Showing papers in "Journal of Applied Polymer Science in 1971"
TL;DR: In this article, an empirical equation which correlates the relative viscosities of suspensions (or relative moduli of filled polymeric materials) as a function of solids concentrations and particle size distributions is proposed.
Abstract: The dependence of the viscosities of highly concentrated suspensions on solids concentrations and particle size distributions is investigated by using an orifice viscometer. Based on the extensive amount of data on pertinent systems, an empirical equation which correlates the relative viscosities of suspensions (or relative moduli of filled polymeric materials) as a function of solids concentrations and particle size distributions is proposed. The equation has a constant which characterizes size distributions of spherical particles and can be determined experimentally without measuring viscosities. For uniform-size spherical particles, it reduces to the well-known Einstein equation at dilute solids concentrations.
707 citations
TL;DR: In this paper, an attempt has been made to rationalize the variables in the preparation procedure of Loeb-Sourirajan-type reverse-osmosis membranes and the porosity of the membrane has been ascribed to the relative rates of water entering and solvent leaving the cast film.
Abstract: An attempt has been made to rationalize the variables in the preparation procedure of Loeb-Sourirajan-type reverse-osmosis membranes. The quaternary phase diagram of the system cellulose acetate–acetone–formamide–water was determined and has proved a useful tool in the discussion of membrane structures and properties. A mechanism based on differences in the precipitation rate of the polymer during the membrane formation process has been suggested to explain the observed asymmetry in the membrane structure. The porosity of the membrane has been ascribed to the relative rates of water entering and solvent leaving the cast film. The effects of the casting solution composition, the evaporation time, the wash bath temperature, and the annealing procedure have been studied. X-Ray diffraction and electron microscopy were used to supplement flux and retention data of membranes made from a cellulose acetate–formamide–acetone casting solution.
143 citations
TL;DR: In this article, an idealized model for flexible foam in tension is developed, which includes large deformations and cell structure orientation before and after deformation, and it is predicted that two quantities affect the initial modulus of an unoriented foam: the density and a cell structure parameter.
Abstract: An idealized model for flexible foam in tension is developed. The model includes large deformations and cell structure orientation before and after deformation. It is predicted that two quantities affect the initial modulus of an unoriented foam: the density and a cell structure parameter. Data for latex foam show that the model correctly predicts the initial tensile modulus. The model also predicts that cell structure orientation is a reasonable method for achieving a desired modulus without altering the density.
96 citations
TL;DR: In this paper, it is suggested that the bumps are caused by the migration of low molecular weight degradation products to charged areas of the polymer surface, and that most of the oxidized layer was eliminated from the polyethylene surface by solvent dipping and that degraded products contained a substantial proportion of CH2 groups.
Abstract: Corona treatment of low-density polyethylene in oxygen or oxygen-containing gases produced bumps on the surface, while treatment in nitrogen, hydrogen, argon, or helium caused no detectable surface change. Bumps made by an oxygen corona increased in size with time and temperature of the treatment. The bumps were removed when a treated polymer sheet was dipped into solvents such as CCl4, ethanol, or 0.2% aqueous NaOH. Infrared analysis indicated that most of the oxidized layer was eliminated from the polymer surface by solvent dipping and that the degraded products contained a substantial proportion of CH2 groups. It is suggested that the bumps are caused by the migration of low molecular weight degradation products to charged areas of the polymer surface.
83 citations
TL;DR: In this paper, the results show that solute separation in reverse osmosis is governed by the hydrogen bonding ability of the organic molecule when it is essentially undissociated and by electrostatic repulsion of ions when the molecule is partially or completely dissociated.
