Solution polymerization polymerization

Solution Polymerization. Solution polymerization is widely used ia the acryhc fiber iadustry. The reactioa is carried out ia a homogeaeous medium by usiag a solveat for the polymer. Suitable solveats can be highly polar organic compounds or inorganic aqueous salt solutions. 

Solution Polymerization. Solution polymerization of vinyl acetate is carried out mainly as an intermediate step to the manufacture of poly(vinyl alcohol). A small amount of solution-polymerized vinyl acetate is prepared for the merchant market. When solution polymerization is carried out, the solvent acts as a chain-transfer agent, and depending on its transfer constant, has an effect on the molecular weight of the product. The rate of polymerization is also affected by the solvent but not in the same way as the degree of polymerization. The reactivity of the solvent-derived radical plays an important part. Chain-transfer constants for solvents in vinyl acetate polymerizations have been tabulated (13). Continuous solution polymers of poly(vinyl acetate) in tubular reactors have been prepared at high yield and throughput (73,74). 

In contrast to bulk polymerization, solution polymerization provided soluble polymers with high molecular weights using low FeCl3 concentration at 120-140 C.31 A major disadvantage of the above approaches is that all the metal-halide catalysts need to be removed, since the catalyst residue will deteriorate die thermal stability and electrical and other properties. 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

Blending vegetable oils Blending gasoline Clay dispersion Fermentation (pharmaceutical) Suspension polymerization Emulsion polymerization Solution polymerization... 

Solution polymerization. Solution polymerization involves polymerization of a monomer in a solvent in which both the monomer (reactant) and polymer (product) are soluble. Monomers are polymerized in a solution that can be homogeneous or heterogeneous. Many free radical polymerizations are conducted in solution. Ionic polymerizations are almost exclusively solution processes along with many Ziegler-Natta polymerizations. Important water-soluble polymers that can be prepared in aqueous solution include poly(acrylic acid), polyacrylamide, poly(vinyl alcohol), and poly(iV-vinylpyrrolidinone). Poly(methyl methacrylate), polystyrene, polybutadiene, poly(vinyl chloride), and poly(vinylidene fluoride) can be polymerized in organic solvents. 

Polymer processing can be of several types, including free radical, cationic, anionic, metal complex, or metal oxide catalyzed, as mentioned earlier [5], Polymers can be made by bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization techniques [5], The automotive chemist or design engineer working for an OEM should be aware of these various manufacturing processes, which polymers are made by which process, and what characteristics can be expected from the type of process. 

Solution Polymerization. Solution polymerization is over 45 years old, but only about 3% of the PVC produced in the United States is made this way. The solution process differs from the other processes already discussed in that a solvent is added to the polymerization system. The system may be heterogeneous, in which case the monomer is soluble but the polymer is insoluble. Examples are the use of hexane, butane, ethyl acetate, or cyclohexane as solvents. After addition of a peroxide initiator and heating to 40 C, the polymerization starts and polymer precipitates out of solution as formed. In homogeneous reactions, both monomer and polymer are soluble therein. Examples are the use of dibutyl phthalate and tetrahydrofuran as solvents. 

Gas-phase fluidized bed polymerization, solution polymerization, slurry polymerization, and polymerization in melt under high ethylene pressure... 

Ring opening polymerization of L-lactide is generally the most preferred route for preparing high-molecular-weight PLA due to the possibility of an accurate control of the process. Lactide polymerization can be carried out using melt polymerization, bulk polymerization, solution polymerization, and suspension... 

PMMA is produced by emulsion polymerization, solution polymerization, and bulk polymerization. Generally, radical initiation is used (including living polymerization methods), bnt anionic polymerization of PMMA can also be performed. PMMA prodnced by radical polymerization (all commercial PMMA) is atactic and completely amorphous. Free-radical polymerization is carried out using benzoyl peroxide as an initiator in the presence of AdV-dimethyl-p-tolnidine (Figure 1.12) [60]. 

