Hydrodynamisches verhalten gelöster polydimethylsiloxane

Haug, Von A.; Meyerhoff, G.

doi:10.1002/macp.1962.020530111

Cited by 78 publications

(28 citation statements)

References 20 publications

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“…The predicted exponents for e and E s ( e ϰ 0 y , E s ϰ 0 z ) using xϭϪ1 and xϭ1/(1Ϫ3) are shown in the first and the second row of Table I, respectively. Here, we used ϭ0.57 which is evaluated from the relationship between the molecular weight and the intrinsic viscosity for PDMS in toluene, 37 namely, []ϰM 3Ϫ1 . It can be seen from Table I that the theory predicts that the exponents for e and E s are higher in 0 Ͼ 0 ** than in 0 Ͻ 0 ** .…”

Section: ͑24͒mentioning

confidence: 99%

Crossover of the concentration dependence of swelling and elastic properties for polysiloxane networks crosslinked in solution

Urayama

Kohjiya

1996

The Journal of Chemical Physics

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We have investigated the preparation concentration dependence of the polymer volume fraction and the elastic modulus of the equilibrium swollen polydimethylsiloxane networks in toluene. The networks were prepared by the end-linking method in solution with a wide range of concentration. The network samples were attempted to be as small amount of structural defects as possible. The crossover has been observed for the preparation concentration dependence of the degree of equilibrium swelling and the elastic modulus. The crossover concentrations agree with each other, and are almost identical with the boundary concentration between the semidilute and the concentrated regime for the end-to-end distance of the polymer chain. The theoretical predictions which describe the experimental results have been derived as a function of the polymer volume fraction of preparation and swollen state, considering the effect of trapped entanglements on the elasticity and the concentration regime of preparation and swollen state. The good agreements of the theoretical predictions with the experimental results suggest that the trapped entanglements contribute to the elastic modulus together with the chemical crosslinks, and the crosslinking points moves affinely relative to the global polymer network on swelling.

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Section: ͑24͒mentioning

confidence: 99%

Crossover of the concentration dependence of swelling and elastic properties for polysiloxane networks crosslinked in solution

Urayama

Kohjiya

1996

The Journal of Chemical Physics

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“…Two different polymers were used, polystyrene (PS) for the repulsive case and polydimethylsiloxane (PDMS) for the attractive one. The 0 solvents were respectively cyclohexane (Ops = 34.5 °C) [20] and bromocyclohexane (OPDMS = 28 °C) [21]. Cyclohexane was purchased from Merck (Uvasol quality) and bromocyclohexane, purchased from Merck (zur Synthese) was redistilled under reduced pressure (20 torr) before use.…”

Section: Physics Abstractsmentioning

confidence: 99%

Study of the surface tension of polymer solutions: theory and experiments in theta solvent conditions

et al. 1983

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Resumé. 2014 Abstract. 2014 A study of the surface tension of semi-dilute polymer solutions in theta solvent conditions is presented. Theoretical predictions are given for the two cases when the interface is attractive or repulsive. The Cahn approach for the interfacial tension is used in order to calculate the interfacial tension in the mean field theory of polymer solutions. The measurements, were performed on two polymer theta solvent systems : polydimethylsiloxanebromocyclohexane at 29 °C and polystyrene-cyclohexane at 34°C for the attractive and repulsive cases respectively. The well-known ring method was used. The agreement between theory and experiments is good. The theoretical predictions and the results are compared with those obtained in good solvent case that we reported.in a previous paper. The transition 03B8 solvent-good solvent is studied for the attractive system.

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“…(12), ( 1 3) and (14) have to be calculated numerically. If, however, AGR is independent of the distribution functions and if the distribution functions are of the Schulz-Flory type (Eq.…”

Section: Eqs (3) and (4) Results Inmentioning

confidence: 99%

“…The analytical integration of Eqs. (12) and (13) The segment-molar activity coefficients fA and fB are related to AGR since RT lnfA and RT lnfB are the partial segment-molar quantities of AGR. The segmentmolar residual Gibbs energy AGR and, hence, fA and fg may be calculated according to the well-known model theories based on statistical mechanics such as the Huggins 2-parameter conceptI7).…”

Section: Eqs (3) and (4) Results Inmentioning

confidence: 99%

Phase separation of blends of polydisperse polymers: Comparison between experiment and theory for the system poly(dimethylsiloxane)/poly(ethylmethylsiloxane)

Enders

Stammer

Wolf

1996

Macro Chemistry & Physics

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Cloud point curves were measured turbidimetrically for blends (upper critical solution temperatures; UCSTs) of poly(ethylmethylsi1oxane) (PEMS) and four different samples of poly(dimethylsi1oxane) (PDMS); the weight average molar masses in kg/mol are 31.2 for PEMS and 10.4, 15.5, 18.1 and 24.0 for PDMS; all components have polydispersity indices D (= MJM") within the range from 1.82 to 2.67. Corresponding calculations on the basis of the Flory-Huggins theory (three adjustable parameters) account for the polydispersity; molecular weight distributions are represented by the generalized SchulzFlory equation. Calculated cloud point curves agree very well with those measured, if individual sets of parameters are admitted for each of the different mixtures. Even for an identical set of parameters the maximum deviations remain moderate. Realistic model calculations concerning the influences of D on cloud points and on critical points were performed with this set of parameters.For the present (only slightly endothermal) system, the precipitation threshold increases from 318 to 558.6 K as D , , , is raised from 1.87 to 4.00, keeping the number average degree of polymerization constant.--

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Hydrodynamisches verhalten gelöster polydimethylsiloxane

Cited by 78 publications

References 20 publications

Crossover of the concentration dependence of swelling and elastic properties for polysiloxane networks crosslinked in solution

Crossover of the concentration dependence of swelling and elastic properties for polysiloxane networks crosslinked in solution

Study of the surface tension of polymer solutions: theory and experiments in theta solvent conditions

Phase separation of blends of polydisperse polymers: Comparison between experiment and theory for the system poly(dimethylsiloxane)/poly(ethylmethylsiloxane)

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