Viscosity Interaction Parameter Research Articles

Viscometric Study of PC / PEG blends in THF solvent and Gamma-Rays Effect on the Viscosity of PC

In this research the intermolecular interaction between polycarbonate (PC) and polyethyleneglycol (PEG) in tetrahydrofuran (THF) solvent was studied, at 25˚C using a dilute solution viscometry method (DSV).
 The reduced viscosity and intrinsic viscosity and viscosity interaction parameter (b) were experimentally measured, we also discuss the compatility of a polymer mixture in terms of , and the effect of gamma-rays on the reduced viscosity and intrinsic viscosity and Huggins constant of (PC). The results show that the relation between and C is liner within C=(0.9-2)g/dl, and viscometric constant KH decreases with irradiation time while increases with Tirr.

The miscibility of collagen/hyaluronic acid/chitosan blends investigated in dilute solutions and solids

In the present study, the results from viscometric measurements, tensile tests and Fourier transform infrared spectroscopy (FTIR) of polymer blends containing collagen (Coll) and hyaluronic acid (HA) with and without chitosan (Ch) are presented.The viscosity interaction parameter of each polymer in 0.1mol·dm−3 CH3COOH/0.3mol·dm−3 NaCl solution for the collagen and 0.3mol·dm−3 NaCl or 0.1mol·dm−3 HCl solution for the hyaluronic acid and 0.1mol·dm−3 CH3COOH/0.3mol·dm−3 NaCl solution for the chitosan as well as the two-component blend systems and the ternary blend systems have been determined. These studies indicated that collagen/hyaluronic acid blends were miscible at any composition (Coll/HA: 80/20, 50/50, 20/80) in 0.1mol·dm−3 CH3COOH/0.3mol·dm−3 NaCl and 0.1mol·dm−3 HCl at 25°C. In the case of Coll/HA/Ch ternary blends, the polymeric components were partially miscible. The mechanical properties of films such as tensile strength and Young's modulus depend on the blend composition. Coll/HA blends possessed a tensile strength and Young's modulus of 16.3–57.6MPa and 1.0–1.9GPa, respectively. The addition of chitosan to the blend led to an increase in tensile strength by approximately 50%. The results of FTIR analysis suggested that there was the existence of intermolecular interactions between functional groups of polymers.

Chitosan blends containing hyaluronic acid and collagen. Compatibility behaviour

Degree of miscibility of chitosan (Ch) blends containing hyaluronic acid (HA) and collagen (Coll) was analysed by viscometric method, atomic force microscopy (AFM) and monitored by contact angle measurements. The viscosity interaction parameter of each polymer in 0.1mol⋅dm−3 CH3COOH/0.2mol⋅dm−3 NaCl solution for Ch and 0.5mol⋅dm−3 NaCl or 0.1mol⋅dm−3 HCl solution for HA and 0.1mol⋅dm−3 CH3COOH solution for Coll as well as the two-component blend systems and the ternary blend systems have been determined. These studies indicated that chitosan/hyaluronic acid blends were miscible at the weight fraction of chitosan wCh≥0.5 in 0.1mol⋅dm−3 CH3COOH/0.2mol⋅dm−3 NaCl and 0.1mol⋅dm−3 HCl at 25°C. In the case of ternary blends, the polymeric components showed miscibility with collagen at wColl<0.2. Moreover, it was found that the wettability of Ch/HA and Ch/HA/Coll blend films increased in comparison to the chitosan and collagen films. The study of blends by AFM showed a completely different morphology when compared with that of pure components as microdomains appeared as globular agglomerates containing more or less spherical particles instead of the independent microdomains observed in the native components, possibly as a consequence of interactions between polymers.

INFLUENCE OF THE INTERMOLECULAR INTERACTION ON PHYSICO-CHEMICAL PROPERTIES OF CHITOSAN/HYALURONIC ACID BLENDS

In the present study, the results of viscosity measurements in dilute solutions of chitosan (Ch) with hyaluronic acid (HA) are presented. Chitosan is blended with hyaluronic acid in aqueous 0.1M CH3COOH/0.2M NaCl and 0.3M NaCl respectively, or with the addition of HEPES. Viscosity measurements of dilute polymer solution were carried out in an Ubbelohde capillary viscometer. The intrinsic viscosity, [], and the viscosity interaction parameters, bm, have been determined for the binary (solvent/polymer) and ternary (solvent/polymer A/polymer B) systems. The homogeneity and morphology of chitosan blends were ascertained from the tapping-mode atomic force microscopy. The surface roughness of chitosan, hyaluronic acid and Ch/HA blended films was altered by mixing. The obtained results suggested that there was existence of the strong interactions between chitosan and hyaluronic acid.