Abstract: Reverse osmosis data of 32 different alcohols and phenols and 22 different monocarboxylic acids in aqueous solutions in the concentration range 0.0001 to 0.007M (∼100 ppm in most cases) have been studied using porous cellulose acetate membranes at 250 psig. Solute separation data for alcohols and phenols are correlated with Δνs (shift in the OH band maximum in the IR spectra), and those for the monocarboxylic acids are correlated with Ka (dissociation constant) and the degree of dissociation of the molecule. Solute separation decreases with increase in Δνs for alcohols and phenols. The solute separation-versus-Ka correlation for acids passes through a minimum, and solute separation always increases with increase in the degree of dissociation. The separation data are also correlated with Taft and Hammett numbers which represent the effect of the substituent group on the polar effect of the molecule. The product rate data show a general tendency to decrease with decrease in solute separation in all cases. These results show that, with respect to the systems considered, solute separation in reverse osmosis is governed by the hydrogen bonding ability of the organic molecule when it is essentially undissociated and by electrostatic repulsion of ions when the molecule is partially or completely dissociated. Thus, data on Δνs for alcohols and phenols, and those on Ka and degree of dissociation for monocarboxylic acids, constitute precise physicochemical criteria for reverse osmosis separation of the above solutes in aqueous solutions using porous cellulose acetate membranes.
83 citations
TL;DR: In this article, a detailed discussion is given on the state of dispersion of two incompatible polymer systems in the molten state, by presenting pictures of the microstructure of the extrudate samples.
Abstract: A study is carried out for characterizing two-phase systems of molten polymers by their viscous and elastic properties. The two-phase systems chosen for study are blends of polystyrene and polypropylene, and blends of polystyrene and high-density polyethylene. For the study, measurements of wall normal stresses are made by use of a capillary melt rheometer described in part I of this series. The concept of the “exit pressure” is used to determine the elastic properties of the two-phase polymer systems. The present study shows anomalous viscous and elastic properties of two-phase systems, which are difficult to predict from knowing the viscous and elastic properties of their individual components. A detailed discussion is given on the state of dispersion of two incompatible polymer systems in the molten state, by presenting pictures of the microstructure of the extrudate samples. The state of dispersion appears to vary depending on the blending ratio, extrusion temperature, melt viscosities of individual components, and blending method.
83 citations
TL;DR: In this article, the effect of an aqueous environment on the tensile properties of Kapton polyimide film has been investigated, and it was shown that immersion in distilled water at 25° to 100°C for time periods ranging from one hour to several hundred hours resulted in a decrease in the ultimate tensile strength of the polymer from 23 ksi to approximately 14 ksi, and a corresponding decrease in elongation to failure from 38% to approximately 5%.
Abstract: The effect of an aqueous environment on the tensile properties of Kapton polyimide film has been investigated. Immersion of specimens in distilled water at 25° to 100°C for time periods ranging from one hour to several hundred hours resulted in a decrease in the ultimate tensile strength of the polymer from 23 ksi to approximately 14 ksi, and a corresponding decrease in elongation to failure from 38% to approximately 5%. The kinetics of this decrease in mechanical properties are second order and yield an activation energy of approximately 15.6 kcal/mole. The reaction is slightly dependent on pH in the range 2.0 to 12.0, but is highly dependent on the pH in the range 0.4 to 2.0. The decrease in mechanical properties at pH 2.0 to 6.0 appears to be due to hydrolysis of either uncyclized amic acid linkages or diamide functional groups present in the polyimide, whereas that at pH below 2.0 is probably the result of hydrolysis of both imide and amide bonds. Prolonged reflux of the polyimide in water resulted in the extraction of a water-soluble, amide-containing material.
81 citations
TL;DR: The flow properties of polymer melts containing fillers of various shapes and sizes have been examined in this paper, and the modulus enhancement for randomly distributed filler is equal to the melt viscosity enhancement under medium shear stress conditions (104 Nm−2) in simple shear flow or in oscillatory shear fluid flow.
