Polystyrene determination

Structural parameters of crosslinked polystyrene determined from tension-deformation dependence and swelling in solvents of different activity. Collection Czech. Chem. Commun. 32, 1554 (1967). 

Kawata, K. Imagawa, I. Nakata, M., "Cloud-Point Curves of Ternary System Nitroethane + Cyclohexane + Polystyrene Determined by a Novel Method," Polym. J., 23, 233... 

Fig. 4. Comparison of a molecular weight distribution of a thermally polymerized polystyrene determined by GPC with the mwd calculated for a most probable distribution...

KAW Kawate, K., Imagawa, L, and Nakata, M., Cloud-point curves of ternary system nitroethane + cyclohexane + polystyrene determined by a novel method, Polym. /., 23,233, 1991. 

A chloroform extract of the polystyrene is subject to excitation by ultraviolet radiation of wavelength 370 nm from a mercury vapour lamp and the fluorescence spectrum of the sample recorded over the range 400 - 440 nm. The reading from the fluorimeter is noted and the Uvitex OB concentration in the polystyrene determined by reference to a prepared calibration graph. 

P.T. Callaghan and D.N. Pinder, "Self-Diffusion of Random-Coil Polystyrene Determined by Pulsed Field Gradient Nuclear Magnetic Resonance Dependence on Concentration and Molar Mass,"... 

P. T. Callaghan andD. N. Finder. Self-diffusion ofrandom-coil polystyrene determined by pulsed field gradient nuclear magnetic resonance Dependence on concentration and molar mass. Macromolecules, 14 (1981), 1334-1340. 

The monolayer amount adsorbed on an aluminum oxide sample was determined using a small molecule adsorbate and then molecular-weight polystyrenes (much as shown in Ref. 169). The results are shown in the table. Calculate the fractal dimension of the oxide. 

From the ratio of activities and measured values of n, the average number of initiator fragments per polymer can be determined. Carry out a similar argument for the ratio of activities for polystyrene and evaluate the average number of initiator fragments per molecule for each polymer from the following datat ... 

Susceptibility to radiation damage must be considered seriously if reference samples are to be calibrated for use in place of absolute systems. For the measurement of absolute C He, H) cross sections, films of polystyrene (CH) (which is relatively radiation hard) have been used successfiiUy, the RBS determination of carbon providing implied quantitation for the hydrogen present in the film. For a durable laboratory reference sample, however, there is much to recommend a known ion-implanted dose of H deep within Si or SiC, where the loss of hydrogen under room temperature irradiation will be neghgible. 

For materials of equivalent density water-blown polyurethanes and the hydrocarbon-blown polystyrene foams have similar thermal conductivities. This is because the controlling factor determining the conductivity is the nature of the gas present in the cavities. In both of the above cases air, to all intents and purposes, normally replaces any residual blowing gas either during manufacture or soon after. Polyurethane foams produced using fluorocarbons have a lower thermal conductivity (0.12-0.15 Btu in fr h °F ) (0.017-0.022 W/mK) because of the lower conductivity of the gas. The comparative thermal conductivities for air, carbon dioxide and monofluorotrichloromethane are given in Table 27.3. 

The relationship between the increase in contact radius due to plastic deformation and the corresponding increase in the force required to detach submicrometer polystyrene latex particles from a silicon substrate was determined by Krishnan et al. [108]. In that study, Krishnan measured the increase in the contact area of the partieles over a period of time (Fig. 7a) and the corresponding decrease in the percentage of particles that could be removed using a force that was sufficient to remove virtually all the particles initially (Fig. 7b). 

The retentivity relative to solid particles (e.g., spherical particles of polystyrene of definite size) is found from experiments determining the amount of these particles in the suspension to be filtered before and after the filter media. The retentivity K is determined as follows where g, g" =amounts of solid particles in liquid sample before and after the medium, respectively. 

The non-bonded interaction energy, the van-der-Waals and electrostatic part of the interaction Hamiltonian are best determined by parametrizing a molecular liquid that contains the same chemical groups as the polymers against the experimentally measured thermodynamical and dynamical data, e.g., enthalpy of vaporization, diffusion coefficient, or viscosity. The parameters can then be transferred to polymers, as was done in our case, for instance in polystyrene (from benzene) [19] or poly (vinyl alcohol) (from ethanol) [20,21]. 

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