Poly interaction parameter

Of particular interest has been the study of the polymer configurations at the solid-liquid interface. Beginning with lattice theories, early models of polymer adsorption captured most of the features of adsorption such as the loop, train, and tail structures and the influence of the surface interaction parameter (see Refs. 57, 58, 62 for reviews of older theories). These lattice models have been expanded on in recent years using modem computational methods [63,64] and have allowed the calculation of equilibrium partitioning between a poly-... 

Figure 10 Polymer-water interaction parameter (%) of cross-linked poly(/V,/V-alkyl-substituted acrylamide) as a function of temperature. (From Ref. 32.)...

Although being qualitatively in agreement with experimental results, disagreements between experiment and theory remain. Besides the composition, /a, and the total degree of polymerization, N, all theoretical works refer to the segmental interaction parameter x This parameter can be estimated from a relationship to the solubility parameters. The ODT as a thermodynamic measure of the incompatibility was used to compare a set of symmetrically composed diblock copolymers from different hydrocarbons, polydimethyl-siloxane and poly(ethylene oxide) (PEO) [33]. While the behaviour of hydrocarbon diblock copolymers was successfully described by a consistent set of solubility parameters, this procedure failed for systems containing PEO. The... 

An example of the incorporation of an external component on the crystallization behavior of triblock copolymers was given by Schmalz et al. [126]. They obtained PS-fo-poly(ethylene-co-propylene)-fo-PE (PS-fo-PEP-fr-PE) triblock copolymers from the hydrogenation of PS-fr-PI-fo-PB. PS-fo-PEP-fr-PE triblock copolymers have the peculiarity that PEP and PE have an interaction parameter of 0.007 at 120 °C therefore, they form a homogeneous melt, which is segregated from the PS block and can be considered as an intermediate case between diblock and triblock copolymers. The crystallization of the PE block occurs at about 60 °C and the authors evaluated the influence of the incorporation of a solvent during the crystallization and segregation processes under... 

The solvent activity in a solution of polybutadiene in benzene was determined by measuring the vapor pressure / , of benzene over solutions containing various concentrations of poly-mer.f A plot of ln(p,// ) — In 4>, — (1 — /ri) 2 versus — in which/ is the vapor pressure of the pure benzene —yields a straight line having an intercept of zero and a slope equal to 0.33. Evaluate the interaction parameter x from this result. Is the 0 temperature above or below the experimental temperature Explain. 

Since there had not been any measurements of thermal diffusion and Soret coefficients in polymer blends, the first task was the investigation of the Soret effect in the model polymer blend poly(dimethyl siloxane) (PDMS) and poly(ethyl-methyl siloxane) (PEMS). This polymer system has been chosen because of its conveniently located lower miscibility gap with a critical temperature that can easily be adjusted within the experimentally interesting range between room temperature and 100 °C by a suitable choice of the molar masses [81, 82], Furthermore, extensive characterization work has already been done for PDMS/PEMS blends, including the determination of activation energies and Flory-Huggins interaction parameters [7, 8, 83, 84],... 

Peppas N, Merrill E. Determination of interaction parameter for poly(vinyl alcohol) in gels crosslinked from solution. Journal of Polymer Science 1976, 14, 459 464. 

In some but not so rare cases, however, reactivity of macromonomers was found to be apparently reduced by the nature of their polymer chains. For example, p-vinylbenzyl- or methacrylate-ended PEO macromonomers, 26 (m=l) or 27b, were found to copolymerize with styrene (as A) in tetrahydrofuran with increasing difficulty (l/rA is reduced to one half) with increasing chain length of the PEO [41]. Since we are concerned with polymer-polymer reactions, as shown in Fig. 3, the results suggest that any thermodynamically repulsive interaction, which is usually observed between different, incompatible polymer chains, in this case PEO and PSt chains, may retard their approach and hence the reaction between their end groups, polystyryl radical and p-vinylbenzyl or methacrylate group. Such an incompatibility effect was discussed in terms of the degree of interpenetration and the interaction parameters between unlike polymers to support the observed reduction in the macromonomers copolymerization reactivity [31,40]. Similar observations of reduction of the copolymerization reactivity of macromonomers have recently been reported for the PEO macromonomers, 27a (m=ll) with styrene in benzene [42], 27b with acrylamide in water [43], and for poly(L-lactide), 28, with dimethyl acrylamide or N-vinylpyr-rolidone in dioxane [44]. 