Abstract: The flow properties of polymer melts containing fillers of various shapes and sizes have been examined. If there is no failure of either the filler or polymer in the solid state, then the modulus enhancement for randomly distributed filler is equal to the melt viscosity enhancement under medium shear stress conditions (104 Nm−2) in simple shear flow or in oscillatory shear flow. Submicron-size fillers, in particular, can form weak structures in the melt that greatly increase the low shear rate viscosity without changing the modulus of the solid proportionately. The highly pseudo-plastic nature of polymer melts at shear stresses of 106 Nm−2 means that, even without orientation of filler particles toward the flow direction, the viscosity enhancement is less than at lower shear stresses.
79 citations
TL;DR: In this article, color motion pictures have been made of the flow of low-density polyethylene, polystyrene, and isotactic polypropylene at 180°C in the reservoir approach to a capillary extrusion rheometer.
Abstract: Color motion pictures have been made of the flow of low-density polyethylene, polystyrene, and isotactic polypropylene at 180°C in the reservoir approach to a capillary extrusion rheometer Detailed observations of the variation of flow patterns with extrusion rate were made At low flow rates, essentially radial flow into the capillary entrance was observed in all polymers With increasing flow rate, the included entrance angle α for the polyethylene and polystyrene decreased from 180°C and a “wine glass” structured velocity field was observed with stagnant circulating regions in the corners and the melt channeling in through the wine glass to the capillary entrance The angle α was related to entrance pressure drop Δpe and capillary wall shear stress σw data through the semilogarithmic equation
where α is in degrees; Δpe/σw is interpreted as a Weissenberg number The breakdown of stable laminar flow of the melts in the reservoir and the distortion of extrudates was observed These phenomena seemed to be initiated by the formation of a spiralling motion in the reservoir
76 citations
TL;DR: In this article, it was shown that the ceiling flux in reverse osmosis is equal to the pervaporation flux in highly swollen polymer membranes. But the proposed ceiling flux was not shown to correlate with the permeation flux for such membranes.
Abstract: The pressure-driven transport of liquids employed in reverse osmosis has been shown to occur by a solution-diffusion mechanism in highly swollen polymer membranes A theory based on this mechanism was successfully used earlier to correlate permeation fluxes for such membranes Positive confirmation of this theory is provided here by direct measurement of the proposed concentration gradient A study of the temperature dependence of the liquid diffusion coefficient in the polymer membrane has provided additional evidence of a hydrodynamic regime of diffusion in highly swollen membranes It is also shown that the proposed ceiling flux in reverse osmosis is equal to the pervaporation flux
71 citations
TL;DR: In this article, a low-density polyethylene sheet is treated in a corona discharge and subsequently pressed to a similarly treated sheet at 45°C, the bond formed is much stronger than that between similarly pressed but untreated sheets.
Abstract: If a low-density polyethylene sheet is treated in a corona discharge and subsequently pressed to a similarly treated sheet at 45°C, the bond formed is much stronger than that between similarly pressed but untreated sheets. Several series of observations have indicated that this enhanced autohesion is not due to surface oxidation or to surface crosslinking (CASING). Evidence is presented that the effect may be related to some type of electret formation induced in the polymer sheet by the corona discharge.
TL;DR: A resin containing a high proportion of low molecular weight constituents has been prepared and separated into fractions; four of these are new compounds.
Abstract: Furfuryl alcohol resins contain a broad spectrum of compounds. The distribution of these compounds in a given resin varies with the manufacturing conditions. A resin containing a high proportion of low molecular weight constituents has been prepared and separated into fractions. Twelve compounds were separated from the resin; four of these are new compounds. The lower molecular weight constituents can be arranged into four major classes: polyfurfuryl alcohols, polyfurfuryl furans, methyl-substituted polyfurfuryl furans, and polyfurfuryl ethers.
TL;DR: In this article, numerical methods for the solution of Tung's axial dispersion equation have been developed and comprehensively evaluated and can be applied where the instrumental spreading function is unsymmetrical and nonuniform.
