Polymer fluids, high

Polymer-Fluid Equilibria and the Glass Transition Most polymer systems fall in the Class HI or Class V phase diagrams, and the same system can often change from one class into the other as the polymer s molecular weight changes. Most polymers are insoluble in CO9 below 100°C, yet CO9 can be quite sohible in the polymer. For example, the sorption of CO9 into silicone rubber is highly dependent upon temperature and pressure, since these properties have a large influence on the density and activity of CO9. 

A tetrapolymer consisting of 40 to 80 mole-percent of AMPS, 10 to 30 mole-percent of vinylpyrroMone, 0 to 30 mole-percent of acrylamide, and 0 to 15 mole-percent of acrylonitrile was also a suggested as a fluid loss additive [1061]. Even at high salt concentrations, these polymers yield high-temperature-stable protective colloids that provide for minimal fluid loss under pressure. 

Figure 10. LCT configurational entropy ScT as a function of the reduced temperature 5T = (T — To)/To for low and high molar mass F-F and F-S polymer fluids at constant pressure of P = 1 atm (0.101325 MPa). The product ScT is normalized by the thermal energy k To at the ideal glass transition temperature To- (Used with permission from J. Dudowicz, K. F. Freed, and J. F. Douglas, Journal of Physical Chemistry B 109, 21350 (2005). Copyright 2005 American Chemical Society.)...

Figure 13. Ratios T/ /To and Ti/Tg of the characteristic temperatures from Figs. 8a and 8b as a function of the inverse number l/M oi united atom groups in individual chains for constant pressure (P = 1 atm 0.101325 MPa)F-F (open symbols) and F-S (filled symbols) polymer fluids. The single data point denoted by refers to high molar mass F-S polymer fluid at a pressure of P = 240 atm (24.3 MPa).

Figure 15. The LCT configurational entropy s T (normalized as in Fig. 11) as a function of the reduced specific volume 8v = [v T) — v(T = To)]/v(T), which is a measure of the excess free volume in the polymer system. Different curves refer to the F-F and F-S polymer fluids and to low and high molar mass polymer chains.

Figure 17. Specific volume Vt and isothermal compressibility (at the glass transition temperature Tg) calculated from the LCT as a function of the inverse number l/M of united atom groups in single chains for constant pressure (P = I atm 0.101325 MPa) F-F and F-S polymer fluids. Both quantities are normahzed by the corresponding high molar mass limits (i.e., by...

Based on comparisons with experimental data at high temperatures, SS introduce the approximate relation for polymer fluids, [39, 40],... 

At temperatures much higher than Za, the polymer fluid formally undergoes a fluid-gas transition where the isothermal compressibility Kr diverges, but this high temperature regime is normally inaccessible in polymer systems because of thermal decomposition. 

The calculated LCT configuration entropy for high molar mass E-S polymer fluids at pressures of P = 1 atm and P = 240 atm equals 0.1933 and 0.2147, respectively, and can be regarded, to a first approximation, as pressure independent. 

Fluorinated polymers are by nature inert and nontoxic materials. A certain toxicity may however be incorporated from additives added, e.g. perfluorooctanoic acid or traces of monomers. In addition, toxic organo-fluorine compounds may be generated from these polymers by high temperature decomposition.6-64- 16-118 Biological effects of fluorocarbon fibers have been described.119 Toxicities of polychlorotrifluoroethylenc oils (hydraulic fluids) have also been discussed.202... 

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