Interaction between polyvinylpyrrolidone and surfactant from viscosimetric data

The intrinsic viscosities of solutions of polyvinylpyrrolidone (PVP) in water-sodium dodecyl sulphate have been measured, for four different molecular weights of PVP, and different concentrations of sodium dodecyl sulphate at temperatures between 20 and 35°C. The exponent a of the Mark-Houwink-Sakurada equation has been determined, and the values of the short range interaction parameter K_θ, and expansion factor α_η derived. Above a certain concentration the sodium dodecyl sulphate is adsorbed on the polymer by means of hydrophobic attractions, and the consequent repulsion between anionic heads provokes expansion of the macromolecule.     

Viscosity‐molecular weight relationship for cellulose solutions in either NMMO monohydrate or cuen

The intrinsic viscosities, [η], of nine cellulose samples, with molar masses from 50 × 10³ to 1 390 × 10³ were determined in the solvents NMMO*H₂O (N‐methyl morpholin N‐oxide hydrate) at 80°C and in cuen (copper II‐ethlenediamine) at 25°C. The evaluation of these results with respect to the Kuhn–Mark–Houwink relations shows that the data for NMMO*H₂O fall on the usual straight line in the double logarithmic plots only for M ≤ 158 10³; the corresponding [η]/M relation reads log ([η]/mL g⁻¹) = –1.465 + 0.735 log M. Beyond that molar mass [η] remains almost constant up to M ≈ 10⁶ and increases again thereafter. In contrast to NMMO*H₂O the cellulose solutions in cuen behave normal and the Kuhn–Mark–Houwink relation reads log ([η]/mL g⁻¹) = −1.185 + 0.735 log M. Possible reasons for the dissimilarities of the behavior of cellulose in these two solvents are being discussed. The comparison of three different methods for the determination of [η] from viscosity measurements at different polymer concentrations, c, demonstrates the advantages of plotting the natural logarithm of the relative viscosities as a function of c. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Miscibility of polystyrene with poly(ethylene oxide) and poly(ethylene glycol)

The intrinsic viscosity of polystyrene–poly(ethylene oxide) (PS–PEO) and PS–poly(ethylene glycol) (PEG) blends have been measured in benzene as a function of blend composition for various molecular weights of PEO and PEG at 303.15 K. The compatibility of polymer pairs in solution were determined on the basis of the interaction parameter term, Δb, and the difference between the experimental and theoretical weight-average intrinsic viscosities of the two polymers, Δ[η]. The theoretical weight-average intrinsic viscosities were calculated by interpolation of the individual intrinsic viscosities of the blend components. The compatibility data based on [η] determined by a single specific viscosity measurement, as a quick method for the determination of the intrinsic viscosity, were compared with that obtained from [η] determined via the Huggins equation. The effect of molecular weights of the blend components and the polymer structure on the extent of compatibility was studied. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1471–1482, 1998     

Comparison of various solvents for determination of intrinsic viscosity and viscometric constants for cellulose

Different solvents used to determine the intrinsic viscosity and the viscometic constants, a and K, published in the literature for cellulose, were compared. The various parameters affecting the viscometric constants were also evaluated. The main conclusions obtained from the experimental data available in the literature are that (1) the intrinsic viscosities in various solvents are ordered as follows: [η]_LiCl/DMAc > [η]_NH3/NH4SCN ≥ [η]_FeTNa > [η]_CED > [η]_Cadoxen > [η]_Cuoxam; (2) the reported intrinsic viscosities and molecular weights for cellulose are lower than the true value due to degradation of cellulose in the solvents; (3) the rate of degradation was the smallest in LiCl/DMAc and NH₃/NH₄SCN, moderate in cadoexn and FeTNa, and the highest in CED and cuoxam; (4) the plot of log K versus exponent a was linear and inversely related; (5) the curve was used for estimation of the constant K for cellulose in a solvent (NH3/NH4SCN) with a known exponent a; and (6) among various reported solvents, LiCl/DMAc and NH₃/NH₄SCN are advantageous over other solvents because of a complete dissolution of the polymer with a negligible reduction in its intrinsic viscosity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2189–2193, 2002     

