Rotational viscosities of different asphalt binders were determined at temperatures between 80°C and 185°C. Viscosity–temperature dependence of asphalt binders was described with the use of the Vogel–Tammann–Fulcher (VTF) and the William–Landel–Ferry (WLF) equations. The Vogel temperature ( Tv) and the glass transition temperature ( Tg) for different asphalt binders were determined by fitting experimental values of viscosity at different temperatures with these two equations. For asphalt binders, the difference between Tv and Tg was about 40K. Effects of asphaltenes, aging, chemical modification, and polymer content on these temperatures were evaluated. As asphaltene content increased, both temperatures, Tv and Tg, increased. Different polymers showed different effects on these temperatures. The values of Tv and Tg were correlated with the critical cracking temperature ( Tcr) determined through use of a bending beam rheometer and a direct tension tester. The results suggested that the correlations between Tv, Tg, and Tcr could be used to determine Tcr from the rotational viscosity results tested at high temperature. With simple rotational measurements, a quick estimation of Tcr of asphalt binders could be obtained. Liquid fragility theory was also used to study Tg of asphalt binders. Parameters determined with the VTF and WLF equations indicated that asphalt binders behaved as fragile liquids because of their non-Arrhenius behavior in the temperature range studied.
The vacuum ultraviolet photolysis and mass spectral cracking pattern have been used to elucidate the chemistry occurring during the gas phase γ radiolysis of ethylenimine. In the 147 nm photolysis of ethylenimine, the major primary reactions occurring are (1) C2H4NH→C2H4+NH, φ=0.38, and (2) C2H4NH→CH3+[H2CN], φ=0.47. The mass spectrum of ethylenimine indicates that in the γ radiolysis of ethylenimine, where ions as well as neutral excited states are produced, the mechanism includes the ionic analog of Reaction (2): C2H4NH+→CH3+H2CN+. The mass spectrum also suggests the inclusion of Reaction (10) in the γ-radiolysis mechanism: (10) C2H4NH+→C2H4N+ + H. Although it cannot be proven conclusively, because hydrogen atoms and ethylenimine radicals are produced in secondary reactions, spectroscopic evidence suggests that the neutral analog of Reaction (10) may occur in the 147 nm photolysis: (9) C2H4NH→C2H4N+H. Except for reaction (1), which has no ionic analog in the mass spectrometer and which probably occurs from a valence excited state, the similarity of the neutral and ionic reactions occurring in the 147 nm photolysis and γ radiolysis of ethylenimine suggests that the Rydberg excited state, (nN→4p), populated by 147 nm photons exhibits quasi-ionic behavior. It seems likely that useful correlations of vacuum ultraviolet photolyses (8–12 eV), γ radiolyses, and mass spectra should be possible for many polyatomic molecules which frequently exhibit Rydberg excitations at these energies.
The room temperature photolysis of 1,l-dichloroethane at 147 nm in the pressure range of 1.34-196.2 torr is characterized almost entirely by the molecular elimination of HCl, Cl,, and small quantities of HD.While it is possible that the C2HD arises, in part, from the decomposition of vibrationally excited ground states of C,H,Cl and/or CZHl, in this particlar case serious consideration has to be given to alternative explanations where the products of the primary processes are formed in electronically excited states. The 01,a elimination of molecular chlorine is not inconsistent with an increased degree of Cl-Cl interaction predicted for a "Rydberg" state of 1,1-C2HaCl,. Varying small yields of CH, are observed in the presence and absence of NO. The effect of large pressures of CF, on the quantum yields of the major products is extremely small. The extinction coefficient for 1,1-C2H,C1, at 147 nm and 296°K is 246 f 29 cm-'.atm-'.Acetylene is also produced.
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