Abstract: Numerical methods for the solution of Tung's axial dispersion equation have been developed and comprehensively evaluated. These methods are general and can be applied where the instrumental spreading function is unsymmetrical and nonuniform. Computation times required are comparable to those of the method of Chang and Huang being about 10 sec per case on the CDC6400 computer. Memory requirements are minimal and this should permit their use with minicomputers for data acquisition and processing.
TL;DR: In this article, two water-soluble synthetic polymers and several polysaccharides were compared for friction reduction effectiveness during increased exposure to turbulent flow in a 0.117 × 41.0 cm fine bore tube at a constant solvent wall shear stress of 4200 dynes/cm2 and wall speed of 4 × 105 sec−1.
Abstract: Two water-soluble synthetic polymers and several polysaccharides were compared for friction reduction effectiveness during increased exposure to turbulent flow. Solutions were passed through a 0.117 × 41.0 cm fine bore tube at a constant solvent wall shear stress of 4200 dynes/cm2 and wall shear rate of 4 × 105 sec−1. After one pass through the tube, greatest friction reduction at low polymer concentrations was in the order poly(ethylene oxide) > polyacrylamide > bacterial polysaccharide from Xanthomonas campestris > guar gum. As a result of mechanical degradation, after 40 passes of 40 ppm solutions, friction reduction effectiveness was in the order polyacrylamide > polysaccharide from Xanthomonas campestris > poly(ethylene oxide) > guar gum. Degradation curves, the effect of concentration on degradation, and boundary layer and pipe flow applications are discussed.
TL;DR: A typical gas chromatogram of the volatile pyrolysis products of untreated α-cellulose contains 39 peaks; however, mass spectral data indicate that at least 59 compounds, with molecular weights less than about 150, are present as discussed by the authors.
Abstract: A typical gas chromatogram of the volatile pyrolysis products of untreated α-cellulose contains 39 peaks; however, mass spectral data indicate that at least 59 compounds, with molecular weights less than about 150, are present. A total of 37 compounds have been identified, 13 of which have not been previously reported. Most of the newly identified compounds contain a benzene ring, indicating that these compounds may be products of reactions between initial volatiles. A comparison of the products generated in the temperature range of 330°–440°C indicates that the formation of pyrolysis products is essential independent of temperature. Comparisons of the chromatograms obtained for untreated levoglucosan and cellulose indicate that most of the decomposition of cellulose probably forms levoglucosan which then decomposes to yield the observed pyrolysis products. In addition, the products of flame retardant-treated levoglucosan are essentially the same as those of cellulose with the same retardant treatment. This suggests that the retardants act on the levoglucosan formed in the decomposition of the cellulose rather than on the cellulose directly.
TL;DR: In this article, a composite reverse-osmosis membrane was developed for seawater desalination having a 400-A semipermeable barrier, which demonstrated improved flux stability at high pressures over modified membranes currently used to desalinate brackish water.
Abstract: A composite reverse-osmosis membrane has been developed for seawater desalination having a 400-A semipermeable barrier. The membrane is prepared by directly forming a very thin film of a polymer, generally cellulose triacetate, upon the finely porous surface of a supporting membrane. The composite membrane, capable of desalinating seawater in a single pass, has demonstrated improved flux stability at high pressures over modified membranes currently used to desalinate brackish water.
TL;DR: In this paper, a simple trigonometric function was derived to relate linear deformation due to swelling to the angle which the direction of its measurement makes with the fiber direction, and the validity of the derivation was demonstrated experimentally.
