Dilute-Solution Properties of Chlorosulfonated Polyethylene. Il Theta Composition and Expansion Coefficient
01 Feb 1987-Journal of Macromolecular Science, Part A (Taylor & Francis Group)-Vol. 24, Iss: 2, pp 221-226
TL;DR: In this paper, the authors report the theta composition for chlorosulfonated polyethylene (CSP) in a solvent-nonsolvent mixture, viscometric data under theta conditions, and the expansion coefficients.
Abstract: It is well recognized that a polymer is under theta conditions if the second virial coefficient A2 is zero and the mean square radius of gyration of the polymer is proportional to the square root of its molecular weight. For any single solvent or a mixture of solvents, this condition prevails at a certain temperature, the theta temperature. Here, the polymer chains are said to be unperturbed as they are not affected by long-range interactions. In this note we report the theta composition for chlorosulfonated polyethylene (CSP) in a solvent-nonsolvent mixture, viscometric data under theta conditions, and the expansion coefficients. Different theoretical expressions are also examined in terms of the present data.
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TL;DR: In this paper, the authors investigated the behavior of poly(dimethylsiloxane-co-diphenyloxane)s under good and theta solvent conditions by using turbidimetry and viscosimetry.
Abstract: In this work, we investigated the behavior of poly(dimethylsiloxane-co-diphenylsiloxane)s under good and theta solvent conditions by using turbidimetry and viscosimetry. The evolution of the optical properties as a function of the solvent quality allowed the composition of the methylbenzene/methanol mixtures at the theta point to be determined. The intrinsic viscosity was determined in good (methylbenzene) and theta (methylbenzene/methanol) solvents at T = 298 K using different approaches. The unperturbed dimension parameters were calculated and are discussed as a function of copolymer composition. The introduction of the diphenylsiloxane units into a poly(dimethylsiloxane) chain results in an increase in the unperturbed dimensions as a consequence of the decrease in chain flexibility.
22 citations
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TL;DR: In this article, the compatibility of polyvinylchloride (PVC) and polychloroprene (PCP) blends has been studied and carried out with respect to their compatibility.
Abstract: Polyvinylchloride (PVC) and polychloroprene (PCP) blends have been studied and carried out with respect to their compatibility. Compatibility of the system PVC/PCP is determined by Zelinger–Heidingsfeld criterion at 30°C. The Stockmayer–Fixman equation relates intrinsic viscosity, and M w of polymers is used to calculate polymer–solvent interaction. Results are corroborated with thermal analysis of the blend system. It is found that, although PVC and PCP are incompatible in general, they exhibit limited compatibility at high PCP concentration.
12 citations
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TL;DR: In this paper, the effect of the solvent quality on the thermodynamic behavior of polydimethyldiphenylsiloxane copolymer by using turbidimetry and viscosimetry was investigated.
Abstract: In this work we investigate the effect of the solvent quality on the thermodynamic behavior of the polydimethyldiphenylsiloxane copolymer by using turbidimetry and viscosimetry. The turbidimetric method was used for the determination of the composition of the solvent mixture at the theta point. The experimental data obtained by using the capillary viscometry both in good and theta solvent conditions have been processed by using classical Huggins equation and new Wolf model (2007), which allows the calculation of intrinsic viscosities and other hydrodynamic parameters. The results obtained by using the two approaches were discussed comparatively. The conformational properties of copolymer in solution depend on their molecular structure, which is essentially dominated by the solvent quality, reflecting the balance of the interactions between the polymer chains and each solvent and that between solvent molecules.
11 citations
References
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TL;DR: The results of an extensive study of some dilute solution properties of a series of linear, homogeneous (anionically prepared) polystyrenes over a wide temperature interval (10°
Abstract: The results of an extensive study of some dilute solution properties of a series of linear, homogeneous (anionically prepared) polystyrenes (48<10−4M<440) over a wide temperature interval (10°
582 citations
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TL;DR: In this article, the effect of volume exclusion on the mean square radius of gyration s2 is treated by use of the empirical expression W0(s)=const s6exp[−(7/2)〈s2〉0−1s2] for a system of linear chain molecules unperturbed by volume exclusion.
Abstract: The effect of volume exclusion on the mean‐square radius of gyration s2 is treated by use of the empirical expression W0(s)=const s6exp[−(7/2)〈s2〉0−1s2] for the statistical distribution of s for a system of linear chain molecules unperturbed by volume exclusion. Segment interactions within the perturbed molecule are treated in the smoothed‐density approximation. The result is α5—α3=Azh(z/α3), where α2=〈s2〉/〈s2〉0, A is a numerical constant, z is the usual parameter proportional to the excluded volume for a segment pair and to the square root of the chain length, and h(ζ) is a function which decreases by almost one‐half as ζ increases from 0 to ∞. Asymptotic dependence of α2 on the ⅕th power of the chain length is thus confirmed. Extremely long chains, exceeding 106 bonds, would be required however for realization of this limiting behavior.
124 citations
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TL;DR: In this paper, the intrinsic viscosities of polystyrene and polyisobutylene fractions in good and in ideal solvents were examined from the point of view of their dependence on molecular weight.
Abstract: Intrinsic viscosities of polystyrene and polyisobutylene fractions in good and in “ideal” solvents have been examined from the point of view of their dependence on molecular weight. A compilation of results is presented which covers exceptionally wide ranges, from several thousand to several to million, in molecular weight. The intrinsic viscosity in an “ideal” solvent (i.e., cyclohexane at 34°C. for polystyrene, or benzene at 24° for polyisobutylene) is remarkably well fitted over the molecular weight range cited above by the relation:
where K is a constant, independent of molecular weight, for a particular polymer at a given temperature. The molecular expansion factor α3 which applies in good solvents (e.g., toluene for polystyrene and cyclohexane and diisobutylene for polyisobutylene) as calculated from:
increases with molecular weight approximately in accordance with the relationship:
However, the quantity (α5 − α3)/M1/2 changes appreciably with M in some cases. This is particularly true for molecular weights below 50,000. Results of an examination of the effect of rate of shear on the viscosity of polystyrene in benzene at 25° and in cyclohexane at 34°, and of the intrinsic viscosity-molecular weight relation for polystyrene in benzene at 25°, are reported.
103 citations
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TL;DR: In this article, the statistical radius of polychloroprene (PCP) in methyl ethyl ketone (MEK), n‐butyl acetate, and carbon tetrachloride at 25°C and in trans-decalin at temperatures ranging from 1° to 50°C were obtained.
Abstract: Data of the statistical radius 〈 S2 〉1 / 2 and the second virial coefficient A2 were obtained for sharp fractions of polychloroprene (PCP) in methyl ethyl ketone (MEK), n‐butyl acetate, and carbon tetrachloride at 25°C and in trans‐decalin at temperatures ranging from 1° to 50°C. MEK at 25°C and trans‐decalin at 2°C were found to be theta solvents for PCP. From these data two dimensionless quantities defined by αs2 = 〈 S2 〉 / 〈 S2〉0and Ψ = A2M1/2[4π3/2NA( 〈 S2 〉 / M3 / 2]−1 were calculated for all combinations of molecular weight M, solvent species, and temperature, where 〈 S2 〉0 is the value of 〈 S2 〉 under θ conditions and NA is Avogadro's number. These two quantities should be functions of a single parameter z, usually known as the interaction parameter, which is proportional to M1/2. With the data for these quantities from the present experiments on PCP as well as from Berry's experiments on polystyrene, comparative tests of typical theories for the excluded‐volume effects on dilute polymer solutions ...
52 citations