Miscibility and physical properties of chitosan and polyacrylamide blends

Miscibility studies of chitosan/polyacrylamide (Ch/PAM) and chitosan/partially hydrolyzed polyacrylamide (Ch/HPAM) blends of different compositions were investigated using viscometric method. The intrinsic viscosity, ([η]), and the viscosity interaction parameters, (bm), have been determined for the binary (solvent/polymer) and ternary (solvent/polymer A/polymer B) systems. Degree of miscibility of these polymer blends was estimated on the basis of two criteria. These studies indicate that chitosan/polyacrylamide and chitosan/partially hydrolyzed polyacrylamide are miscible at any composition in 0.1mol·dm−3 CH3COOH+0.2mol·dm−3 NaCl at 25°C. The influence of blend composition on mechanical properties was also investigated in this study. Ch, PAM, HPAM and their blend films were prepared by casting technique. The mechanical properties such as ultimate tensile strength and Young modulus depend on the weight fraction of chitosan and were changed irregularly. The FTIR spectroscopy also supports the obtained results. The miscibility of polymer mixtures is related to the interactions between the functional groups of the polymeric components.

Transport behavior of aliphatic amino acids glycine/l-alanine/l-valine and hydroxyl amino acids l-serine/l-threonine in aqueous trilithium citrate solutions at different temperatures

Viscosities, η, of aliphatic amino acids glycine, l-alanine, and l-valine and hydroxyl amino acids l-serine and l-threonine in (0.0, 0.2, 0.4, and 0.6) mol·kg−1 aqueous trilithium citrate solutions at temperatures T=(288.15, 298.15, 308.15, and 318.15) K have been measured as a function of molality of amino acids. The Jones–Dole equation and transition state treatment have been used to obtain viscosity B-coefficient and viscosity interaction parameter, respectively. Enthalpy of viscous flow and entropy of viscous flow for amino acids in aqueous trilithium citrate solutions have also been calculated. The results have been discussed to interpret interactions between ions of amino acids and trilithium citrate.

VISCOMETRIC STUDIES OF CHITOSAN/POLYACRYLAMIDE MIXTURES

Polymer-polymer interactions and miscibility for chitosan (Ch) and partially hydrolysed polyacrylamide (HPAM) have been investigated using dilute solution viscosity. The intrinsic viscosity, [η], and the viscosity interaction parameters, bm, have been determined for the binary (solvent/polymer) and ternary (solvent/polymer A/polymer B) systems. Degree of miscibility of these polymer mixtures was estimated on the basis of two criteria. The final result depends on (i) the applied extrapolation method used for determination of the interaction parameters, (ii) the assumed miscibility criteria, and (iii) the blend composition.

Interactions of amino acids in aqueous triammonium citrate solutions at different temperatures: A viscometric approach

The viscosities, η of glycine (Gly), l-alanine (Ala), and l-valine (Val) with triammonium citrate have been measured as a function of temperature at T=(288.15, 298.15, 308.15 and 318.15) K. The change in viscosity of amino acids with increase in triammonium citrate concentration and temperature is attributed to amino acid–triammonium citrate interactions. The viscosity B-coefficients and viscosity interaction parameters obtained from the Jones–Dole equation and transition state theory respectively have been discussed to interpret interactions between ions of amino acids and triammonium citrate. Further, enthalpy of viscous flow and entropy of viscous flow have been determined.

Miscibility and physical properties of chitosan and silk fibroin mixtures

Miscibility investigations of chitosan (Ch) with silk fibroin (SF) mixtures with different weight percentage compositions (100/0, 80/20, 50/50, 20/80, 0/100) were studied using viscometric method. The viscosity interaction parameter of each polymer in 0.1mol·dm−3 solution as well as the ternary systems (polymer A, polymer B/solvent) has been determined. By comparing the experimental and ideal viscosity data it was clearly seen that the investigated system are miscible at the weight fraction of chitosan in the mixtures wCh≤0.5. Ch, SF and their mixture films were prepared by casting technique. The effect of mixture composition on mechanical and thermal properties was also investigated in this study. The mechanical properties such as ultimate tensile strength, Young modulus and tensile strain at break depend on the weight fraction of chitosan and were changed irregularly. The thermal properties of the film made of Ch/SF mixtures were similar to those of chitosan film.

Viscometric measurements of dipeptides of alanine in aqueous solutions of antibacterial drug ampicillin at different temperatures

The viscosities, ƞ of l-alanyl-l-alanine (Ala-Ala), l-alanyl-l-valine (Ala-Val), l-alanyl-l-leucine (Ala-Leu) with drug ampicillin (AMP) have been measured as a function of temperature at T=(305.15, 310.15 and 315.15) K. The change in viscosity of dipeptides with increase in AMP concentration and temperature is attributed to dipeptide–AMP interactions. The viscosity B-coefficients and viscosity interaction parameters obtained from Jones–Dole equation and transition state theory respectively have been discussed to interpret interactions between ions of dipeptides and ampicillin.

