the frictional property is poly( /V-isopropylacrylamide) gel which shows a small discontinuous volume phase transition at 33.6 °C. The sample gel is prepared by free radical polymerization 7.8 g of re-crystallized N-iso-propylacrylamide (main constituent, Kodak), 0.133 g lV,iV -methylenebis-acrylamide (cross-linker, Bio-Rad), 240 ml tetramethylenediamine (accelerator, Bio-Rad), and 40 mg ammonium persulfate (initiator, Mallinckrodt) are dissolved in distilled water (100 ml) at 0°C. The gel mold is immersed in the pre-gel solution and then degassed for 40 min at 0°C. The temperature is raised to 20.0 °C after this treatment to initiate the gelation reaction. The sample gel thus obtained is homogeneous and transparent, at least by visual inspection. 

Oxidation of arenes (8, 80-81). This oxidation can be carried out in a two-phase system with sodium dodecyl sulfate as a micellar catalyst. CAS can be used in catalytic amounts if ammonium persulfate is used in excess to convert Ce(lll) as formed to Ce(lV). This oxidation is slow in the absence of a Ag(l) salt. This catalytic two-phase oxidation is very useful for preparation of polycyclic quinones from hydrocarbons, but is ineffective for other substrates. 

Fig. 4, Electron micrograplis of latex particles obtained by potyniaization of (1) styrene (2) methyl methacrylate aud (3) methyl acrylate, SDDS, 0.066% ammonium persulfate, 0.05% in aqueous phase 7 80 0 phase ratio, 1 10,...

Fig. 7. Dependence of conversion %) over 30 min on sodium Blkylsutfonate concentration in potymenzation of (l) methyl acrylate end (2) butyl metliacTylBte. Ammonium persulfate, 0j0I% (l) and 0.1% (2) in aqueous phase T, 60 C phase ratio, I i.5.

Yeliseyeva et ai. (1976) studied the polymerization kinetics of polar acrylic monomers using ethyl acrylate. The dependence of the polymerization rate on the initiator concentration (ammonium persulfate) was examined at equal ionic strength in the presence of two emulsifiers, sodium dodecylsuDate and oxyethylaled (30) cetyl alcohol- Polymerization was carried out hi a dilatometer at 4S C, monomer-water phase ratio 1 9, and ammonium persulfate concentration 0.44-4.4 x 10 mol/dm. The obtained loagrithinic dependence is shown in Fig. 16. In each cases the... 

Fie, 21. Dependence of overall surface of particles ( ) on conversion during polymerization of ethyl acrylate. SDDS 1.04 xiO mcj/dm ammonium persulfate 0.44 X 10 moVdm phase ratio, 1 9 i 45°C. 

O Neill and Stannett (1974) also found, with sodium lautyl sulfiite as the emulsifier, that when a separate monomer (Aiase was present a milky slurry that was 100% filterable was formed even at low conversions. However, in the water-soluble region low solid latices were obtained. The initial rates were much higher than in the absence of emulsifiers as was previously reported by Karpov et al- A plot of tbe initial rates versus tbe monomer concentration is shown in Fig. 5. A first-order dependence on monomer concentration was found. Again, as with Karpov et al., considerable useful data is presented for systems where a separate monomer phase is present. Since these are not truly emulsion polymerizations, further details will not be discussed in this chapter. The molecular weights were essentially independent of the emulsifier concentration and in the same range, about 10 as found by Karpov et id. Izumi et al. (1967 Izumi, 1967) obtained similar results with ammonium persulfate as the initiator. 

The chemical polymerization of aniline at the interface between two immiscible solvents provides an attractive alternative route to PAn s. Such interfacial polymerization was first demonstrated in 1994 by Michaelson and McEvoy,82 who produced a freestanding PAn film at the interface between a solution of aniline/sodium dodecylsulfate in carbon tetrachloride and an aqueous oxidant solution containing ammonium persulfate/HCl. The analogous interfacial polymerization of a range of /V-alkylanilincs and o-alkylanilines using hexane and water phases for chemical oxidation with ammonium persulfate has also been briefly described.83... 

The kinetics of the homopolymerization of methyl methacrylate in the continuous phase of AOT reverse micelles was studied by Vaskova et al. [35]. Strong turbidity was observed in the course of polymerization, although MMA was highly diluted with toluene (Cmma—6%). The MMA polymerization in AOTsystem was compared to that in pure toluene and to that in toluene in the presence of AOT. Avery low polymerization rate was found with water-soluble ammonium persulfate. This indicates that only a small amount of MMA is present in the AOT water pools and that the APS radicals remain trapped inside. 

The in situ polymerization of aniline to form an electrically conductive textile was also first reported by Kuhn and coworkers [78,79] in which the polyaniline was deposited onto a textile substrate from an aqueous solution containing aniline, ammonium persulfate, hydrochloric acid, and either the disodium salt of 2,6-naphthalenedisulfonic acid or 1,3-benzenedisulfonic acid. In these studies, the polymerization conditions were controlled in order to deposit the polyaniline layer only onto the textile support with no polymer precipitating in the bulk liquid phase. This was accomplished by using dilute solutions of aniline (0.03 M). A subsequent study by Tzou and Gregory [92] on the deposition of polyaniline to nylon-6 fibers was focused on investigating the reaction kinetics of the chemically oxidative polymerization of aniline... 

Organic nanocomposite dispersions of PANI-SWNT are prepared by in situ synthesis of polyaniline as shown in Scheme - 3. Ammonium persulfate is added to aqueous phase and aniline in xylene is added from the top. After rigorous stirring, the system is then left idle, during which phase inversion occurs. No traces of SWNT were observed in the aqueous phase. The nanocomposite dispersion is then taken from the top and washed with excess amount of xylene. The filtered material is then dried imder dynamic vacuum at 60 °C for more than 24 hours. 

Oxidative polymerization in either solution or vapor phase Polymerization on colloidal cerium oxide particles In the presence of ammonium persulfate (oxidant) and dodecylbenzene sulfonic acid (dopant)... 

Ruckenstein and Sun [89] have used inverted emulsion polymerisation for the synthesis of PANI rubber composites using an isooctane-toluene mixture and water to form the emulsion and using ammonium persulfate as the oxidant. Inverse emulsion polymerisation consists of an aqueous solution of the monomer, which is emulsified in a non-polar organic solvent and the polymerisation is initiated with an oil-soluble initiator. The reaction is carried out in a heterogeneous system in which the reaction takes place in a large number of reaction loci dispersed in a continuous external phase. 

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