Phase behavior separation

Tg of blend was measured at the scan rate of 5°C/min by Dynamic Mechanical Analyzer (Du Pont DMA 981), which was a resonant frequency measuring type. Tgs were determined by the peaks of the loss modulus peaks. 

The light source used in the light scattering experiment was He-Ne laser, attenuated to produce a power of lOmW, and the wavelength was 0.6328 pm. The thickness of the specimen for the light scattering experiment was 20 pm. 

The final morphology of specimens cured at different curing temperatures and composition was observed by SEM. Fractured surfaces of postcured specimens prepared in liquid nitrogen, were etched with methylene chloride before examining by SEM. 

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Tb clarify the effect of addition of a cationic HC surfactant on phase separation behavior in the mixed monolayers of anionic HC and FC surfactants polyion complexed with cationic polymers, the mixed monolayers containing three amphiphilic components complexed with PVA were transferred on various substrate plates and studied by AFM, FFM, SSPM, and SIMS. As a cationic surfactant, ODTMAC was examined. 

In principle, many organosilanes can be used as a second precursor to form the organo-silica monolith. Various coprecursors reported for the fabrication of hybrid organo-silica monolithic columns for EC or CEC are listed in Table 8.1. The structure of the organo-silica material is affected by the ratio of the tetralkoxysilane to the alkyltrialkoxysilane in the sol-gel reactions, the type of precursor used, and the processing parameters. This can be seen, for example, in the phase separation behavior of... 

The Flory-Huggins equation (Eq. 10) allows one to reconstruct schematic phase diagrams to express the phase separation behavior as discussed below. 

Equation (21) reduces to Eq. (19) if polar and hydrogen bonding interactions are neglected. Hence, not the absolute value of the solubility parameter, as suggested by the simplified Hildebrand concept, but its individual contributions must be considered in order to express the solution and phase separation behavior. Thus, even though the norm of the solubility parameter of various solvents is constant, the partial contributions can be very different, resulting in a totally different solution and phase separation behavior respectively. 

Influence of the Solubility Parameter on the Phase Separation Behavior... 

To illustrate the influence of the solubility parameter on the phase separation behavior, a series of solvents has been selected which have either different values... 

If hexane is used as the low molecular weight liquid, the desired phase separation is observed when precursor mixtures containing 6-15 wt % hexane are cured isothermally at 40 °C. Further discussion of the phase separation behavior requires more detailed consideration of the schematic phase diagram, as presented in Fig. 17, which resembles the real phase diagram shown in Fig. 13. Experimentally it is found, that no phase separation occurs with hexane concentrations equal to or lower than 5 wt %. Hence the critical amount for phase separation, (j)p, is given by the intercept of the binodal line and the imaginary value of Hence no phase separation occurs if is reached before the metastable region is entered. 

Fig. 17. Schematic phase diagram explaining the phase separation behavior observed during the curing of epoxies in the presence of hexane...

Fig. 26. Influence of isothermal curing temperature on the phase separation behavior oi macroporous epoxies prepared via CIPS with cyclohexane...

The phase separation behavior during curing of polyetherimide (PEI) modified diglycidyl ether of bisphenol A (DGEBA) epoxy and PEI modified bisphenol A dicyanate (BPACY) were studied using SEM, light scattering, and dynamic mechanical analyzer. 

Other papers reported the phase separation behavior for the composition showing dual phase morphology [7,20,21,43-45], Delides et al. [43] proposed that the viscosity at the point of phase separation is sufficiently large enough to inhibit diffusion of the epoxy through the rubber (CTBN) and result in the generation of the occluded phase, which is the inclusion of epoxy domains within the rubbery phase. 

When the leuconitrile content was 1.0 mole %, the 1 mass % aqueous polymer solution showed Tc at 29.2 °C. Upon UV irradiation, the polymer did not show any more clear phase separation. The transmittance decreased gradually with increasing temperature above 36 °C. The absence of the phase separation behavior indicates that the hydrophobic interaction of the main chain is not strong enough to overcome the hydrophilidty of the photogenerated triphenyl-methyl cations and the polymer chain cannot shrink any further even at a higher temperature. 

The objective of the studies presented in this paper was to develop fundamental information for silanol intermediates concerning their kinetics of formation, equilibrium with other silicon-containing species, and phase separation behavior. Based on these results, it was the further objective of the studies... 

Reich S, Gordon JM (1979) Electric field dependence of lower critical phase separation behavior in polymer-polymer mixtures. J Polym Sci B Polym Phys 17(3) 371—378... 

In reality several aggregation numbers of the micelles occur, but from the simple equilibrium in (3.2) one can make a number of relevant conclusions. The larger the value of n, the more cooperative is the association and the more one approaches phase separation behavior. This is illustrated in Fig. 3.1 which shows plots, for two values of n, of the fraction of the amphiphile that enters the micelle as a function of the total amphiphile concentrations. A comparison with the experimental data in Figs. 

Unique Phase Separation Behavior of Surfactant Micelles. 451... 

UNIQUE PHASE SEPARATION BEHAVIOR OF SURFACTANT MICELLES... 

Aqueous solutions of neutral surfactants have two particularly important properties—their solu-bilizability and phase separation behavior—that can be exploited in order to develop a new viable extraction-preconcentration technique. 

The phase separation behavior of a sample of poly(N-vinyl-2.pyrrolidone) (PVP) in aqueous Na2S04 (0.55 M) containing a surfactant, sodium dodecyl sulfate (SDS), was reported [83], This phenomenon was studied in function of temperature and surfactant concentration as independent variables. Without surfactant, the polymer exhibits a lower solution temperature (LCST) of 28°C, above which it precipitates. At SDS concentrations of only 300 mg L-1, aggregation was prevented and the behavior of isolated polymer molecules could be studied. 

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