Viscometric Studies in Dilute Solution Mixtures of Chitosan and Microcrystalline Chitosan with Poly(vinyl alcohol)

The viscosity behavior of aqueous mixtures formed by a polyelectrolyte (A) and a neutral polymer (B), such as chitosan/poly(vinyl alcohol) (Ch/PVA) and microcrystalline chitosan/poly(vinyl alcohol) (MCCh/PVA), have been investigated at 25 °C. The intrinsic viscosity and the viscosity interaction parameter of each polymer in 0.1 mol·dm−3 CH3COOH/0.2 mol·dm−3 NaCl solution as well as the ternary systems (polymer A/polymer B/solvent) have been determined and have served for estimation of the miscibility of different polymer mixtures by means of the method of classical dilution. By comparing the experimental and ideal viscosity data it is clearly seen that the satisfaction of the miscibility criterion depends on the definition of the ideal parameter b_{text{m}}^{text{id}} . If the b_{text{m}}^{text{id}} parameter is defined according to the Krigbaum–Wall criterion and Garcia criterion, the investigated blends of Ch/PVA satisfy the miscibility criterion. In the case of MCCh/PVA blends, the polymeric components show poor miscibility. Additionally, the viscosity results show that the degree of miscibility depends on the molecular weight of chitosan and on the degree of PVA hydrolysis.Electronic supplementary materialThe online version of this article (doi:10.1007/s10953-013-0053-3) contains supplementary material, which is available to authorized users.

Viscosities of Glycine and l-Alanine in (0.2, 0.4, 0.6, and 0.8) mol·kg–1 Aqueous Dipotassium Hydrogen Phosphate Solutions at Different Temperatures

Viscosities, η, for glycine and l-alanine have been measured in (0.2, 0.4, 0.6, and 0.8) mol·kg–1 aqueous dipotassium hydrogen phosphate (DKHP) solutions at temperatures T = (288.15, 298.15, 308.15, and 318.15) K. The change in viscosity of amino acids with an increase in DKHP concentration and temperature is attributed to amino acid–DKHP interactions. The viscosity B-coefficients and viscosity interaction parameters obtained from the Jones–Dole equation and transition state theory, respectively, have been discussed to interpret interactions between ions of amino acids and dipotassium hydrogen phosphate.

Miscibility on blends of PVA and PFSA by viscometry

The intrinsic viscosity and viscometric interaction parameters of perfluorosulfonic acid (PFSA) and poly(vinyl alcohol) (PVA) were measured by dilute solution viscometry. The miscibility between PFSA and PVA was estimated by the criteria of ΔB and µ. The results indicated that PFSA and PVA were completely miscible for any weight fraction in aqueous solution.

The evaluation of miscibility of blends of poly(ether imide) (Ultem ®1000) and a copolyester of bisphenol-A with terephthalic and isophthalic acid (Ardel ®D-100) by viscosimetry

The intermolecular interactions and miscibility behavior between poly(ether imide) (Ultem ®1000) and a copolyester of bisphenol-A with a mixture of terephthalic and isophthalic acid (Ardel ®D-100) in compositions of 100/0, 80/20, 60/40, 40/60, 20/80 and 0/100 have been investigated in dilute solutions in chloroform. An Ubbelohde-type home-made viscometer was used to determine the specific viscosities of the blends in a constant temperature bath. Several viscosity interaction parameters used as the criteria of miscibility were determined from viscosity measurements. The parameters suggested that Ultem ®1000 and Ardel ®D-100 were miscible. The miscibility of the polymers was confirmed by the results of differential scanning calorimetry measurements.

The miscibility of poly(vinyl alcohol)/poly(N-vinylpyrrolidone) blends investigated in dilute solutions and solids

Poly(vinyl alcohol) (PVA) (polymer A) and poly(N-vinylpyrrolidone) (PVP) (polymer B) are known to form a thermodynamically miscible pair. In the present study the conclusion on miscibility of PVA/PVP solid blends, confirmed qualitatively (DMTA, FTIR) and quantitatively (DSC, χ AB = − 0.69 at 503 K) is compared with the miscibility investigations of PVA/PVP solution blends by the technique of dilute solution viscometry. The miscibility of the ternary (polymer A/ polymer B/ solvent) system is estimated on the basis of experimental and ideal values of the viscosity parameters k, b and [ η]. It is found that the conclusions on miscibility or nonmiscibility drawn from viscosity measurements in dilute solution blends depend: (i) on the applied extrapolation method used for the determination of the viscosity interaction parameters, (ii) on the assumed definition of the ideal values and (iii) on the thermodynamic quality of the solvent, which in the case of PVA depends on its degree of hydrolysis. Hence, viscometric investigations of dilute PVA/PVP solution blends have revealed that viscometry, widely used in the literature for estimation of polymer–polymer miscibility can not be recommended as a sole method to presume the miscibility of a polymer pair.

