Determination from probe-polymer

Sulfur dioxide was the major volatile product and was used as a probe to correlate the radiation resistance with polymer structure. The use of biphenol in the polymer reduced G(SO ) by 60% compared with bisphenol A based systems (Bis-A PSF). Surprisingly, the isopro-pylidene group was shown to be remarkably radiation resistant. The ultimate tensile strain decreased with dose for all polysulfones investigated and the rate of decrease correlated well with the order of radiation resistance determined from volatile product measurements. The fracture toughness (K ) of Bis-A PSF also decreased with irradiation dose, but the biphenol based system maintained its original ductility. 

In the vapor phase osmometry (VPO) technique, drops of solvent and solution are placed in an insulated chamber close to thermistor probes. Since the solvent molecules evaporate more rapidly from the solvent than from the polymer solution, a temperature difference results that is related to the molarity of the polymer (M), which can be determined if the heat of vaporization per gram of solvent (A) is known using the following relationship ... 

The experiment consists in the incubation of the labeled antigen (1) with increasing concentrations of MIP or NIP/CP, and (2) with the same set of concentrations but in the presence of a constant concentration of analyte sufficient to displace significantly the probe from the polymer [22]. Each point in the dilution curve should be determined at least by duplicate and preferably between five and ten replicates so that we can obtain not only the optimum polymer concentration for the assay but also an estimate of the standard deviation of the response at each point along the curves. The curve representing the difference (% bound label) of the bound label in the absence and in the presence of the analyte will render the optimum MIP concentration to be used in the assay. Using this approach we have optimized the amount of polymer required for the development of a fluoroimmuno-like assay for penicillin analysis [36],... 

Guillet and coworkers (8-10) have determined the solubility parameter of polymers from the probe-polymer interaction coefficients. They separated the interaction parameter into entropic and enthalpic contributions, such that Xi2=X h+Xs to yield, in combination with Hildebrand s solution theory, the following expression ... 

The degree of microcrystallite orientation in crystalline films can be determined from careful analysis of the polarized Raman scattering line intensities. Since the induced polarization (P) and incident electric field (E) of the probe laser are three-dimensional vectors related by the polarizability tensor (o), individual elements of the tensor ( ij) be determined from the line intensities establishing molecular orientation in materials. Molecular chain orientation in polymer glasses has been demonstrated by Raman and infrared dichroism studies (12). 

The photochromic probe method uses different probe molecules, usually substituted stilbenes and azobenzenes, and in this case the evaluation is based on the capacity of the probe molecules to undergo a trans-cis isomerization upon irradiation (Figure 4.2) [9]. This depends on the probe size and on the size of the FVE in which it is located. The probe molecules are dissolved in the polymer matrix, isomerization is induced by a strong UV lamp and the degree of isomerization is determined from the absorbance spectra before and after the isomerization. 

When a crystallizable polymer is cooled below its equilibrium melting temperature, the hierarchical structure formed can be probed by in situ scattering. Crystallization mechanisms can be determined by comparing the time evolution of the degi ee of crystallinity (wc) determined from WAXS and the total integrated scattering intensity or invariant during crystallization [27,38] from SAXS. 

Table 2. Mean values of polymer-polymer interaction parameters (%), determined for several probes, in PCL/PVC blends determined from inverse-phase gas chromatography at 120° C data taken from [72] ...

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