Interpretation of intrinsic viscosity/temperature data for solutions of poly(phenyl acrylate) and poly(ethylene oxide)

Measured intrinsic viscosities ([η]) at several temperatures (T) within the interval 280–350 K have been found to increase with T for solutions of poly(phenyl acrylate) (PPA) in ethyl lactate. A decrease of [η] with T was observed for aqueous solutions of poly(ethylene oxide) (PEO) at several temperatures within the range 276–358 K. The results have been treated on the basis of eight excluded volume theories, among which the best consistency was afforded by those of Kurata-Stockmayer-Roig, Fixman, and Stockmayer (Padé). These yielded values of ?3.4 × 10^?3 to ?4.7 × 10^?3 deg^?1 and ?0.9 × 10^?3 to ?2.4 × 10^?3 deg^?1 for the temperatur coefficient of the unperturbed dimensions of PPA and PEO, respectively. The derived θ-temperatures were 287 K as the upper critical solution temperature for PPA in ethyl lactate and 365–382 K as the lower critical solution temperature for aqueous PEO.     

Physicochemical studies of globular proteins—Bovine serum albumin,egg albumin,and lysozyme—In some aqueous iodide salts solutions of IA group and cetyltrimethyl ammonium bromide systems

Densities (ρ, kg m^?3), and viscosities (η, 0.1 kg m^?1 s^?1) of Bovine Serum Albumin (BSA), Egg Albumin, and Lysozyme in aqueous iodide salts of lithium, sodium, and potassium, along with cationic surfactant‐cetyltrimethyl ammonium bromide (CTAB) were measured at a temperature of 303.15 K. The 0.0010–0.0018 g %, w/v of each protein at an interval of 0.0002 mol L^?1 in 0.2, 0.4, and 0.8 millimol L^?1 of salt and CTAB are studied. Data are used for apparent molar volumes (V_?, 10^?6 m³ mol^?1) and intrinsic viscosities ([η], dL kg^?1), respectively. Data are regressed and extrapolated to zero concentrations for ρ⁰, η⁰, and limiting values and S_d, S_η and S_V corresponding slopes for protein–salt structural interactions. With size of cations, the densities decrease as CTAB > LiI > NaI > KI and increase with salts concentrations, with salts the densities are as Lysozyme > BSA > Egg Albumin, viscosities and V_? as BSA > Egg–Albumin > Lysozyme. The ρ and η values with CTAB higher and [η] are lower and converse at around 0.4 mmol L^?1 salt and is effective for greater stability of proteins. The [η] in CTAB are higher than other salts and decreases with size of cations with stronger intermolecular forces. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Solution dynamics of the dextran/crosslinking agent systems

The interaction of some selective Cl‐ and N‐containing functional crosslinking agents such as epichlorohydrin (ECH), N,N′‐methylenebisacrylamide (MBAM), and bifunctional agents such as glutaraldehyde (GA) and glycidylmethacrylate (GM) with dextran (Dx) in aqueous solutions were studied by viscometric and spectroscopic methods. The dynamic viscosities of Dx‐crosslinker aqueous solutions have been measured at physiological temperature, 37°C and in the concentration range of 0.22–0.4 g/dL. Concentration of crosslinkers were kept constant at 0.001–0.35 mol/L. Viscosity behavior of the solutions was interpreted using the Huggins and Kraemer equations. Moreover, the interaction between hydroxyl groups of the Dx with crosslinkers in aqueous solutions, structure properties was also confirmed thereby use of Raman and FTIR spectroscopy. For the Dx/crosslinker systems, the decreasing order of interaction was determined as ECH > GA > MBAM > GM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Aggregate formation in poly(ethylene oxide) solutions

