Polymers in dilute solutions

Theta conditions in dilute polymer solutions are similar to tire state of van der Waals gases near tire Boyle temperature. At this temperature, excluded-volume effects and van der Waals attraction compensate each other, so tliat tire second virial coefficient of tire expansion of tire pressure as a function of tire concentration vanishes. On dealing witli solutions, tire quantity of interest becomes tire osmotic pressure IT ratlier tlian tire pressure. Its virial expansion may be written as... [Pg.2518]

In dilute polymer solutions, hydrodynamic interactions lead to a concerted motion of tire whole polymer chain and tire surrounding solvent. The folded chains can essentially be considered as impenneable objects whose hydrodynamic radius is / / is tire gyration radius defined as... [Pg.2530]

The effect of polymer additives on turbulent flow is at the origin of the important phenomenon of drag reduction and has found other industrial applications such as oil recovery and antimisting action. Drag reduction in dilute polymer solutions... [Pg.165]

Wiest JM, Bird RB, Wedgewood LE (1988) On coil-stretch transitions in dilute polymer solutions, RRC Report no. 116, University of Wisconsin-Madison, May... [Pg.178]

Leal LG (1986) In Rabin Y (ed) Studies of flow-induced conformation changes in dilute polymer solutions, Proceedings of the 1985 La Jolla Institute Workshop, Academic International Press, New York, p 5... [Pg.180]

J. F. Ryder and J. M. Yeomans, Shear thinning in dilute polymer solutions, J. Chem. Phys. 125, 194906 (2006). [Pg.145]

Jefri, M.A., Nichols, K.L., and Jayaraman, K. "Sedimentation of Two Contacting Spheres in Dilute Polymer Solutions," Proc. Svmp. Recent Dev. Struct. Continua.. 1985, 21-5. [Pg.662]

We present an improved model for the flocculation of a dispersion of hard spheres in the presence of non-adsorbing polymer. The pair potential is derived from a recent theory for interacting polymer near a flat surface, and is a function of the depletion thickness. This thickness is of the order of the radius of gyration in dilute polymer solutions but decreases when the coils in solution begin to overlap. Flocculation occurs when the osmotic attraction energy, which is a consequence of the depletion, outweighs the loss in configurational entropy of the dispersed particles. Our analysis differs from that of De Hek and Vrij with respect to the dependence of the depletion thickness on the polymer concentration (i.e., we do not consider the polymer coils to be hard spheres) and to the stability criterion used (binodal, not spinodal phase separation conditions). [Pg.245]

Attempts have been made to identify primitive motions from measurements of mechanical and dielectric relaxation (89) and to model the short time end of the relaxation spectrum (90). Methods have been developed recently for calculating the complete dynamical behavior of chains with idealized local structure (91,92). An apparent internal chain viscosity has been observed at high frequencies in dilute polymer solutions which is proportional to solvent viscosity (93) and which presumably appears when the external driving frequency is comparable to the frequency of the primitive rotations (94,95). The beginnings of an analysis of dynamics in the rotational isomeric model have been made (96). However, no general solution applicable for all frequency ranges has been found for chains with realistic local structure. [Pg.27]

Osaki,K., Sakato.K., Fukatsu,M., Kurata,M., Matusita,K., Tamura,M. Normal stress effect in dilute polymer solutions. III. Monodisperse poly-a-methylstyrene in chlorinated biphenyl. J. Phys. Chem. 74,1752-1756 (1970). [Pg.172]

Here we suggest that in dilute polymer solutions there very probably exists a high frequency dispersion region corresponding to the DTO model, and examine one possible case, the secondary loss observed in poly (propylene) oxide. [Pg.125]

The interesting question is whether in dilute polymer solutions there exists a low frequency dispersion region described by the RB theory, so that just as in the bulk polymer we have to contend with two dispersion regions. The existence of a RB dispersion region in polymer solutions may be associated with entanglement and hence a very sensitive function of polymer concentration and molecular weight. [Pg.125]

Berman NS, George WK (1974) Onset of drag reduction in dilute polymer solutions Phys Fluids 17 250... [Pg.157]

