Polymer/Solvent and Polymer/Polymer Interaction Studies (original) (raw)
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INVESTIGATING THE COMPATIBILITY OF POLYMERS IN COMMON SOLVENT
Journal of the Chilean Chemical Society, 2010
Polymers are considered as versatile material having number of applications. However, their properties depend upon the structure, molecular mass and its distribution and the interactions among polymer-polymer and polymer-solvent molecules. Hence it is necessary to synthesize a polymer with required specification, which is a difficult, time consuming and costly process. A highly successful alternative is to blend/ mix the existing polymers for the purpose. This process needs detail knowledge about the interactions and miscibility of polymers with each other. Therefore the objective of this study is to investigate the compatibility of polymers with reference to their concentration in the blend, using static and dynamic light scattering and Rheology of the material. For the purpose Polystyrene/ Polymethylmethacrylate, Polystyrene/Polyethylene glycol and Polymethylmethacrylate / Polyethylene glycol using benzene as common solvent systems have been investigated in detail. The variation in hydrodynamic radius with concentration of polymer in the blend is found to be a good tool to ascertain the compatibility of polymers. Viscosity results also second the light scattering observations. It has been concluded that the polymer's compatibility depends upon composition of the blend and compatible with in a certain range. The compatibility play key role in the conformational behavior of the polymers blend and the techniques used is quite sensitive to identify the phase separation point.
European Polymer Journal, 1970
It was established that there are discrepancies between the intrinsic viscosities of ternary systems and those calculated from results on the appropriate binary systems. Deviations from additivity of intrinsic viscosity values in binary systems and corresponding ternary systems were estabtished. The viscosity interaction parameters (b,3) for polymer-polymer, according to the model of Krigbaum and Wall, are dependent on the tool. wt, as well as on the natures of the polymers and solvent used. A simple empirical relationship was found between the viscosity interaction parameter (b23) and the Flory-Huggins interaction parameter polymer-polymer (a23).
Determination of interaction parameters for highly incompatible polymers
Polymer, 1996
Experiments and calculations were performed for the ternary system cyclohexane/polystyrene/polyisobutylene (CH/PS/PIB) to study the possibilities of determining the Flory-Huggins interaction parameters ~PS/Pm between these highly incompatible polymers. To that end XCH/PIB was determined (vapour pressure measurements and additional thermodynamic information) as a function of composition; XCH/PS and its concentration dependence could be taken from earlier experiments. Furthermore, the cloud point curve and some tie lines of the ternary system were measured. In the subsequent evaluation of these data, the phase diagram was calculated and XPS/Pm (as a function of concentration) adjusted until the theoretically calculated binodal line matches with the measured cloud points. The polymer/polymer interaction parameter thus obtained increases at 35°C from 0.416 in the limit of pure PS to 0.449 in the limit of pure PIB. This result agrees reasonably well with the prediction of the solubility parameter theory and is in good accord with information stemming from light scattering experiments in a ternary system under 'optical theta conditions'.
Polymer Engineering and Science, 1982
The solvent has an influence on the homogeneity of the poly(vinyl methyl ether)-polystyrene, PVME-PS blends Prepared by drying cosolutions. This influence has been analyzed in terms of the competition among polymer-polymer and polymer-solvent interactions. Model solutions have been prepared in which intermoleeular interactions correspond to the interactions in this blend and in some of the cosolutions. These interactions in the model solutions have been detected and identified by applying Rummens' method. The 13C NMR spectra have been determined for PVME and for styrene oligomer dissolved in n-alkanes, cyclohexane, diethyl ether, isopropyl methyl ether, diisopropyl ether, and chloroform, and for PVME dissolved in benzene, toluene, and cumene. The chemical shifts have been plotted against the parameter g2 = [(n22 − 1)/(n22 + 1)]2, where n2 is the refractive index of the solvent. If the structural segment represented by certain carbon and some solvent has an interaction that is stronger than dispersive, the chemical shift for this carbon will deviate from the line formed by its shifts in n-alkane solutions, these deviations indicate characters and intensities of the intermoleeular interactions. Results indicate that cyclohexane exhibits weak interactions with both of the polymers and does not interfere with their mutual interaction, leading to a compatible blend. Results also suggest that benzene and toluene interact in the PVME in the same manner as PS. This leads to a gradual increase of the number of polymer-polymer interactions as the concentration of the polymers is increased by solvent removal, resulting in a compatible blend. Chloroform apparently interacts more strongly with PVME than with PS but interacts strongly enough with both to restrict interaction among the two polymers. As the concentration of polymers in the cosolution is increased, PS forms a separate phase. This leads to an inhomogeneous blend when the solvent is evaporated.