Abstract: The solvent swelling of unidirectional rubber–fiber composites was studied. The amount of matrix swelling was constrained to the extent that would be predicted from the thermodynamic theories of elasticity and polymer–solvent interaction. The geometry of swelling was found to be orthotropic in nature. A simple trigonometric function was derived to relate linear deformation due to swelling to the angle which the direction of its measurement makes with the fiber direction. The validity of the derivation was demonstrated experimentally. Considering swelling to be the imposition of tensile forces of equal magnitude in all directions, and considering a swelling-induced linear deformation to be analogous to a tensile compliance, a simple set of relationships between elastic parameters and their direction of measurement was derived:
where Eθ, Gθ, vθ, and ηθ are Young's modulus, shear modulus, Poisson's ratio, and the shear coupling ratio measured in a longitudinal transverse plane at an angle with the fiber direction, respectively, and EL, GLT, and θLT are the longitudinal Young's modulus, the longitudinal transverse shear modulus, and the longitudinal transverse Poisson ratio, respectively. Further simplifying the case of combined transverse isotropy and special orthotropy was the conclusion that 1/GLT = 1/ET + (1 + 2vLT)/EL. The relationships for G and E were experimentally demonstrated.
TL;DR: In this paper, a method of obtaining films of aromatic heterocyclic ladder polymers has been found which circumvents casting from high-boiling acidic solvents.
Abstract: A new method of obtaining films of aromatic heterocyclic ladder polymers has been found which circumvents casting from high-boiling acidic solvents. The BBL ladder polymer has been formed into tough, durable films by collecting suspensions of the polymer obtained from acid reprecipitations upon a fritted glass funnel. After drying, the polymer can be removed as film, with thickness dependent upon the amount of material used. Such a film has a tensile strength of 9,600 lb/in.2 as compared to a tensile strength of 16,000 lb/in.2 obtained from the same polymer when cast from methanesulfonic acid solution.
TL;DR: In this article, the polymerization rate of styrene in an electrodeless glow discharge from styrene vapor and a mixture of gas (H2, He, A, and N2) was investigated.
Abstract: The polymerization (polymer deposition) rate of styrene in an electrodeless glow discharge from styrene vapor and a mixture of styrene vapor and gas (H2, He, A, and N2) was investigated. The rate of polymerization, R, was found to be independent of the discharge power. The rate of polymerization of the pure monomer was found to be proportional to the square of monomer pressure pM. The addition of gas increased the rate of polymerization depending upon the partial pressure of the gas, px, and R can be generally expressed by R = a[pM]2{1 + b[px]}. The value of b is dependent of the type of gas and follows the order of N2, > A > He > H2. The distribution of polymer deposition was found to be nearly independent of the partial pressure of the gas and of the discharge power with N2 and H2 as plasma gas; however, with He and A, the distribution is highly dependent on the partial pressure of the gas and on the discharge power. The study strongly suggests that polymerization occurs in the vapor phase and that the growing polymer radicals deposit on the surface of the discharge vessel, yielding highly crosslinked polymer deposition.
TL;DR: In this article, three starch-polyacrylonitrile (S-PAN) graft copolymers containing ratios of 1:1.90, 1: 1.16, and 1:0.64 were prepared by graft polymerization of acrylitrile onto gelatinized starch.
Abstract: Three starch–polyacrylonitrile (S–PAN) graft copolymers containing ratios of S:PAN of 1:1.90, 1:1.16, and 1:0.64 were prepared by graft polymerization of acrylonitrile onto gelatinized starch. A fourth graft, made from granular starch, had an S:PAN ratio of 1:2.16. These grafts were hydrolyzed in potassium hydroxide under various conditions to give a series of products with varying amounts of carboxylic acid and amide groups. Maximum conversion of nitrile to carboxyl was 65%. Aqueous dispersions of the hydrolyzed S–PAN's at pH 7–8.5 were viscous, and, in general, their viscosities reflected the amount of PAN add-on, with the highest add-on giving the highest viscosity. Plots of the η/C versus C show that hydrolyzed S–PAN's from gelatinized starch behave as normal polyelectrolytes on dilution to low concentration but that S–PAN from granular starch does not.
TL;DR: In this article, the authors showed that increasing the thickness of epoxy joints with either tetraethylenepentamine (TEPA) or hexahydrophthalic anhydride (HHPA) was associated with a marked increase in macroroughness, and showed that an upper limit of joint thickness and hence toughness occurred because very thick joints could not be produced because residual stresses developed during cooling from the curing temperature caused the latter to separate at the interface.