Key words real-time fiber optic mid-IR monitoring, isobutylene, styrene, p-tert-butylstyrene, living polymerization, solution polymerization, suspension polymerization... 

The different polymerization classes discussed above can be implemented in several ways bulk polymerization, solution polymerization, gas-phase polymerization, slurry polymerization, suspension polymerization and emulsion polymerization. 

Polycondensation can be carried out by various polymerization techniques including melt polymerization, solution polymerization, interfacial polymerization, emulsion polymerization and solid-state polymerization. These polymerization processes will be summarized briefly in the following paragraphs. 

Solution Polymerization — Solution-polymerization relies on a solvent to dissolve the monomer, catalyst and co-catalysts reaction, the polymer is precipitated using an antisolvent (e.g., n-hexane, methanol). The polymer is then filtered and dried. 

Of far greater commercial value than that of simple bulk polymerizations, solution polymerizations employ a co-solvent to aid in minimizing reaction viscosity as well as controlling polymer molecular weight and architecture. Lower polyaciylates are, in general, soluble in aromatic hydrocarbons, esters, ketones, and chlorohydrocarbons. Solubihties in ahphatic hydrocarbons, ethers, and... 

Solution Polymerization. Solution polymerization is used by a few producers in the acrylic fiber industry. The reaction is carried out in a homogeneous medium by using a solvent for the polymer. Suitable solvents are aqueous NaSCN used by Acordis and dimethyl sulfoxide [67-68-5] (DMSO) used by Toray. The homogeneous solution polymerization of acrylonitrile follows the conventional kinetic scheme developed for vinyl monomers (27-29) (see Bulk and Solution Polymerizations Reactors). 

Polymer nanocomposites are synthesized by a variety of methods, which include in situ polymerization, solution polymerization, and melt intercalation. The route for nanocomposite synthesis suggested by Toyota researchers was also based on in situ monomer polymerization in the presence of filler. Subsequently, Giannelis and co-workers [28, 29]... 

Method of synthesis produced by emulsion polymerization, solution polymerization and bulk polymerization radical initiation is used (Including living polymerization methods), but anionic polymerization of MMA can also be performed ... 

Poly(vinyl acetate) polymerization is accomplished by conventional processes, e.g., solution, bulk, or emulsion polymerization. Solution polymerization is favored because the subsequent alcoholysis reaction requires solvent addition. The polymerization step determines the ultimate molecular weight of the PVOH. Catalyst concentration, temperature, and solvent control the degree of polymerization acetaldehyde is an effective chain-transfer agent. It is the agent commonly used. 

Solution Polymerization. Solution polymerizations are frequently used in research laboratories because high yields can be reached without facing the difficulties associated with the gel effect. The solvents that can be used to this end must solubilize the polymer formed and be inert toward free radicals—in particular, not induce transfer reactions. The initiator, like all other reagents, must be soluble in the reaction medium, which is thus homogeneous. At the end of the polymerization, the polymer is recovered by evaporation of the solvent or by precipitation in a nonsolvent. 

Solution Polymerization Solution polymerization is usually carried out in a continuous-flow reactor system because of low-solution viscosity. Monomer is mixed with organic solvent and the polymer produced dissolved completely in the medium. The product from the solution process is used as a solution itself or as an intermediate for other applications. Because the... 

These four mechanisms are common to all types of free-radical polymerizations, for example bulk, solution, suspension and emulsion. The difference between the processes is the environment. In bulk polymerization there exists only one phase, initially the monomer, then as polymerization progresses a solution of the polymer in its own monomer. Both polystyrene and poly(methyl methacrylate) are produced in large quantities by bulk polymerization. Solution polymerization is similar in that there is only one phase present, but in this case the monomer is diluted with a fully miscible solvent and the final polymer is in solution in the solvent. PolyacryHc acid, with the solvent being water, is produced by this technique. In suspension polymer-... 

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