Precipitation polymerization acrylic

The effect of the particle properties on the overall heat-transfer coefficient was investigated in our laboratory (43) for an acrylic precipitation polymerization as shown in Figure 6. 

In 1968, a French Patent issued to the Sumitomo Chemical Company disclosed the polymerization of several vinyl monomers in C02 [84], The United States version of this patent was issued in 1970, when Fukui and coworkers demonstrated the precipitation polymerization of several hydrocarbon monomers in liquid and supercritical C02 [85], As examples of this methodology, they demonstrated the preparation of the homopolymers PVC, PS, poly(acrylonitrile) (PAN), poly(acrylic acid) (PAA), and poly(vinyl acetate) (PVAc). In addition, they prepared the random copolymers PS-co-PMMA and PVC-co-PVAc. In 1986, the BASF Corporation was issued a Canadian Patent for the preparation of polymer powders through the precipitation polymerization of monomers in carbon dioxide at superatmospheric pressures [86], Monomers which were polymerized as examples in this patent included 2-hydroxyethylacrylate and iV-vinylcarboxamides such as iV-vinyl formamide and iV-vinyl pyrrolidone. 

Romack, T. J. Maury, E. E. DeSimone, J. M. Precipitation Polymerization of Acrylic Acid in Supercritical Carbon Dioxide. Macromolecules 1995, 28, 912. 

Copolymers Containing Carboxylic Groups. A new line of VP/acrylic acid copolymers in powdered form prepared by precipitation polymerization (147) from heptane have been introduced commercially (148). A wide variety of compositions and molecular weights are available, from... 

Different ionic monomers were copolymerized with NIPAAm or VCL to obtain pH- and temperature-sensitive microgels. Snowden et al. [65] reported preparation of aqueous microgels by copolymerization of NIPAAm and acrylic acid (AAc) in a precipitation polymerization process. The AAc content was 5wt%. Obtained microgels displayed pH and electrolyte sensitivity, as well as temperature sensitivity. 

The copolymerization of different functional monomers during precipitation polymerization can be used for design of amphoteric aqueous microgels [76-82], Amphoteric microgels were prepared by copolymerization of NIPAAm with acrylic acid and vinylimidazole (Vim) [76-80], Alternatively, Tan and coworkers prepared amphoteric colloids by copolymerization of acrylic acid, 2-(diethylamino)ethyl... 

Polycarbophils are synthetic, high-molecular-weight, cross-linked polymers of acrylic acid. These poly(acrylic acid) polymers are crosslinked with divinyl glycol. They are synthesized via precipitation polymerization in ethyl acetate and then dried. 

Liu, T. Desimone, J.M. Roberts, G.W. Continuous precipitation polymerization of acrylic acid in supercritical carbon dioxide The polymerization rate and the polymer molecular weight. J. Polym. Sci. A 2005, 43 (12), 2546-2555. 

C40-60 alcohols EPM rubber PPS resin mfg. p-Dichlorobenzene pre-/post-polymerization PEG-6 acrylate PEG-9 acrylate precipitant... 

Example 3.14a Free Radical Polymerization of Cyciodextrin Host-Guest Complexes of Butyl Acrylate from Homogeneous Aqueous Solution (Precipitation Polymerization)... 

POly(acryliC acid). Poly(acrylic acid) (PAA) can be prepared by direct tree-radical polymerization of 2 in aqueous solution (6) or by precipitation polymerization in benzene. Alcohols and mercaptans are commonly used chain-transfer agents for regulating polymer molecular weight. Alternatively, PAA can be prepared by hydrolysis of poly(alkyl acrylates) (6) (Fig. 29). 

Several general disadvantages of bulk polymerization (removal of the reaction heat, shrinkage, nonsolubility of the resulting polymer in the monomer, side reactions in highly viscous systems such as the Trommsdorff effect or chain transfer with polymer) are responsible for the fact that many polymerization processes are carried out in the presence of a solvent. A homogeneous polymerization occurs when both monomer and polymer are soluble in the solvent. When the polymer is insoluble in the solvent, the process is defined as solution precipitation polymerization. Other heterogeneous polymerization reactions in liquid-solid or liquid-liquid systems such as suspension or emulsion polymerizations are described later. Conventional solution polymerization is compared with solution precipitation polymerization for the synthesis of acrylic resins in Ref. [34]. 

It may be worth noting that just as in the case of acrylic emulsion polymerizations, ferrous sulfate has a catalytic effect on the polymerization of acrylic and methacrylic acids initiated by hydrogen peroxide. To prevent precipitation of ferric oxides, the system must be maintained at a very low pH [29]. 

TJ Romack, EE Maury, JM DeSimone. Precipitation polymerization of acrylic acid in supercritical carbon dioxide. Macromolecules 1995 28 912-915. 

The production of such particles usually results fi-om the emulsion copolymerization of a hydrophobic monomer, such as styrene with a water-soluble monomer, such as acrylic acid. Differences in water solubility of the two monomers along with disparate reactivity ratios led to the preparation of particles having a core-shell structure with the hydro-phobic polymer in the core and the water-soluble polymer in the shell layer. It was also found that precipitation polymerization of alkyl(meth)acrylamide, such as N-isopropyl... 

The most commonly used scale inhibitors are low molecular weight acrylate polymers and organophosphoms compounds (phosphonates). Both classes of materials function as threshold inhibitors however, the polymeric materials are more effective dispersants. Selection of a scale control agent depends on the precipitating species and its degree of supersaturation. The most effective scale control programs use both a precipitation inhibitor and a dispersant. In some cases this can be achieved with a single component (eg, polymers used to inhibit calcium phosphate at near neutral pH). 

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