Ammonium persulfate as initiator

Grafting and networking may modify the mechanical, chemical, and functional properties of polymers and enhance their utilization for some purposes, such as for water treatment (Kumar and Verma, 2007 Mishra et al., 2003). Psyllium derivatives were prepared by grafting acrylonitrile onto psyllium molecules using a ceric ammonium nitrate and nitric acid system (Mishra et al., 2003). The resulted grafted psyllium samples were not soluble in commonly used solvents or their combinations. In 2007, methacrylic acid derivatives of psyllium were prepared using ammonium persulfate as initiator and cross-linked using N,N-methylenebisacryla-mide as the crosslinker (Kumar and Verma, 2007). The modified psyllium... 

The usual combination of components in the polymerisation mixture, and the only one for which we shall give experimental details comprises buffer salts acrylamide monomer, methylene N,N -bisacryl-amide (Bis), tetramethyl ethylenediamine (TEMED) as catalyst and ammonium persulfate as initiator. Variants are possible as mentioned in the previous chapter other catalysts may be used and also there may in some cases be advantages in eschewing the use of the persulfate, for example, when it is important to avoid too rapid setting of the gel in the course of more than usually complex... 

The polymerization is guided as a radical polymerization using dibenzoylperoxide, 2,2 -azobisisobutyronitrile or ammonium persulfate as initiator. The backbone can be modified by the reaction of 4-vinylpyTidine with benzyl chloride to get N-benzyl-4-vinylpyrid-ine monomers (41). 

Consider that a 10,000 L semibatch reactor must process vinyl acetate monomer with ammonium persulfate as initiator and sodium lauryl sulfate as a stabilizing agent, with the problem statement given in subsection 3,2 and the following values ... 

Polyacrylamide gel is the most commonly used type of support medium for gel electrophoresis, and polyacrylamide gel electrophoresis is simply known as PAGE. The gel is usually formed by polymerization of acrylamide and the cross-linking agent N, iV -methylene-bis-acrylamide (Bis) in the presence of ammonium persulfate (APS, initiator) and N, N, N, iV -tetramethyl-ethylenediamine (TEMED, accelerator). The total concentration of acrylamide... 

In this study, mechanical properties of emulsion copolymers of viityl acetate and butyl aciylate, which consisted of a nonionic emulsifier (30 mol ethoxylated nottyl-phenol), an oligomeric stabilizator, and ammonium persulfate or potassium persulfate as initiators by changing monomer ratios from 90 10 to 10 90 for VAc BuA, were determined by differential scanning calorimeter. 

Rasmussen and co-workers. Chapter 10, have shown that many free-radical polymerizations can be conducted in two-phase systems using potassium persulfate and either crown ethers or quaternary ammonium salts as initiators. When transferred to the organic phase persulfate performs far more efficiently as an initiator than conventional materials such as azobisisobutyronitrile or benzoyl peroxide. In vinyl polymerizations using PTC-persulfate initiation one can exercise precise control over reaction rates, even at low temperatures. Mechanistic aspects of these complicated systems have been worked out for this highly useful and economical method of initiation of free-radical polymerizations. 

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)... 

TABLE 1. Summary of random co-vinyl acetate derivatives prepared by emulsion polymerization using ammonium persulfate as the free radical initiator. 

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. 

Polyacrylamide gels with a total acrylamide content of 4-9 per cent T (in per cent) = [acrylamide -I- bismethylene acrylamide]/100) and C = 3-4 per cent (C = [bismethylene acrylamide]/r) are prepared in the standard way using ammonium persulfate as the initiator and tetramethylethylenediamine (TEMED) as the catalyst for gel formation (for general preparation of poly-... 

In many emulsion polymerization procedures, the original authors call for the use of ammonium persulfate as the water-soluble initiator. The shelf-life of this salt is quite limited and the concentration of available persulfate ions is quite variable from experiment to experiment. We therefore suggest, on the basis of our own experience, that either potassium persulfate or sodium persulfate be substituted for the initiation process, on a molar equivalent basis. Of these two latter salts, the sodium salt dissolves rapidly in water and usually may be added directly to the reaction flask. The potassium salt exhibits surprisingly low water-solubility. As a result, if potassium persulfate needs to be used, an aqueous solution of it should be prepared separately. Then this initiator solution is added to the emulsion polymerization system. 

Polyacrylonitrile, like PVC, is insoluble in its own monomer. Consequently, the polymer precipitates from the system during bulk polymerization. Aerylonitrile ean be polymerized in solution in water or dimethyl formamide (DMF) with ammonium persulfate as the initiator (redox initiation). The polyacrylonitrile homopolymer ean be dry spun from DMF direetly from the polymerization reactor or wet spun... 

The hydrogel membrane is a copolymer of N-isopropylacrylamide (NIPA) doped with methacrylic acid (MAA) and cross-linked with small amounts of ethylene glycol dimethacrylate (EGDMA). The prepolymer solution containing the monomers at the desired concentrations is poured between two glass plates separated by a 250 pm spacer. Polymerization is initiated using a combination of ammonium persulfate as free radical generator and tetraethylene-methylenediamine as accelerator. 

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. 

DADMAC 13C, for example, can be readily polymerized imder these cyclopolymerization conditions to yield PolyDADMAC in which a structure composed of 5-membered A -heterocycles predominates. 13C will readily polymerize at 35°C employing ammonium persulfate as the initiator. 13C is readily copolymerized with other diallyl monomers, with acrylamide monomers such as 28C or diacetone acrylamide, or quaternized 1C. Extensive reviews of cyclopol5mieriza-tion and cyclocopolymerization can be found in Reference 188. Recent examples of cyclocopolymerization with sulfobetaine (14C) and carboxybetaine (15C) diallyl ammonium monomers are given in References (188-191). 

Preparation 5-2 First, 1 mol acrylic acid and 0.3 mol Cetylstearyl+3EO+ 5PO methacrylate (Agnique DFM 250, Cognis GmbFF) are placed in a 250 ml polymerization flask at room temperature. The mixture is diluted with 58.6 ml water and set under nitrogen bubbling in order to remove all traces of oxygen. Then the mixture is heated to about 80°C and 1.4 ammonium persulfate as radical initiator is added. Since the polymerization is an exothermic reaction, the flask must be cooled in order to maintain a reaction temperature of 80-90° C. Once the polymerization is finished, the product is cooled to room temperature and treated with an aqueous sodium hydroxide solution to neutralize the acidic groups in the polymer and diluted with water to adjust a polymer content of 30%. 

Radical polymerization is done by N,NCmethylene bis acrylamide for crosslinking agent, ammonium persulfate as an initiator, N,N,N, N -tetramethylethylenediamide (TEMED) as an accelerator. Used in electrophoresis (2-chain DNA analysis)... 

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