High polymer solutions. Part I.—Vapour pressure of polystyrene solutions

Bawn, C. E. H.; Freeman, R. F. J.; Kamaliddin, A. R.

doi:10.1039/tf9504600677

Cited by 151 publications

(75 citation statements)

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“…Specifically, enthalpic interactions are reflected in the interaction parameter since this term describes the relative strength of cohesive and adhesive interactions. # has an entropic component and can also vary with temperature and composition (18,23,24).…”

Section: Enthalpy Of Mixing: Importance Of Intermolecular Interactionsmentioning

confidence: 99%

Theoretical and Practical Approaches for Prediction of Drug–Polymer Miscibility and Solubility

2006

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Purpose. Crystallization of drugs formulated in the amorphous form may lead to reduced apparent solubility, decreased rate of dissolution and bioavailability and compromise the physical integrity of the solid dosage form. The purpose of this work was to develop thermodynamic approaches, both practical and theoretical, that will yield a better understanding of which factors are most important for determining the ability of polymers to stabilize amorphous active pharmaceutical ingredients (API). Materials and Methods. Lattice based solution models were used to examine miscibility criteria in APIpolymer blends. Different methods were used to estimate the Flory

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Section: Enthalpy Of Mixing: Importance Of Intermolecular Interactionsmentioning

confidence: 99%

Theoretical and Practical Approaches for Prediction of Drug–Polymer Miscibility and Solubility

2006

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“…[12] In the present work, polystyrene standards of narrow molar mass distribution were investigated in a 1 000-fold interval of molar masses, with methyl ethylketone (MEK) as solvent. Polystyrene was already widely studied in a variety of solvents, including MEK, [13][14][15][16][17][18][19][20][21][22] so that our results can be compared to the earlier ones and reliable conclusions can be drawn. In addition, we have tried to optimize the measurement and data analysis protocols in order to help transforming the technique into a versatile and simple-to-use one also for non-globular systems.…”

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confidence: 90%

“…[44] When volume interactions have negligible effect, Porod-Kratky statistics are applied for the closely placed segment pairs. For distant segment pairs, excluded-volume effects are evaluated from the equation [15] (2) from ref., [14] (3) from ref., [18] (4) from ref., [19] and (5) which characterizes the thermodynamic quality of the polymer-solvent system, N is the number of statistical segments in the chain. This theory describes the hydrodynamic behavior of polymer chains in full range of thermodynamically goodness of solvent and in a very large scale of M.…”

Section: Estimation Of the Statistical Segment (Kuhn Segment) Length mentioning

confidence: 99%

Velocity Sedimentation and Intrinsic Viscosity Analysis of Polystyrene Standards with a Wide Range of Molar Masses

Perevyazko

Schubert

2010

Macro Chemistry & Physics

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Analytical ultracentrifugation is one of the key methods among the molecular hydrodynamic methods of polymer science, biophysics, and colloid science. The aim of this work is to demonstrate the possibilities of a modern instrument, the Beckman XLI Analytical Ultracentrifuge, coupled with the now available software for the molecular characterization of synthetic polymers. For this purpose the classical system polystyrene in methyl ethylketone was investigated. The samples of low polydispersity index were studied in a 1 000‐fold interval of molar mass values. The exhaustive analysis of such hydrodynamic values as velocity sedimentation coefficient, frictional ratio, concentration Gralen coefficient, and intrinsic viscosity, was done. The values of partial specific volume, refractive index increment, and hydrodynamic invariants were also determined and discussed. The estimation of the statistical segment length (or persistent length) of polystyrene chains was made taking into account the intrachain excluded volume and draining effects (Gray–Bloomfield–Hearst theory). The obtained experimental data and results of its analysis allow the conclusion that the method of velocity sedimentation, coupled with the numerical solution of the Lamm equation, represents a powerful absolute characterization method for molar mass determination of flexible polymers of low polydispersity in relatively poor solvent.magnified image

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“…It is also higher than curve 2 for the rubber-benzene system [5], and than curves [6, p . 518] for the polymersolvent systems polydimethylsiloxane (M = 2850)-benzene [7], polystyrene-toluene, and polystyrenebutanone [8], all three of which lie below curve 3 ( fig. 3) by varying amounts.…”

Section: Resultsmentioning

confidence: 99%

Heat of mixing of polybutadiene and benzene

Jessup¹

1959

J. RES. NATL. BUR. STAN.

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Meas urements have been made of the heat of mixing of polybutadiene and benzene at 26.9° C by means of a Bunsen-type calorimeter, in which diphenyl ether is the calorimetric medium. The results of these measurements can be represented by t he empirical equation t:;HM = 12 .0vj v2, where t:;HM is heat of mixing in joules per cm3, and VI and V2 are volume fraction s of sol vc n t and polymer, respectively. The data have been combined with previously r eported data on the activity of the solvent in this system to obtain values of t:;SJ, t he partial molal entropy of dilution. The curve of t:;S dRv~ versus V2 for this system lies above the calculatcd curve of t:;sN Rvt where t:;si is the "configurational entropy" of dilution, and also lies above the corresponding exp erime ntal curves for several other polymer-solvent systems.

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High polymer solutions. Part I.—Vapour pressure of polystyrene solutions

Cited by 151 publications

References 0 publications

Theoretical and Practical Approaches for Prediction of Drug–Polymer Miscibility and Solubility

Theoretical and Practical Approaches for Prediction of Drug–Polymer Miscibility and Solubility

Velocity Sedimentation and Intrinsic Viscosity Analysis of Polystyrene Standards with a Wide Range of Molar Masses

Heat of mixing of polybutadiene and benzene

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