The Effect of Environment on The Fatigue and Fracture Response of Advanced Polymers and Composites

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ABSTRACT CTS-9321887 William Marsh Rice University P. I.: Riki Kobayashi A new five-parameter extended corresponding states model has been developed for viscosity and proton spin-lattice relaxation rate applicable to a variety of hydrocarbons in the dense fluid phase. Simple mixing rules allows extension of the model to mixtures. This proposed model is shown to bring improvements over the viscosity model of Ely and Hanley 1, 2 , for cyclic and branched alkanes, and their mixtures with n-paraffins. The corresponding states treatment of the proton spin-lattice relaxation rate, R1, yields a new correlation between R1 and temperature for saturated hydrocarbons, spanning three different processes of spin relaxation (i.e. spin-rotation, intramolecular and intermolecular dipole-dipole mechanisms). Accurate correlations between {SYMBOL 104 \f "Symbol"} are generated for pure and mixed fluids, with observed root-mean-square deviations of less than 8.0%. This new approach utilizes shape factors 3 to properly predict p-v-t surfaces; and two additional constants to account for transport. The new parameters, {SYMBOL 103 \f "Symbol"} for viscosity, and {SYMBOL 98 \f "Symbol"} for R1, mainly arise from hindered rotation of polyatomic molecules. The four-parameter corresponding states treatment, utilizing only the shape factors 3 , yields correlations of comparable accuracy, when confined to long-chain alkanes.