Polystyrene latex preparation

Criticize or defend the following proposition Zeta potentials for three different polystyrene latex preparations were calculated by the Helmholtz-Smoluchowski equation from electrophoresis measurements made in different concentrations of KCl.f... 

Seven polystyrene latexes prepared with persulfate initiator and bicarbonate buffer were characterized to demonstrate the efficacy of this method (6). Three were monodisperse latexes prepared using conventional emulsifiers four were prepared using sodium styrene sulfonate or sodium vinyltoluene sulfonate as canan-omeric emulsifiers. Each latex was subjected to serum replacement with... 

The latexes investigated were the 357 nm Dow monodisperse polystyrene (LS-1010) and two polydisperse polystyrene latexes prepared in our laboratory (2) where the concentration of functional monomer, Cops II (Alcolac-ammonium salt of a short chain vinyl sulfonate), added to the recipe was 10 3 and 10 -M for and C, respectively. 

Table 1. Two sets of polystyrene latexes prepared with various surfactants...

Molecular weight distributions of the seed polystyrene latex prepared by reverse iodine transfer polymerization... 

All polystyrene latexes prepared by persulfate initiation may be shown to be negatively charged by electrophoresis. That is, all but one, which was discovered after years of storage at the Dow Chemical Co. to be electrically neutral, but very stable. The surface groups on this now famous latex are evidently all hydroxyl [31]. The sulfate groups originally present all must have hydrolyzed slowly upon standing ... 

Journal of Applied Polymer Science 68, No.8, 23rd May 1998, p.1257-67 PHOTON TRANSMISSION TECHNIQUE FOR STUDYING FILM FORMATION FROM POLYSTYRENE LATEXES PREPARED BY DISPERSION POLYMERIZATION USING VARIOUS STERIC STABILIZERS Pekcan O Arda E Kesenci K Piskin E Istanbul,Technical University Trakya,University Hacettepe,University... 

K. Kato, M. Kobayashi, K. Esumi, K. Me-guro. Interaction of pigments with polystyrene latex prepared using a zwitterionic emulsifier. Colloids Surf. 1987, 23,... 

According to the Verwey-Overbeek theory of colloidal stability (12), the smaller the particle size of a colloidal sol, the higher the surface charge required to give it stability. This is confirmed by our earlier work (2) with polystyrene latexes prepared with persulfate ion as initiator and subjected to ion exchange it is also... 

Application of the stirring test for present purposes makes use of a polystyrene latex prepared at a low level of stability with potassium palmitate as the sole stabilizer, as mentioned in an earlier section of this paper. The latex has good shelf stability but practically zero stirring stability. It is used in the following manner. 

Figure 1 demonstrates these effects by means of the particle size distribution of polystyrene latexes prepared with both types of inisurf. The polymerizations are carried out at 90 °C with 100 g of water, 10 g of styrene, and 0.25 g of 2,2 -azobis(N-2 -methylpropanoyl-2-amino-decyl-l-sulfonate) as gemini inisurf (Fig. la) and 1.292 g of bis(2-phenyl ethyl)-2,2 -azodiisobutyrate (Fig. lb) as conventional surface-active initiator, respectively. 

According to Krieger [38], seeded polystyrene latexes prepared with KPS and SPM were used to study its coverage by SAU. The surface yield of carboxylic groups was limited to the range 25-35%. 

Visualization of the QDs within the latex particles is the most reliable proof of their existence. Transmission electron microscopy [TEM] micrographs of certain polystyrene latexes prepared are shown in Figure 6.19. 

Figure 9.15 Monodisperse polystyrene latexes prepared by reverse recondensation method (A) 1.5 pm polystyrene seed particles, (B) 5.2 pm, (C) 7.5 pm, (D) 10.2 pm particles swelled from (A) particles (Reproduced by permission of Elsevier Science from ref. 87)...

