Polystyrene emulsions

Because of this interaction, PVP has found appHcation in surfactant formulations, where it functions as a steric stabilizer for example to generate uniform particle-size polystyrene emulsions (110—112). In a variety of formulations, a surfactant s abiHty to emulsify is augmented by PVP s abiHty to stabilize coUoids stericaHy and to control rheology. 

Emulsion Polymerisation It is a very good process which is used for the preparation of polystyrene. Emulsion polymerisation which is mainly used in the production of polystyrene latex used in water-based surface coating. 

Since it was observed that a 50% increase in surfactant was required to prepare a coagulate-free polystyrene emulsion compared with poly-(methyl methacrylate) emulsion, it appears clear that for poly-S emulsion Equation 1 is shifted to the right compared with poly-MMA emulsion. 

It has been shown that the stability of colloidal suspensions can also be influenced by a pure alcohol-water mixture, without the addition of any surface active agent. In a study of the flocculation of polystyrene emulsions in ethanol-water mixtures (42), the concentration of sodium chloride required to produce rapid flocculation increases with increasing ethanol concentration up to 0.09 molar fraction, beyond this composition, the concentration of sodium chloride required for flocculation decreases rapidly. It will be very informative, therefore, to compare our coagulation rate obtained in the microemulsion media to that in pure IPA + water mixture. The results can be used to further delineate the role of inverted micellar structure on the enhancement of coagulation. 

By using modified colloidal particles as templates, silicon oxide macroporous materials with uniform submicrometer-sized pores can be synthesized.[14] Modified polystyrene emulsion microspheres (200 1000 nm) can be electronegative (sulfates) or electropositive (amidines). After these microspheres are packed in an orderly fashion, they can interact with surfactants and silicon oxides to form macroporous solid composites, and further to form macroporous materials after the removal of the templates by calcination. The sizes of the macropores in the products range from 150 to 1000 nm. Macroporous Ti02 can also be prepared in a similar way. 

A number of model in situ and on-site apphcations of low resolution, and therefore low cost, Raman spectroscopy have been reported including the quantitative monitoring of synthetic rubber and polystyrene emulsion polymerisations, detection of illicit drugs and explosives and detection of cyanide in wastewater using a surface enhanced Raman system [26]. 

It was demonstrated that particle size and concentration are parameters to which this technique is sensitive. Clearly, with suitable calibration techniques these techniques can be used in industrial reactors and processes as an example, of the differences found a batch reaction, Figure 24 shows the initial and final spectra obtained through a seeded polystyrene emulsion reaction. Note the dramatic changes in the reflectance spectra. 

Powders used for fluidized-bed painting [248, 249] include low- and high-pressure polyethylene, polyvinyl butyral (Butvar), polystyrene emulsion, polyamide resin type AK-7, polyoxymethyl-ene, polyvinyl chloride, a copolymer of styrene with methylmeta-crylate, epoxy resin type E-41, phenolformaldehyde resin No. 108, In addition to the main components, pigments and dyes imparting heat resistance and other qualities to the coating are introduced. 

Fig. IX.5. Amount of adhering developer powder as a function of the potential of the latent image (carrier pearl copolymer SNP-15). 1) Developer polystyrene emulsion with orange dye PS-5 2) with dark red PS-4 3) with violet PS-6.

Y. Fu, Z. Jin, Z. Liu, Y. Liu, and W. Li, Self-assembly of colloidal crystals from polystyrene emulsion at elevated temperature by dip-drawing method. Mater. Lett, 62, 4286-4289 [2008],... 

It is suggested to replace the NaCl solution with an aqueous AICI3 solution having a concentration of 10 M (mol L ). Assume that the electrophoretic mobility of the particles in the new solution is the same as previously, i.e. as calculated in question 1. Do you expect an improvement in the stability of the aqueous polystyrene emulsion Why/why not Justify your answer. 

---