Static light scattering and viscosity measurements were performed on different molecular weight poly (ethylene oxide) to see the formation of aggregates in its dilute solutions. Viscosity measurements were carried out for PEO samples in water and methanol at 20–45°C and in chloroform at 20–30°C. Using Huggin's equation, the viscosity plots showed distinct upward curvature indicating the presence of aggregates in both PEO/H₂O and PEO/CH₃OH solutions The [η] values for PEO/H₂O and PEO/CH₃OH system were 2–4 times as large as observed for other linear flexible polymers in good solvents thus showing extensive coil swelling/aggregation. This is also apparent from the exponent a values of the Mark–Houwink–Sakurada equation. Light Scattering results using Zimm method showed that aggregation occurred in low molecular weight samples; however, in higher molecular weight samples there was a little evidence for aggregation both in water and methanol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2578–2583, 2006     

Properties of aqueous salt solutions of polyvinylpyrrolidone. I. Viscosity characteristics

The properties of dilute solutions of polyvinylpyrrolidone (PVP) in aqueous salt solutions have been studied by measurements of intrinsic viscosity [η] in theta and nontheta solvents. Intrinsic viscosities of the polymer solutions were observed to decrease upon addition of a variety of inorganic salts (phosphates, monohydrogen phosphates, carbonates, sulfates, and dihydrogen phosphates). Values of the Huggins constant, k_H, were found to be higher than 0.35 for PVP in pure water at 298 K, whereas in salt solutions they varied from 0.85 to 1.28 in nontheta solvents. Kraemer's constant, k_K, was also determined and k_H-k_K was calculated as 0.78 for PVP in pure water and for aqueous salt solutions of PVP, k_H-k_K = 0.61 at 298 K. k_H values were also higher than the predicted range of 0.5–0.7, and k_H-k_K values were noted to be 0.73 in theta solvents. © 1996 John Wiley & Sons, Inc.     

Physical characterization of a) a series of ethyl esters and b) a series of ethanoate esters

Physical characterizations of (1) the ethyl esters of the naturally occurring C₆−C₁₈ saturated fat acids and (2) the ethanoate esters of the saturated alcohols corresponding to the above acids have been made. They are a) refractive indices at 20°, 25°, 30°, 35°, and 40°C., b) densities and viscosities at 35°, 50°, 65°, 80°, and 95° C., and c) boiling points at several pressures. The physical characteristics exhibited by the two series of esters are quite similar. However the actual values obtained for the ethanoate esters are slightly higher than those obtained for the corresponding ethyl esters.     

Effects of denaturing agents on the molecular association of dextran. I. Aqueous solutions

Molecular association of aqueous dextran solutions have been investigated by viscosimetric measurements. Intrinsic viscosities of different concentrations of aqueous solutions of dextran with a variety of denaturing agents have been determined. Intrinsic viscosity numbers and Huggins constants of dextran solutions decreased with the addition of denaturing agents. The reducing effect of denaturing agents on the intrinsic viscosities and Huggins constants decreased in the order guanidinium sulfate > guanidinium carbonate > guanidinium chloride > thiourea > urea. The effect of temperature on the intrinsic viscosities of dextran and dextran denaturing agent solutions have also been investigated. A small change in the intrinsic viscosity values was observed for dextran in 1M of guanidinium carbonate and sulfate solutions with the increase of the temperature from 25 to 40 °C. Aqueous dextran solutions, however, showed a significant decrease in the intrinsic viscosities in the same temperature range. © 1995 John Wiley & Sons, Inc.     

