Copolymer in emulsion polymerization

New Design for Producing Constant-Composition Copolymers in Emulsion Polymerization... 

Lee DY, Kim JH, Min TI. Role of alkali-soluble random copolymer in emulsion polymerization. Colloids Surf 1999 A153 89-97. 

Chem. Descrip. Sodium octoxynol-3 sulfate Uses Emulsifier for controlling particle size in vinyl acetate specialty copolymers, in emulsion polymerization, paints/coatings food-contact paper/paperboard... 

Guyot, A., Guillot, J., Pichot, C. and Guerrero, L. R. (1981) New design for producing constant-composition copolymers in emulsion polymerization comparison with other processes. Emulsion Polymers and Emulsion Polymerization (eds D.R. Bassett and A.E. Hamielec), ACS, Washington, pp. 415-436. 

In emulsion polymerization, NBR with acrylonitrile content between 15 and 50% can be obtained. The increase in the acrylonitrile content in the NBR produces an increase in the polar nature and solubility parameter in the copolymer [12]. Furthermore, the increase in acrylonitrile content improves the resistance to oils and also increases the glass transition temperature of the copolymers from -60 to-lO C. 

Utilization of another function of the macroinitiator was tried in emulsion polymerization [30]. An MAI composed of PEG (molecular weight of a segment is 1000) linked with AGP units was confirmed to be usable as a surface active initiator (Inisurf) for preparing PSt-b-PEG [30]. A higher molecular weight block copolymer was obtained in comparison with the case of solution copolymerization. 

Note This morphology is most commonly observed in copolymers or blends prepared in emulsion polymerization by the sequential addition and polymerization of two different monomer compositions. 

Polybutadiene, produced in emulsion polymerization, is not useful as an elastomer. However, the copolymers with styrene (SBR) and acrylonitrile (Buna-N) are widely used as elastomers. 

Such hydrophilic macromonomers (DPn=7-9) were radically homopolymer-ized and copolymerized with styrene [78] using AIBN as an initiator at 60 °C in deuterated DMSO in order to follow the kinetics directly by NMR analysis. The macromonomer was found to be less reactive than styrene (rM=0.9 for the macromonomer and rs=1.3 for styrene). Polymerization led to amphiphilic graft copolymers with a polystyrene backbone and poly(vinyl alcohol) branches. The hydrophilic macromonomer was also used in emulsion polymerization and copolymerized onto seed polystyrene particles in order to incorporate it at the interface. 

Paints. Paints (qv) prepared from poly(vinyl acetate) and its copolymers form flexible, durable films with good adhesion to dean surfaces, including wood, plaster, concrete, stone, brick, cinder blocks, asbestos board, asphalt, tar paper, wallboards, aluminum, and galvanized iron (147). Adherence is also good on painted surfaces if the surfaces are free from dirt, grease, and mst. Developments in emulsion polymerization for paint latices have been reviewed (148). 

In the industrial production of structured AN-Bu-St (ABS) latex particles, the grafting copolymerization of AN and St on crossUnked polybutadiene (PB) seed latex is carried out in emulsion polymerization. Therefore, information on the effect of PB crosslinking density on the swelling of PB latex particles by a St-AN monomer mixture is very important for the production of ABS copolymers with desired properties. Mathew et al. [177] studied the effect of several thermodynamic parameters, such as the crosslinking density, particle size and monomer mixture composition on the swelling behavior of PB latex particles by pure St and AN, and St-AN mixtures of various compositions. They reported... 

Emulsion polymerization has become an important process for the production of a large number of industrial polymers in the form of polymer colloids or latexes. They are the base of adhesives, paints and especially of waterborne coatings. An interest has been developed in recent years in emulsion polymerization systems in which the classical low molecular weight surfactaints are replaced by polymeric surfactants, either hydrophilic-hydrophobic block and graft copolymers (1-4) or functionalized oligomers (5). 

Figure 4.4 Some fluoropolymer derived materials used in SCCO2 technologies (a) copolymer used as stabilizer in emulsion polymerizations of styrene (b) end functionalized polymer used in metal extraction studies (c) a ligand used for homogeneous catalysis in SCCO2.

Aqueous dispersions of poly(vinyl acetate) and vinyl acetate-ethylene copolymers, homo- and copolymers of acrylic monomers, and styrene-butadiene copolymers are the most important types of polymer latexes today. Applications include paints, coatings, adhesives, paper manufacturing, leather manufacturing, textiles and other industries. In addition to emulsion polymerization, other aqueous free-radical polymerizations are applied on a large scale. In suspension polymerization a water-irnrniscible olefinic monomer is also polymerized. However, by contrast to emulsion polymerization a monomer-soluble initiator is employed, and usually no surfactant is added. Polymerization occurs in the monomer droplets, with kinetics similar to bulk polymerization. The particles obtained are much larger (>15 pm) than in emulsion polymerization, and they do not form stable latexes but precipitate during polymerization (Scheme 7.2). 

Urban D, Gerst M, Rossmanith P, Schuch H. Amphiphilic block copolymers as surfactants in emulsion polymerization. Polym Mat Sci Eng 1998 79 440-441. 

Rager T, Meyer WH, Wegner G, Mathauer K, Machtle W, Schrof W, Urban D. Block copolymer micelles as seed in emulsion polymerization. Macromol ChemPhys 1999 200 1681-1691. 

Muller H, Leube W, Tauer K, Forster S, Antonietti M. Polyelectrolyte block copolymers as effective stabilizers in emulsion polymerization. Macromolecules 1997 30 2288-2293. 

Bouix M, Gouzi J, Charleux B, Vairon JP, Guinot P. Synthesis of amphiphilic polyelectrolyte block copolymers using living radical polymerization. Application as stabilizers in emulsion polymerization. Macromol Rapid Commun 1998 19 209-213. 

A second possible problem with batch reactors is composition drift of copolymer systems. As with bulk, solution, and suspension systems, the more reactive monomer polymerizes first, and the least reactive polymerizes last. Two additional factors must be considered in emulsion polymerization. First, the water solubilities of the monomers can influence the course of the polymerization because of reaction in the water phase to produce copolymer oligomers or even water-soluble polymer. These molecules can be rich in the water-soluble monomer even if its reactivity is relatively low. Second, the high degree of subdivision achieved by producing small polymer particles can lead to phase domains that are smaller than those in copolymer produced by other processes. 

Other examples of peroxy inisurfs can also be found in Russian scientific papers. As for instance in Ref. [41] Voronov et al. describe a polymeric surfactant with peroxy side chains for application as inisurfs in emulsion polymerization. They obtained the polymeric inisurf (Inisurf 2) by copolymerization of a peroxide containing monomer (dimethyl-vinylethinyl-methyl-tm-butyl-peroxide) with acrylic or methacrylic acid or 2-methyl-5-vinyl pyridine with benzoyl peroxide as initiator in the presence of dodecylmercaptan as chain transfer agent. The resulting copolymers are water soluble at appropriate pH-values, surface active, and exhibit a critical micelle concentratioiL... 

The inisurfs can be used in emulsion polymerization without addition of surfactants to obtain, for example, butyl acrylate-styrene-copolymer dispersions with a solid content of about 35%. 

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