Abstract: Increasing joint thickness was shown to increase the toughness of epoxy joints hardened with either tetraethylenepentamine (TEPA) or hexahydrophthalic anhydride (HHPA) The increased toughness was associated with a marked increase in macroroughness An upper limit of joint thickness and hence toughness occurred because very thick joints could not be produced Residual stresses developed during cooling from the curing temperature caused the latter to separate at the interface Stress corrosion cracking resistance was also found to depend on bond thickness For the TEPA-hardened system, bond thickness had only a minor influence for thicknesses up to 25 mils; and for the HHPA-hardened system, this persisted to bond thickness of 50 mils Further increases in bond thickness for both systems caused an abrupt rise in resistance to stress corrosion cracking
TL;DR: In this paper, the tensile and compressive properties of polystyrene bead (PSB) foams at room temperature for strain rates from 10−3 to 105 min−1 can be represented as nearly linearly increasing functions of modulus or stress versus the logarithm of the strain rate.
Abstract: Tensile and compressive properties of polystyrene bead (PSB) foams at room temperature for strain rates from 10−3 to 105 min−1 can be represented as nearly linearly increasing functions of modulus or stress versus the logarithm of the strain rate. The shear modulus and tensile data, including failure properties, on 0.054 g/cc PSB foam at various temperatures and strain rates can be represented by master curves of log (stress or modulus) versus log (reduced strain rate). These master curves are formed by a time and temperature superposition method, wherein data at one temperature are superposed on data at another temperature by a shift along the log (strain rate) axis. These time–temperature shift factors are calculated using a form of the Arrhenius equation.
TL;DR: In this paper, the significance of the damping peak associated with the rubber phase of the polymer has probably been generalized to too great an extent, and two examples of polymer groupings are given to illustrate the need for caution in attaching significance to the dynamic mechanical properties of polymers.
Abstract: Dynamic mechanical properties have been used as the basis for some important conclusions with regards to the physical properties of rubber-modified high-impact polymers. This paper attempts to show that conclusions of this type should be limited to fairly narrow groupings of polymers. Since the size, shape, and position on the temperature scale of a damping peak are influenced by composition, morphology, and method of polymer preparation, the significance of the damping peak associated with the rubber phase of the polymer has probably been generalized to too great an extent. Two examples of polymer groupings are given to illustrate the need for caution in attaching significance to the dynamic mechanical properties of polymers. Also given are two fairly narrow polymer groupings to show to what extent dynamic mechanical properties can be used for a correlation with impact strength and rubber concentration.
TL;DR: In this paper, the kinetics of continuous emulsion polymerization of styrene were studied theoretically on the basis of the authors' batch reaction model, and a new reaction model was proposed for continuous operation.
Abstract: The kinetics of continuous emulsion polymerization of styrene were studied theoretically on the basis of the authors' batch reaction model, and a new reaction model was proposed for continuous operation. The validity of the model was tested by experiments conducted with stirred tank reactors in series. The characteristics of the first reactor used to generate polymer particles were studied in particular detail. It was found that there was an optimum residence time for the first reactor, the value of which was quantitatively predictable from the operating variables. The most suitable combinations of several types of reactors for continuous emulsion polymerization are also discussed.
TL;DR: In this paper, two experimental studies of the melt spinning of fibers have been carried out using low-density polyethylene and polystyrene, and the relationship between the fiber kinematics and drawdown force was studied using the concept of a non-Newtonian elongational viscosity and a nonlinear integral theory of viscoelastic fluids.