Miscibility and the specific interaction of polyhydroxybutyrate blended with polyvinylacetate and poly(vinyl acetate‐co‐vinyl alcohol) with some biological applications

AbstractBacterially produced polyhydroxybutyrate (PHB) polymer has a lot of potential as an application for environmentally degradable plastics. We aimed in this study to blend PHB with the semicrystalline polymers poly(vinyl acetate) (PVAc) and poly(vinyl acetate‐co‐vinyl alcohol) (PACA) to obtain material with better physical properties. We investigated compatibility over a wide composition range using different techniques. Viscosity measurements were used to study polymer–polymer miscibility in dilute solutions with chloroform as cosolvent. The data is discussed according to the viscosity interaction parameters, which are treated as excess properties by similarity with those of real solutions. Dielectric investigations were carried out at different frequencies ranging from 100 Hz to 50 kHz. The obtained data indicated that more than one relaxation mechanism was present, which were ascribed to the rotation of the main chain and its related motions. A glass‐transition temperature composition diagram, IR spectroscopy, and a morphological investigation were also used to give more information about the compatibility of such blends. The results of this study indicate that PHB/PVAc is semicompatible, whereas PHB/PACA is compatible at least in the assayed composition range of hydrolysis. We also extended the study to carry out some biological activity investigations, which were tested against the representative number of pathogenic organisms with the disk diffusion method. The different compositions of the investigated blend were biologically active when compared with the individual polymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2363–2374, 2002

Viscometric study on the compatibility of polymer–polymer mixtures in solution

Abstract The viscosity behaviour of mixtures formed by two uncharged polymers in dilute solution has been studied at 25°C. 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 fluoride) (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 Δbm, according to the traditional formalism developed by Krigbaum and Wall; (ii) the sign of a new defined Δb′m; and (iii) the sign of Δ[η]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)≫(PES+PVDF)>(PES+PS), in dimethylformamide as solvent, at least in the assayed composition range.

Viscometric study of mixtures of neutral and charged polymers in aqueous solution

The viscosity behaviour of aqueous mixtures formed by a polyelectrolyte ( A) and a neutral polymer ( B) such as polystyrene sulfonate (PSS)-polyvinylpyrrolidone (PVP) and polylysine (PLL)-PVP has been studied at 25 °C. The intrinsic viscosity and viscosity interaction parameter of each polymer in water have been determined and have served us to estimate the compatibility of the different mixtures according to two different methodologies: (i) mixtures of two polymers in water as solvent and (ii) mixtures of either polymer A or B in a solvent formed by either polymer B or A in water (“polymer solvent method”). By comparing the experimental and theoretical viscosity data it is clearly seen that: mixtures of both polymers in water do not depict any kind of thermodynamic interaction; whereas mixtures formed by a polyelectrolyte in water + neutral polymer as solvent exhibit incompatibility and, on the other hand, ternary systems formed by the neutral polymer (PVP) in a polyelectrolyte solvent show compatibility. The viscosity results show that the compatibility behaviour depends on the concentration ratio of both polymers in the mixture. Finally, an attempt to establish reference systems has been made.

Viscometric behaviour of polymer blends based on poly (vinylidene fluoride)

The viscosity behaviour of dilute dimethylformamide solutions of poly(vinylidene fluoride)-poly (methyl methacrylate) and poly(vinylidene fluoride)-polystyrene has been studied at 25°C. The polymer concentration ranges are such that neither phase separation nor microgel formation occurs, although we are very close to theta conditions. The intrinsic viscosity and viscosity interaction parameter of the ternary mixtures have been calculated. The estimation of the compatibility of the above polymer pairs has been studied based on: a) specific viscosities; b) viscosity interaction parameters, according to Krigbaum and Wall formalism, and c) viscosity interaction parameters of a system formed by a dilute probe polymer in the presence of a matrix polymer and a small molecule solvent.

Solution Viscosity of Linear Flexible High Polymers and Viscosity Interaction Parameter

Abstract Several methods based on the Huggins equation are available for studying the behavior of linear flexible high polymers in the Newtonian region of concentrated solutions. The work of Simha and Zakin has attracted our attention to further investigation since it suffers from limitations in the type of solvent and the molecular weight range of the polymer suggested for study. It was observed that a suitable modification of the Huggins equation would widen the scope of the original method. An alternative method for determining the incipient concentration c0 where the intermolecular attraction and the repulsion just balance each other, is also suggested.