Styrene emulsification

Emulsification is the process by which a hydrophobic monomer, such as styrene, is dispersed into micelles and monomer droplets. A measure of a surfactant s abiUty to solubilize a monomer is its critical micelle concentration (CMC). Below the CMC the surfactant is dissolved ia the aqueous phase and does not serve to solubilize monomer. At and above the CMC the surfactant forms spherical micelles, usually 50 to 200 soap molecules per micelle. Many... 

For self-emulsification the molar mass of the EUP must be within a certain range. If the molar mass is too high, the solubility of the EUP is too low. If the molar mass is too low, the solubilizing efficiency is insufficient. With an EUP from maleic anhydride (MA) and hexanediol-1,6 (HD) and acid terminal groups, the optimal molar mass for the solubilization of a hydrophobic comonomer, such as styrene (S), was found to be between about 1700 and 2200 [116]. 

It appeared attractive to extend the work on emulsification of liquid-liquid systems by BG copolymers to solid-liquid systems. As a first approach a model system was studied which comprises titanium dioxide dispersed in toluene with modified styrene-butadiene block copolymers as dispersants. These studies are reported here. 

The membrane emulsification technique is also employed for the preparation of microspheres starting from monomers such as methacrylates (methylmethacrylate, cyclohexyl acrylate, etc.), polyimide prepolymer, styrene monomer [81], and so on. 

Emulsification and Emulsion Polymerization of Styrene Using Mixtures of Cationic Surfactant and Long Chain Fatty Alcohols or Alkanes as Emulsifiers... 

Influence of the Mixed Emulsifier Concentration. The stability of the miniemulsions increases with the concentration of the mixed emulsifier. Table III illustrates these results for the emulsification of two different oils styrene and silicon oil by liposarcosine chlorhydrate with a degree of polymerization of 2. 

The Table IV gives 2 examples of the influence of the method of emulsification on the stability of miniemulsions prepared with the same amounts of lipopeptide (LP) and cetyl alcohol (C15OH). When the oil is styrene the stability of the miniemulsion increases from 60 to 240 days. When the oil is vaseline oil, the stability of the miniemulsion increases from 20 to 70 days. 

Chou et al. observed that addition of relatively small amounts of styrene caused the rodlike crystals to disappear. They did not come to any condusion about the mechanism of tte emulsification process but suggested that the droplets may have been formed by diffusion of styrene into the crystalline, rodlike particles. 

Mathematical Treatment of the Emulsification of Benzene and Styrene in Aqueous Hexadecyltri-methylammonium Bromide-Cetyl Alcohol Mixtures... 

The mechanism of this mini-emulsion emulsification process was investigated by the conductometric titration of aqueous hexadecyltrimethylammonium bromide-cetyl alcohol mixtures with benzene or styrene combined with transmission electron microscopic examination of the morphology of the mixed emulsifiers and the styrene droplets formed (2,8). Figure 1 shows that the titration curves with and without cetyl alcohol are quite different that for... 

The recent successful synthesis in our laboratory of styrene-propylene diblock copolymer (iPS-fc-iPP), with crystalline isotactic structure in each block (20, 21), makes it possible to attempt toughening of the iPS-iPP blend by the method of block copolymer emulsification of the diblock copolymer. This... 

Other water-borne coatings include water-soluble emulsions, dispersions, and latex resins. Water-soluble resins are rare because most resins derived from vegetable oils are insoluble in water. The true emulsions are based on the emulsification of the oil or alkyd through either the action of a surfactant or a resin that has a surfactantlike character. The alkyd emulsions are readily prepared and can be used for OEM coatings and architectural applications. The submicron size droplets are stabilized by the thickeners (El-Aasser Sudol, 2004 Landfester, 2005 Landfester et al., 2004 Tsavalas et al., 2004 Weissenborn Motiejauskaite, 2000a,b). In dispersions, the resin is a solid and is dispersed in water. The latex resin is usually vinyl acetate, styrene, acrylates, or methacrylates radically copolymerized in a micelle to form particles 0.1 pm in diameter (Bloom et al., 2005 Brister et al., 2000 Jiratumnukul Van De Mark, 2000 Thames et al., 2005). 

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