Polymerization in water

Solution polymerization of VDE in fluorinated and fluorochlorinated hydrocarbons such as CEC-113 and initiated with organic peroxides (99), especially bis(perfluoropropionyl) peroxide (100), has been claimed. Radiation-induced polymerization of VDE has also been investigated (101,102). Alkylboron compounds activated by oxygen initiate VDE polymerization in water or organic solvents (103,104). Microwave-stimulated, low pressure plasma polymerization of VDE gives polymer film that is <10 pm thick (105). Highly regular PVDE polymer with minimized defect stmcture was synthesized and claimed (106). Perdeuterated PVDE has also been prepared and described (107). 

Other reasons for a wide propagation of polymerization in water include (1) reduction of energy consumed to separate the initial monomer in crystal form (acrylamide is produced and used in the aqueous solution form), which, in addition, is associated with the probability of its spontaneous polymerization, and (2) recovery of the organic solvents, which results in less environmental pollution and the elimination of the stage of solution of polymer reagents used, as a rule, in the form of the aqueous solutions. 

Aluminum sulfate, A12(S04)3 H20, is the commonest alum used. Hydration is typically 14 to 16 H20. It hydrolyzes and polymerizes in water and typically is used within a narrow window of pH levels of 5.5 to 6.5 to minimize the solubility of aluminum in the treated water. If alkalinity is present (say, due to calcium bicarbonate), the following reaction occurs, producing insoluble aluminum hydroxide [Al(OH)3]. 

Copolymers of a cationic monomer and a vinyl alkoxysilane may be prepared by conventional vinyl polymerization techniques. These techniques include solution polymerization in water and emulsion polymerization with either free radical initiators or redox initiators. 

Polar organic compounds such as amino acids normally do not polymerize in water because of dipole-dipole interactions. However, polymerization of amino acids to peptides may occur on clay surfaces. For example, Degens and Metheja51 found kaolinite to serve as a catalyst for the polymerization of amino acids to peptides. In natural systems, Cu2+ is not very likely to exist in significant concentrations. However, Fe3+ may be present in the deep-well environment in sufficient amounts to enhance the adsorption of phenol, benzene, and related aromatics. Wastes from resinmanufacturing facilities, food-processing plants, pharmaceutical plants, and other types of chemical plants occasionally contain resin-like materials that may polymerize to form solids at deep-well-injection pressures and temperatures. 

Polymers Polyacrylamide and hydrolyzed polyacrylamide were prepared by the American Cyanamid Company specifically for this project, starting with l C labelled monomer. The radioactivity level of the monomer was kept below 0.20 mC /g in order to avoid significant spontaneous polymerization, utilizing a copper inhibitor. The homopolymer was synthesized by free radical solution polymerization in water at 40°C, using monomer recrystallized from chloroform, an ammonium persulfate-sodium metabisulfite catalyst system, and isopropanol as a chain transfer agent. Sodium... 

Copolymers of DMAEMA and AAm were prepared by free radical polymerization in water at room temperature using APS as initiator and TEMED as accelerator. The feed compositions for poly(DMAEMA-co-AAm) are shown in Table 1. The initiator and accelerator concentrations were 2 mg/mL... 

Oligomerization and polymerization of terminal alkynes may provide materials with interesting conductivity and (nonlinear) optical properties. Phenylacetylene and 4-ethynyltoluene were polymerized in water/methanol homogeneous solutions and in water/chloroform biphasic systems using [RhCl(CO)(TPPTS)2] and [IrCl(CO)(TPPTS)2] as catalysts [37], The complexes themselves were rather inefficient, however, the catalytic activity could be substantially increased by addition of MesNO in order to remove the carbonyl ligand from the coordination sphere of the metals. The polymers obtained had an average molecular mass of = 3150-16300. The rhodium catalyst worked at room temperature providing polymers with cis-transoid structure, while [IrCl(CO)(TPPTS)2] required 80 °C and led to the formation of frani -polymers. 

Working in emulsion is essentially limited to radical polymerization in water. Similar to suspension polymerization, the basic principle is to disperse a sparingly water-soluble monomer in water and bring about polymerization in this state. There are, however, some essential differences between the two procedures ... 

The study of template polymerization was preceded by examination of quaternary salts polymerization both in aqueous solution and in organic solvents. Examination of 4-vinylpyridine polymerization in water, induced by low molecular weight acids published by Salamone at al shows that in the first step, the following reaction occurs ... 

Recently, polymerization of sodium acrylate on polyallylamine hydrochloride template was described. In aqueous solution, sodium acrylate molecules are adsorbed onto a template with ammonium cationic pendant groups. The complex was polymerized in water solution using AIBN or K2S2O8 as initiators. Polymerization proceeds according to reaction ... 

