Emulsion polymerization layered double hydroxides

L. Z. Qiu and B. J. Qu, Preparation and characterization of surfactant-free polystyrene/layered double hydroxide exfoliated nanocomposite via soap-free emulsion polymerization. Journal of Colloid and Interface Science, 301 (2006), 347-51. 

Polymer-Layered Double Hydroxide Nanocomposites by Emulsion and Suspension Polymerization... 

Soap-free emulsion polymerization (SFEP) is an ideal method for the preparation of surfactant-free polymer-LDH nanocomposites. The mechanism of SFEP involves an in situ micellization model, where the oligomeric radicals generated by the free radical reaction of an ionic initiator and styrene monomer act as surfactants and assist in forming micelles. Therefore, no surfactants are used during the emulsion polymerization process. The SFEP method has been applied to the preparation of a surfactant-free polystyrene-layered double hydroxide exfoliated nanocomposite.In a typical synthesis, 0.05 g of MgAlNOs was dispersed in 80 ml of distilled water and sonolyzed for 30 min. The mixture was charged into a 150 ml four-necked reactor equipped with a baffle stirrer, a reflux condenser, a nitrogen inlet and a septum. The temperature of the reactor was raised to 70 °C and then 5 g of styrene and 20 g of aqueous potassium persulfate (KPS) solution (0.4 wt%) were added to the reactor as... 

Chapter 1 provides a brief overview on the synthesis of polymer nanocomposites in emulsion and suspension. Other synthetic methodologies such as in situ polymerization and melt intercalation are also described in comparison with emulsion and suspension polymerization. Chapter 2 describes the use of layered double hydroxides for the synthesis of nanocomposites in both emulsion and suspension. Properties and potential applications of such composites are considered. Chapter 3 describes nanocomposite synthesis in the inverse... 

The monomer solution makeup involves addition and solubilization of elemental sulfur and rosin (substituted diterpenes) in the chloroprene monomer. The water solution is made in a second vessel. Deionized water, sodium hydroxide, and a dispersant are mixed to form the water solution. The dispersant is a condensation product of naphthalene-sulfonic acid and formaldehyde. The monomer and water solutions are mixed with centrifiigal pumps to form an oil-in-water emulsion. The emulsion formed by virtue of formation of the sodiiun salt of rosin and resin components (abietic and dehydroabietic acids) having hydrophobic and hydrophilic ends. The large carbon-bearing portion of sodium abietate is hydrophobic and thereby solubilizes the monomer. The sodium carboxylate portion of sodium abietate is the hydrophilic end that extends into the aqueous phase and forms the electronic double layer that is critical to emulsion stability (84,85). In the patent example, the emulsion was added to the reactor and the temperatiu-e was increased to 40°C polymerization temperatiu-e (Table 3). 

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