Effect of phenol derivatives on molecular dimensions of poly(N‐vinyl‐2‐pyrrolidone) in aqueous solution

The unperturbed dimensions and thermodynamic parameters of poly(N‐vinyl‐2‐pyrrolidone) (PVP) were studied in aqueous solutions in the presence of certain phenolic cosolutes (phenol, catechol, hydroquinone, resorcinol, and phloroglucinol). The intrinsic viscosities at 25°C and the θ temperature, linear and thermodynamic expansions, and root mean square end to end distances were evaluated for the system that was employed. The sequence was obtained due to the effectiveness of the cosolutes in the order of phloroglucinol > resorcinol > hydroquinone > catechol > phenol. The effects of these cosolutes on the main thermodynamic parameters were reported to be due to the number and position of hydroxyl groups present. The thermodynamic interaction parameter was also evaluated and the enthalpic and entropic contributions were verified. The condition required for the θ temperature to correspond to a Flory interaction parameter of 0.5 was well provided, yielding a θ temperature of almost 0.5 for the system under study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 473–477, 2002; DOI 10.1002/app.10047     

Effect of temperature on viscosity of amylose

Viscosity parameters were obtained for maize maylose (molecular weight of 107,000) in 1N KOH at 25, 30, 35, and 40°C. Intrinsic viscosity continuously decreased and Huggins' constant k' continuously increased with increasing temperature. The temperature dependence of intrinsic viscosity, d[η]/dT, was ?2.12 × 10^?2/°C.     

Synthesis of copolymers of N,N-dimethyl acrylamide and methacrylate esters and their surface tensions

A systematic study was made on the preparation of N,N-dimethylacrylamide (NDMA)/ methacrylic ester statistical copolymers. The methacrylic ester comonomers used in the copolymerizations were ethyl, n-butyl, n-hexyl, n-octyl, n-dodecyl, n-hexadecyl, and n-octadecyl methacrylates. It was found that the NDMA copolymers could be prepared in three molecular weight regions: 1.0 × 10⁴, 2.0 × 10⁵, and greater than 1.0 × 10⁶ ([η] in water at 30°C of 0.1, 0.6, and greater than 1.5 dL/g, respectively). The molecular weights of the copolymers were dependent on the solvent employed in the polymerizations and on the presence of a chain transfer agent (t-dodecyl mercaptan). All copolymer compositional analyses were made by 400 MHz ¹H-NMR spectroscopy. The NDMA/methacrylic ester copolymers decreased the surface tension of water in the order: C₄ = C₆ > C₈ > C₁₂ > C₁₆ > C₂ = C₁₈ > P(NDMA), lowest surface tension (35 dyn/cm) to highest surface tension (59 dyn/cm).     

Viscosity–molecular weight relationship for aminopropyl‐terminated poly(dimethylsiloxane)

Aminopropyl‐terminated poly(dimethylsiloxane) (ATPS) with different molecular weights was prepared by base‐catalyzed equilibration of octamethylcyclotetrasiloxane and 1,3‐bis(3‐aminopropyl)‐1,1,3,3‐tetramethyldisiloxane with different ratios. Their number‐average molecular weights (M_n) were determined by end–group analysis, and intrinsic viscosity ([η]) in toluene was measured with a Ubbelohde viscometer. A relationship between M_n and [η] was obtained for ATPS. For 1.0 × 10⁴ < M_n < 6.0 × 10⁴, it was in accord with [η]_{toluene,25°C} = 5.26 × 10^?2 M_n^0.587. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 975–978, 2001     

Viscosity/molecular‐weight relationship for γ‐(2,3‐dihydroxypropoxy)propyl‐terminated poly(dimethylsiloxane)s

A series of γ‐(2,3‐dihydroxypropoxy)propyl‐terminated poly(dimethylsiloxane) (DHT‐PDMS) samples with different molecular weights were prepared through the acid‐catalyzed equilibrium copolymerization of octamethylcyclotetrasiloxane and 1,3‐bis[γ‐(2,3‐dihydroxypropoxy)propyl]tetramethyldisiloxane. The intrinsic viscosity in toluene ([η]_toluene) and the number‐average molecular weight (M_n) were determined with an Ubbelohde viscometer and ¹H‐NMR spectra, respectively. In this way, the relationship between [η]_toluene and M_n was established. For 2.0 × 10⁴ < M_n < 4.0 × 10⁴, [η]_{toluene,25°C} was 1.874M_n ^0.323. The solution behavior of DHT‐PDMS was also investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1759–1762, 2004     

