Radius of polystyrene

Fig. 18. Log tv against the log of the concentration of aikyl trimelhyl ammonium bromides of various chain lengths . C,e . C,j A, C (, 0> Cg , C4.. For comparison, data for potassium bromide is included. A- Radius of polystyrene latex particles = 48 nm. Reproduced with permission of American Chemical Society.

Figure 11 Hydrodynamic radius of polystyrene microlatex particles as a function of the weight ratio of surfactant to monomer. Full line, CTAB dashed line, TDEA-Cu. (From Ref. 88.)...

Antonietti and Nestl [88] reported a study using a new class of metallosurfactants that allowed them to reduce both particle size and surfactant concentration. Figure 11 shows the variation of the hydrodynamic radius of polystyrene particles as a function of the weight ratio of surfactant to monomer SIM) for microemulsions based on a classical surfactant, cetyltrimethylammonium chloride (CTAB) and the metallosurfactant tetradecyl-diethanolamine copper (TDEA-Cu). With this class of surfactants, the authors succeeded in getting a particle diameter as low as 14 nm (width of the distribution = 0.38), with an SIM value of 3. This results in a considerable surface area ( 500 m /g), which renders these systems of interest for subsequent functionalization. 

Figure 47 demonstrates, that experimental data on the change of the hydrodynamic radius of polystyrene particles versus the concentration of the latex lie on a straight line. Therefore, the reversible deformations of adsorption layer takes place under the action of electrostatic forces. 

Transmission electron microscopy was performed on the same sample and the radius of polystyrene spheres was found to be 92A. Estimate the volume fraction of polystyrene. The molar mass of the triblock = 90 kg mol and assume the density p = 1.05... 

Fig. 4. The contact radius as a function of the square root of the particle radius for polystyrene spheres on a silicon substrate (from ref. [64]).

Let us first assume that we have a spherical particle with a radius of 5 p.m similar to an idealized toner particle, which is comprised of polystyrene, in contact with an electrically conducting substrate. A typical electric charge on a toner particle of that size is of the order of 10" " C. The Hamaker coefficient (Eq. 15) for such as system would be about 1.5 eV. 

Example 2.20 A cylindrical vessel with an outside radius of 20 mm and an inside radius of 12 mm has a radial crack 3.5 mm deep on the outside surface. If the vessel is made from polystyrene which has a critical stress intensity factor of 1.0 MN calculate the maximum permissible pressure in this vessel. 

The conformation of polymer chains in an ultra-thin film has been an attractive subject in the field of polymer physics. The chain conformation has been extensively discussed theoretically and experimentally [6-11] however, the experimental technique to study an ultra-thin film is limited because it is difficult to obtain a signal from a specimen due to the low sample volume. The conformation of polymer chains in an ultra-thin film has been examined by small angle neutron scattering (SANS), and contradictory results have been reported. With decreasing film thickness, the radius of gyration, Rg, parallel to the film plane increases when the thickness is less than the unperturbed chain dimension in the bulk state [12-14]. On the other hand, Jones et al. reported that a polystyrene chain in an ultra-thin film takes a Gaussian conformation with a similar in-plane Rg to that in the bulk state [15, 16]. 

Rupture of fractal (flocculated) aggregates of polystyrene latices in simple shear flow and converging flow was studied by Sonntag and Russel (1986, 1987b). For simple shear flow and low electrolyte concentrations, the critical fragmentation number decreases sharply with agglomerate radius (R) as... 

Figure 3 Radius of gyration, Rg, and hydrodynamic radius, Rh, versus temperature for polystyrene in cyclohexane. Vertical line indicates the phase separation temperature. 

Hyperbranched polymers have also been prepared via living anionic polymerization. The reaction of poly(4-methylstyrene)-fo-polystyrene lithium with a small amount of divinylbenzene, afforded a star-block copolymer with 4-methylstyrene units in the periphery [200]. The methyl groups were subsequently metalated with s-butyllithium/tetramethylethylenediamine. The produced anions initiated the polymerization of a-methylstyrene (Scheme 109). From the radius of gyration to hydrodynamic radius ratio (0.96-1.1) it was concluded that the second generation polymers behaved like soft spheres. 

Figure 3.23 The tertiary electroviscous effect observed for particles of polystyrene latex with a copolymer of polyacrylic acid at the outer surface. The experimental points were obtained at pH 3 and 10. The dry particle radius was 75 nm and Ka 25...

Figure 5.18 The high frequency shear modulus versus volume fraction for a polystyrene latex for three different electrolyte concentrations. The symbols are the experimental data and the solid lines are calculated fits using a cell model. The radius of the latex particles was 38 nm...

GPC calibration curves are established based on the radius of gyration of known-molecular-weight polymers, such as well characterized, narrow-molecular-weight distribution polystyrene. Branched polymers have a lower radius of gyration for their molar mass than the corresponding linear molecule. Thus, as branching increases the GPC numbers become less and less accurate and so should only be used for trends, and not exact calculations as some authors have done. 

Figure 12. Radius of poly(dimethyl slloxane) phase as a function of weight fraction In cross-poly(dimethyl slloxane)-Inter-cross-polystyrene sequential IPN s with three different crosslink densities of network I. Broken lines are theoretical values from...

The radius of gyration of polymer coils can be determined independently from light scattering. Fox and Flory measured both Rg and [17] for various molecular weight fractions of polystyrene in various solvents at several temperatures. The following results were obtained ... 

The equilibrium constant is called the selectivity coefficient, because it describes the relative selectivity of the resin for Li+ and Na+. Selectivities of polystyrene resins in Table 26-3 tend to increase with the extent of cross-linking, because the pore size of the resin shrinks as cross-linking increases. Ions such as Li+, with a large hydrated radius (Chapter 8 opener), do not have as much access to the resin as smaller ions, such as Cs+, do. 

MWGPC weight average M from gel permeation chromatography, relative to polystyrene standards. Rg radius of gyration. 

The morphologies of polystyrene-F-polybutadiene (PS-F-PBD) diblock copolymers confined in a nanopore were observed by Shin and Xiang (Shin et al., 2004), in which a lot of attentions were paid to the layer number of the concentric cylinder barrel structure as a function of the nanopore radius. In this work, the symmetrical and asymmetrical... 

Sample balancing problem. Let us consider the multi-cavity injection molding process shown in Fig. 6.54. To achieve equal part quality, the filling time for all cavities must be balanced. For the case in question, we need to balance the cavities by solving for the runner radius R2. For a balanced runner system, the flow rates into all cavities must match. For a given flow rate Q, length L, and radius R, solve for the pressures at the runner system junctures. Assume an isothermal flow of a non-Newtonian shear thinning polymer. Compute the radius R2 for a part molded of polystyrene with a consistency index (m) of 2.8 x 104 Pa-s" and a power law index (n) of 0.28. Use values of L = 10 cm, R = 3 mm, and Q = 20 cm3/s. 

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