Serizawa and Akashi [95] analyzed the monolayer adsorption of polystyrene latex particles with cationic polyvinylamine grafted on their surface, while Serizawa et al. [96,97] used commercial anionic latex particles. Both types of particles were adsorbed on polyelectrolyte-coated substrates previously prepared by alternating adsorption of cationic and anionic polyelectrolytes such as polyallylamine hydrochloride (PAH) and polystyrene sulfonate sodium salt (PSS) according to the method described by Decher [164]. Using... 

Heller and Tabibian (13) noted that errors, due to laterally scattered light and the corona effect, as large as to cause a 30 reduction in measured turbidity, may result if instruments which are perfectly suitable for ordinary absorption measurements are used for turbidity measurements without proper modifications. To evaluate the performance of our turbidity detector, particle suspensions of various concentrations of several polystyrene latex standards were prepared. Their extinction coefficients were measured using both a bench-top UV spectrophotometer (Beckman, Model 25) and the online detector (Pharmacia). 

Figure 10. Electron micrograph of composite silica-polystyrene latex system,SPL(-), prepared by using bare silica particles as the seed.

Figure 13. Gel permeation chromatogram of polystyrene latex, (PL), prepared by emulsifier-free emulsion polymerization at 1 5 °C(in the absence of silica particles).

Ali, S. A. Sengupta, M. J., Preparation and characterization of monodisperse polystyrene latexes of varying particle sizes without the use of surfactants, Polym. Mater. Sci. Eng. 1991, 8, 243 250... 

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. 

Polystyrene latexes were similarly prepared by Ruckenstein and Kim [157]. Highly concentrated emulsions of styrene in aqueous solutions of sodium dodecylsulphate, on polymerisation, yielded uncrosslinked polystyrene particles, polyhedral in shape and of relative size monodispersity. Interestingly, Ruckenstein and coworker found that both conversions and molecular weights were higher compared to bulk polymerisation. This was attributed to a gel effect, where the mobility of the growing polymer chains inside the droplets is reduced, due to increased viscosity. Therefore, the termination rate decreases. 

High molecular weight monodisperse polystyrene latexes have been prepared by this method [158]. A number of factors were found to influence the size and dispersity of the particles. The size decreased with increasing surfactant concentration and decreasing internal phase volume, and a more monodisperse latex... 

Seed polymerization using a polystyrene latex was used by Gaschler et al. (3) to prepare aqueous styrol-butadiene polymer dispersions. 

Monodisperse spheres are not only uniquely easy to characterize, but also very rarely encountered. Polymerization under carefully controlled conditions allows the preparation of the polystyrene latex shown in Figure 1.8. Latexes of this sort are used as standards for the size calibration of optical and electron micrographs (also see Section 1.5a.3). However, in the majority of colloidal systems, the particles are neither spherical nor monodisperse, but it is often useful to define convenient effective linear dimensions that are representative of the sizes and shapes of the particles. There are many ways of doing this, and whether they are appropriate or not depends on the use of such dimensions in practice. There are excellent books devoted to this topic (see, for example, Allen 1990) and, therefore, we consider only a few examples here for the purpose of illustration. 

A polymer called latex, prepared from a monomer that contains organic groups, is deposited as small spheres (0.1—0.3 pm in diameter) on the support to form a continuous film about 1—2 pm thick. The support is made of silica microspheres or spheres of polystyrene of about 25-50 pm diameter (Fig. 4.4). 

Polystyrene latexes have been prepared using persulfate initiator for many years, but only recently have methods been developed to determine the number and loci of the sulfate surface groups. To determine these surface groups, the latex is cleaned to remove the adsorbed emulsifier and solute electrolyte, then the surface sulfate groups in the H+ form are titrated conductometrically with base. The latexes can be cleaned effectively by ion exchange (2-5) or serum replacement (6) dialysis is not effective in removing the adsorbed emulsifier and solute electrolyte (3,5,6). +... 

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