Measurement of activities of solvents in binary polymer solutions
Fluid Phase Equilibria, 1999
Vapor liquid equilibrium data of nine binary solventq polymer systems were measured by a vacuum electro-microbalance cell. Tested solvents were n-heptane, n-octane, n-nonane, methanol, ethanol, n-propanol Ž. Ž. and water. Polymers were poly dimethylsiloxane, M : 26,000 , poly propylene oxide, M : 2000 and poly n n Ž. ethylene glycol, M : 600. Data obtained in the present study together with existing literature data were n correlated by UNIQUAC model. Reliability of the experimental apparatus and the data was discussed.
Solvent-polymer interactions in polybutadienes
Macromolecules, 1993
Infinite-dilution activity coefficients of 26 solvents in three polybutadienes were determined by inverse gas chromatography in the temperature range 40-100 "C. The polybutadienes have wellcharacterized structures and different molecular weights. The data are useful for the development of thermodynamic models for polymer-solvent interaction and for characterization. The results were fitted to the PHCT equation of state. The data indicate that activity coefficients depend on polymer molecular weight and structure.
International Standard Book Number-10: 1-4200-5102-4 (Hardcover) International Standard Book This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use.
The work reported in the previous Part on the binding of phenols and 0-substituted phenols by poly(vinylpyrro1idone) (PVP) in aqueous solution has been extended by studies of their effects on the solubility and solution viscosity behaviour of the polymer, using the same thirteen cosolutes, i.e. HOPhPhOH [where Ph = phenyl or phenylene (174-substitution in XPhY and 1,3-~ubstitutionin PhXY), E = ethylidene (CH,CH,), and G1 = 1-deoxy, 1-P-D-glucopyranosyl (' glucosyl ')I. Only four of these cosolutes precipitate the polymer, their critical precipitation concentrations c* in mol m-3, for 10 g dm-3 (1 % w/v) PVP K-90 at 20 OC, being: PhOH, 85; HOPhNO,, 17; HOPhOH, 50; HOPhOMe, 69. The viscosity measurements show that in general the intrinsic viscosity, [q], is reduced in the presence of the cosolutes (most markedly so by the precipitant cosolutes) ; parallel increases are seen in the Huggins slope parameter, k,. The importance of the acidic phenolic hydroxy group in these phenomena is shown by the small viscosity effects seen with PhOGl (which is not bound by the polymer) and with the three hydroxyethyl compounds PhOEOH, HOEOPhOEOH and Ph(OEOH),, by the low value of c* for the highly acidic cosolute HOPhNO,, and by c* decreasing with more phenolic hydrogen-bond donor/acceptor groups (PhOH-+ HOPhOMe-+ HOPhOH). The absence of precipitation with HOPhOGl, despite its phenolic hydroxy group and its high solubility, and the small viscosity effects it produces, parallel the ' inhibitory' effect of the glucosyl group seen in the binding behaviour with this cosolute and with PhOGl. With PhOMe and MeOPhOMe the solubility is evidently too low to show up any effects. Correlating the intrinsic viscosity with the binding ratio r (the average number of cosolute molecules bound per monomer unit of the chain) shows that there are two main forms of behaviour : (i) a simple linear dependence of [q] on r, which is seen with six cosolutes (HOPhNO,, PhOEOH, HOEOPhOEOH, Ph(OEOH),, PhPhOH and HOPhOH); and (ii) a linear dependence of [q] on r2, which is seen with four cosolutes (PhOH, HOPhOH, HOPhOMe and HOPhOGl). The results are interpreted on the basis of the reversible non-covalent cross-linking of the polymer chains by bound cosolute molecules, which explains the observed reductions in [q] and the parallel increases in k,, as well as the precipitation seen with four of the cosolutes. A statistical-mechanical model derived by Kuhn and coworkers, based on the cross-linking concept, is applied to the viscosity data, enabling the equilibrium constant for cross-linking to be calculated.
Viscometric study on the compatibility of polymer–polymer mixtures in solution
European Polymer Journal, 1999
The viscosity behaviour of mixtures formed by two uncharged polymers in dilute solution has been studied at 258C. The ternary systems assayed, and denoted solvent (1)/ polymer (2)/ polymer (3), have in common the poly(ether sulphone) (PES) as polymer 2, and poly(vinylidene¯uoride) (PVDF), poly(methyl methacrylate) (PMMA) or poly(styrene) (PS) as polymer 3. The intrinsic viscosity and the viscometric interaction parameters have been experimentally measured for the binary (solvent/polymer) as well as for the ternary systems, and also theoretically evaluated for the latter. The estimation of the compatibility degree of the above polymer pairs have been done by means of three criteria: (i) the sign of Db m , according to the traditional formalism developed by Krigbaum and Wall; (ii) the sign of a new de®ned Db ' m ; and (iii) the sign of D[Z] m . The two last criteria are proposed in this work and are based on treating the viscosity interaction parameter and the intrinsic viscosity as excess properties by similarity with those of real solutions. Both methods provide compatibility predictions in agreement with those made with the traditional one but they are much more simple in handling the calculations. Finally, the observed compatibility behaviour follows the order: (PES + PMMA)b b(PES + PVDF)>(PES + PS), in dimethylformamide as solvent, at least in the assayed composition range. #