Homopolymer (A)/random copolymer (B) blends, poly(1)/poly(2-ran-3). Phase behavior may be discussed in terms of the interaction parameter XAB which is given in the mean-field approximation by [2, 3]... 

The degree of induction of the dissociation of PMAA in the presence of various polycations is estimated by its apparent dissociation constant (pKJ calculated from the potentiometric titration results as shown in Fig. 6, using the Henderson-Hasselbach equation (see Table 5). In the presence of polycations, pKa and one of the interaction parameters relative to adjacent ionic sites, n, decreases. This confirms the induction of dissociation. Furthermore, the difference in the composition of the polyelectrolyte complex composed of one kind of polycation and different poly(carboxylic acid)s, may be affected by pKa and the conformation of them. 

Regressed Interaction Parameters for Water-Dextran (Mn = 23,000)-Poly(ethylene glycol) (Mw = 6,750) at 273 K Using a Modified Flory-Huggins Model... 

Ashworth, A. J. Price, G. J., "Static Investigation of the Influence of Polymer Molecular Weight and Loading in the Gas Chromatographic Determination of Poly(dimethylsiloxane) Interaction Parameters," Macromolecules, 19, 358 (1986). 

Charlet, G. Ducasse, R. Delmas, G., "Thermodynamic Properties of Polyolefin Solutions at High Temperature 2. Lower Critical Solubility Temperatures for Polybutene-1, Polypen-tene-1 and Poly(4-methylpentene-1) in Hydrocarbon Solvents and Determination of the Polymer-Solvent Interaction Parameter," Polymer, 22, 1190 (1981). 

Gekko, K. Matsumura, K., "Interaction Parameters of Poly(o-Chlorostyrene)- Solvent Systems," Bull. Chem. Soc. Japan, 46, 1554 (1973). 

Muramoto, A., "Dependence of Interaction Parameter on Molecular Weight and Concentration for Solutions of Poly(dimethylsiloxane) in Methyl Ethyl Ketone," Polymer, 23, 1311 (1982). 

Walsh, D. J. McKeown, J. G., "Compatibility of Polyacrylates and Polymethacrylates with Poly(vinyl chloride) 2. Measurement of Interaction Parameters," Polymer, 21, 1335 (1980). 

In the case of polystyrene blends with poly(vinyl methyl ether) two phase behaviour was found for blends from various chlorinated solvents whereas single phase behaviour was found for blends from toluene The phase separation of mixtures of these polymers in various solvents has been studied and the interaction parameters of the two polymers with the solvents measured by inverse gas chromatography It was found that those solvents which induced phase separation were those for which a large difference existed between the two separate polymer-solvent interaction parameters. This has been called the A% effect (where A% = X 2 Xi 3)-A two phase region exists within the polymer/polymer/solvent three component phase diagram as shown in Fig. 2. When a dilute solution at composition A is evaporated, phase separation takes place at B and when the system leaves the two phase region, at overall... 

The utility of the DSC for studying polymer-polymer miscibility has been demonstrated for poly(vinyl chloride)/nitrile rubber polyfvinyl methyl ether)/poly-styrene and poly(2,6-dimethyl 1,4-diphenylene oxide)/poly(styrene-co-chloro-styrene)It has also been particularly useful for measuring the melting point depressions of crystalline polymers in blends Mn order to calculate the interaction parameter as will be discussed later. 

Since the initial work of Smidsrod and Guillet numerous investigators have used I.G.C. to determine physicochemical parameters characterising the interaction of small amounts of volatile solutes with polymers Baranyi has shown that infinite dilution weight fraction activity coefficients, interaction parameters and excess partial molar heats of mixing can be readily determined with this technique. Partial molar heats and free energies of mixing, and solubility parameters of a wide variety of hydrocarbons in polystyrene and poly(methyl methacrylete) have been determined The temperature dependence of the interaction parameter between two polymers has also been studied... 

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