Abstract: Two experimental studies of the melt spinning of fibers have been carried out using low-density polyethylene and polystyrene First, isothermal spinning experiments were carried out and the relationship between the fiber kinematics and drawdown force was studied The data were correlated by using the following two methods: (1) the concept of a non-Newtonian elongational viscosity and (2) a nonlinear integral theory of viscoelastic fluids In the second experiment, the spinline temperature profile of a monofilament fiber being pulled down from a spinneret through stagnant air was measured and the heat transfer coefficient computed A correlation between the local Nusselt number and a fiber Reynolds number was obtained An integral boundary layer analysis of forced convection heat transfer from a descending fiber was carried out
TL;DR: In this article, low molecular weight components of both an acid-polymerized and a γ-alumina polymerized furfuryl alcohol polymer were separated by gas chromatography utilizing a Porapak type P-S column packing.
Abstract: Low molecular weight components of both an acid-polymerized and a γ-alumina polymerized furfuryl alcohol polymer were separated by gas chromatography utilizing a Porapak type P-S column packing. The identities of the separated polymer components were established by infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance analysis. Volatile constituents found to be common to both furfuryl alcohol resin types were: furfuryl alcohol, water, difurylmethane, difurfuryl ether, and 2,5-difurfurylfuran. Also, 5-furfurylfurfuryl alcohol was found to be present only in the acid-polymerized resin, and 4-furfuryl-2-pentenoic acid γ-lactone was a constituent only of the γ-alumina-polymerized resin. Contrary to expectation, no esters of levulinic acid were found among the low molecular weight components of the γ-alumina-polymerized furfuryl alcohol polymer.
TL;DR: In this paper, the influence of molecular weight distribution and long chain branching on both viscous and elastic properties of molten polymers, using a capillary rheometer, was investigated.
Abstract: Experimental work has been carried out to investigate the influence of molecular weight distribution and long chain branching on both viscous and elastic properties of molten polymers, using a capillary rheometer, as described in a recent paper by Han. The materials used for the study are three high-density polyethylene samples of widely different molecular weight distributions and a low-density polyethylene containing much long-chain branching. For the analysis of the experimental data, and to obtain the information on the melt elasticity, the concept of the exit pressure recently advanced by Han is used. The study shows that the sample containing long-chain branching is much more elastic than the samples containing little or no long-chain branching, and that the broader the molecular weight distribution of the material, the more elastic the material is. These findings are in conformity with those reported in the literature. Also studied were blends of two high-density polyethylenes having widely different molecular weight distributions. The results of the blends systems show a maximum in melt viscosity as well as in elasticity for a certain blending ratio. The results of the present study may be of considerable interest to those who are concerned with modifying the structure of polymer and also with determining optimum processing conditions.
TL;DR: In this paper, it was shown that the solvent power of an organic liquid for a given polymer can be characterized by two parameters, δh and χH, where χh is the hydrogen-bonding solubility parameter of the liquid, and φ is a term which takes account of the dispersion and polar interactions between the liquid and the polymer and of the effects due to temperature and molecular size of the mixture.
Abstract: From thermodynamic considerations based on associated solution models and from the Hansen's three-dimensional solubility parameter concept, it is found that the solvent power of an organic liquid for a given polymer can be characterized by two parameters, δh and χH, where δh is the hydrogen-bonding solubility parameter of the liquid, and χH is a term which takes account of the dispersion and polar interactions between the liquid and the polymer and of the effects due to temperature and molecular size of the liquid. It is also found that Hansen's solubility sphere for the polymer can be represented as a solubility circle in the proposed χH−δh plane. The proposed approach is applied successfully to polymer–plasticizer systems.
TL;DR: In this article, the degradation of poly(ethylene oxide) and polyacrylamide during turbulent flow of dilute solutions (1 to 50 g/kl) was measured in terms of friction reducing effectiveness.
Abstract: A simple, fixed-head flow device was used to characterize drag reduction by polymers in water. Using a parallel flow of water as a reference system, the Reynolds numbers ranged from 8600 to 12,000. The degradation of poly(ethylene oxide) and polyacrylamide during turbulent flow of dilute solutions (1 to 50 g/kl) was measured in terms of friction-reducing effectiveness. Poly(ethylene oxide) decreases in effectiveness more rapidly than polyacrylamide in a recycling test.