Berner C, Scrivener O (1980) Drag reduction and structure of turbulence in dilute polymer solutions Prog. Astronaut. Aeronaut., Vol 72 Viscous flow drag reduction (AIAA), 290... [Pg.158]

Gyr A, Mueller A (1975) Alteration of structures of sublayer flow in dilute polymer solutions Nature 253 185... [Pg.160]

Ishibashi O, Ihara M (1984) Drag coefficient of a setting particle in dilute polymer solutions Nippon Kogyo Kaishi 100 29... [Pg.161]

Akers LC, Williams MC (1969) Oscillatory normal stresses in dilute polymer solutions. J Chem Phys 51(9) 3834-3841... [Pg.241]

De Gennes PG (1977) Origin of internal viscosity in dilute polymer solution. J Chem Phys 66(12) 5825—5826... [Pg.243]

Other transport properties in dilute polymer solutions... [Pg.604]

Ruhr s group studied the separation of double- and single-stranded DNA restriction fragments in capillary electrophoresis with polymer solutions under alkaline conditions in epoxy-coated capillaries and found that at pH 11 the theoretical plate numbers exceeded several millions [96], At pH 12, single-stranded DNA molecules were still well separated in entangled hydroxyethylcellulose (HEC) solutions, but the resolution decreased significantly in dilute polymer solutions. [Pg.90]

J.S. Ultman and M.M. Denn, Anomalous heat transfer and a wave phenomenon in dilute polymer solutions, Trans. Soc. RheoL, 14 (1970) 307-317. [Pg.231]

Sedimentation, diffusion, viscometric and flow birefringence measurements in dilute polymer solutions have been applied for this purpose ° ... [Pg.163]

Recent studies in our laboratory were aimed at defining more closely the conditions governing Intramolecular excimer formation in dilute polymer solutions (15). An alternating copolymer of styrene with maleic anhydride or methylmethacrylate showed no excimer emission, confirming that interactions of other than neighboring phenyl residues made no significant contribution to... [Pg.193]

In Fig. 16 the maximum fluorescence intensity of ANS was plotted against the concentration of the polymers with different content of associative macromonomer (P6-P8). In diluted polymer solutions, the maximum fluorescence intensity increased gradually with increasing polymer concentration. At the same polymer concentration, ANS showed higher fluorescence intensity in a solution of polymer that contains more of the associative macromonomer 8. [Pg.189]

Using Eq. (3.77) for the size of the chain in a good solvent with intermediate excluded volume v in Eq. (8.25), and combining with the -solvent result of Eq. (8.25) with v= j2, yields a general expression for the Zimm time in dilute polymer solutions ... [Pg.314]

Du M, Maki Y, Tominaga T, Furukawa H, Gong JP, Osada Y, Zheng Q (2007) Friction of soft gel in dilute polymer solution. Macromolecules 40 4313 321... [Pg.246]

It is not well understood how torsional motion of a polymer side group is affected by the rest of the polymer chain in highly dilute solutions. In the case of intramolecular exciplex formation of l-(l-pyrenyl)-3-(4-N,N-dimethylaminophenyl) propane bonded to polystyrene [14], the rate of exciplex formation in dilute polymer solution is much slower than that of a reference small molecule system. [Pg.139]

The increase in sensitivity over standard DSC instruments and the ability to study reactions occurring in solution directly mean that HSDSC may be applied to the study of a range of systems not open to study by standard DSC. Typical examples include the denaturation of proteins, phase changes in lipid bilayers, phase transitions in dilute polymer solutions, and changes in structure of creams and emulsions. Although there are many systems that have been studied using HSDSC, the discussion that follows will concentrate on systems of biological or pharmaceutical relevance. [Pg.290]

In dilute polymer solutions, the polymer molecules are isolated from each other by regions of pure solvent, i.e., the polymer segments are not uniformly distributed in the lattice. In view of this, the Flory-Huggins theory is least satisfactory for dilute polymer solutions and only applies to concentrated solutions or mixtures. Furthermore, the interaction param-... [Pg.156]

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