Polyvinylpyrrolidone was also used for polymerization of maleic acid. Maleic acid can be polymerized in water in the presence of polyvinylpyrrolidone while the same monomer is very difficult to polymerize in the conventional manner. It was suggested by the authors that a product of polymer-polymer complex is formed with the following... 

D.M. Lynn, E.L. Dias, R.H. Grubbs, and B. Mohr, Acid activation of ruthenium metathesis catalysts and living ROMP metathesis polymerization in water, US Patent 6 486 279, assigned to California Institute of Technology (Pasadena, CA), November 26,2002. 

Manufacturing processes have been improved by use of on-line computer control and statistical process control leading to more uniform final products. Production methods now include inverse (water-in-oil) suspension polymerization or polymerization in water on moving belts. Conventional azo, peroxy, redox, and gamma-rav initiators are used in batch and continuous processes. 

Macromonomers afford a powerful means of designing a vast variety of well-defined graft copolymers. These species are particularly useful in the field of polymer blends as compatibilizers and/or stabilizers (surfactants). When macromonomer itself is an amphiphilic polymer, then its polymerization in water usually occurs rapidly as a result of organization into micelles. In copolymerizations, important factors for macromonomer reactivity are the thermodynamic repulsion or incompatibility between the macromonomer and the trunk polymer and its partitioning between the continuous phase and the polymer particles [4,5]. 

Comonomer l-vinyl-2-pyrrolidone (VP) comonomer can be purified by distillation at reduced pressure prior to use. Potassium persulfate (KPS) can be purified in a mixture of water and methanol. NIPAM-co-VP copolymers with different amounts of VP can be prepared at temperatures lower or higher than the LCST of PNIPAM by free radical polymerization in water with an initiator of KPS/N,N,N/,N/-tetramethylethylenediamine (TEMED) redox. The resultant copolymer can be harvested by precipitation, i.e., pouring the reaction mixture into an equal volume of methanol. Each resultant copolymer can be further purified by several cycles of re-dissolution in water and precipitation in methanol to ensure a complete removal of residual monomers. The final product can be dried under reduced pressure at 40 °C. 

The polyelectrolytes used in this study are displayed in Table 1. Hydrophobic flexible polyelectrolyte molecules of poly(methacryloyloxyethyl dimethylbenzylammonium chloride) (PMBQ) with a molecular weight of 4.2 Mio g/mol was synthesized by free radical polymerization in water solution as described elsewhere [18,19], Poly(so-dium styrenesulfonate) (PSS) with molecular weight of 70 000 g/mol was purchased from Aldrich and was used without further purification. Water purified and deionized (reverse osmosis followed by ion exchange and filtration) by means of Milli-RO 5Plus and Milli-Q Plus systems (Millipore GmbH, Germany) was used as a solvent. 

Thus, the butadiene polymerization in water medium initiated by the catalytic system KI + (C4H7NiX)2 (X = Cl, Br) is apparently effected by bis(7r-crotylnickel iodide). The reactivity and stereospecificity of the latter arise evidently from the stability of iodide bridges to hydrolysis. 

SEM investigations show that the morphology of the obtained particles depends on whether uncross-linked PVME and PVME microgels are used. In the case of uncross-linked PVME, small spherical particles in the range of 50-100 nm are formed. If Py is polymerized in water without any stabilizer (without PVME) the particles exhibit a cauliflower-like structure and the dispersion is unstable (Fig. 20a). 

Solution Polymerization. Plant scale polymerizations in water are conducted either adiabatically or isothemially. Molecular weight control, exotherm control, and reduction of residual monomer are factors which limit die types of initiators employed. Commercially available high molecular weight solution polyacrylamides are usually manufactured and sold at about 5% solids so diat die viscosities permit the dual product to be pumped easily. 

However, Plunkett s first reaction, and that of his technician, was one of frustration, because it would mean that they would have to start their experiment all over again. They didn t quite realize what they had But Plunkett was aware that the TFE had somehow polymerized. With 20/20 hindsight, given that Plunkett worked for a company that was at the forefront of polymer synthesis, he should have perhaps predicted that the polymerization of TFE was possible, if not likely. Frankly, Plunkett and Rebok were bloody lucky that they were not blown to bits Within a few weeks of laboratory testing, PTFE was found to be inert to all the solvents, acids and bases available. It was then quickly established by DuPont s polymer chemists that TFE could be free radically polymerized in water. Plunkett s discovery is legendary and for the 50th anniversary of the discovery of Teflon , DuPont established the Plunkett Award in his honor, for innovative applications of this unique material. 

The major commercial fluoropolymers are made by homopolymerization of tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE),vinyhdene fluoride (VF2), and vinyl fluoride (VF), or by co-polymerization of these monomers with hexafluoropropylene (HFP), perfluoro(propyl vinyl ether) (PPVE), per-fluoro(methyl vinyl ether) (PMVE), or ethylene. The polymers are formed by free-radical polymerization in water or fluorinated solvents. 

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