Synthesis of copolymers of N,N-dimethyl acrylamide and methacrylate esters and their surface tensions

A systematic study of the preparation of N,N-dimethylacrylamide (NDMA)/methacrylic ester statistical copolymers was conducted. The methacrylic ester comonomers used in the copolymerizations were ethyl, n-butyl, n-hexyl, n-octyl, n-dodecyl, n-hexadecyl, and n-octadecyl methacrylates. It was found that the NDMA copolymers could be prepared in three molecular weight regions 1.0 × 10⁴, 2.0 × 10⁵, and greater than 1.0 × 10⁶ ([η] in water at 30°C of 0.1, 0.6, and greater than 1.5 dL/g, respectively). The molecular weights of the copolymers were dependent on the solvent employed in the polymerizations and on the presence of chain transfer agent (t-dodecyl mercaptan). All copolymer compositional analyses were made by 400 MH_z ¹H-NMR spectroscopy. The NDMA/methacrylic ester copolymers decreased the surface tension of water in the order: C₄ = C₆ > C₈ > C₁₂ > C₁₆ > C₂ = C₁₈ > P(NDMA), from lowest surface tension (35 dyn/cm) to highest surface tension (59 dyn/cm).     

Intrinsic viscosity–number average molecular weight relationship for poly(1,4‐butylene adipate) diol

The relationship between number average molecular weight (M_n) and intrinsic viscosity ([η]) was studied for poly(1,4‐butylene adipate) diol (PBAD) in tetrahydrofuran, toluene, and ethyl acetate at 25°C. Thus, a series of PBAD samples were prepared by polymerization between 1,6‐adipic acid and 1,4‐butanediol. The values of M_n for the samples were determined by end‐group analysis as well as by ebulliometry, and the average difference of M_n between the two analysis ways was about 2.69%. The Mark–Houwink–Sakurada equations for PBAD were obtained to relate [η] with M_n in the range of 1900–10,000. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Viscosity studies of some polyamides dissolved in mixed solvents (cosolvents)

The solubility of poly (octamethylene sebacamide) (POS), poly (octamethylene terephthalamide) (POT) and poly (octamethylene tetrachloroterephthalamide) (POTC1), in $\text{m-}\text{cresol}\text{cyclohexane}$ mixtures, a cosolvent system, has been studied by measuring the intrinsic viscosity [η], at 25°C. The intrinsic viscosities of POT, POS and POTC1 in various solvent/non-solvent mixtures are higher than the corresponding intrinsic viscosities in the pure solvent m-cresol. The POT and POTC1 polyamides exhibit a sharp increase in [η] values compared with the corresponding small increase in the POS polyamide. The POTC1 polyamide presents a true cosolvency effect in $\text{m-}\text{cresol}\text{cyclohexane}$ mixtures; m-cresol and cyclohexane are non-solvents for this polyamide. The cosolvent behaviour is discussed in terms of the most energetically favourable interactions. The aromatic ring in POT and POTC1 would expand the chain, would favour a better packing between neighbouring solvent molecules and would favour the selective adsorption in the cosolvent system.     

Automated batch characterization of polymer solutions by static light scattering and viscometry

Using a programmable mixing pump, light scattering flow chamber, refractive index detector, and single capillary viscometer, the batch (unfractionated) characterization of polymers in solution has been automated. Three different schemes to produce polymer concentration gradients were used, and values for weight average mass M_w, root mean square radius of gyration 〈S²〉^1/2, second virial coefficient A₂, and intrinsic viscosity [η] were determined for a broad distribution sample of poly(vinyl pyrrolidone) (PVP) and a narrow fraction of poly(ethylene oxide) (PEO). High concentration experiments on the PVP also allowed determination of the third virial coefficient A₃. The method has several advantages over traditional manual methods in terms of accuracy, sample preparation, and amount of labor required. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2359–2368, 1999