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1996. Ronay, M., “Determination of the dynamic surface tension of inks from the capillary instability of jets,” J. Colloid and Interface Science, 66, 55-67, (Aug 1978).

A remarkable agreement between Weber's linear analysis and experiment makes it possible to determine the dynamic surface tension of viscous liquids from the growth rate of axisymmetric disturbances on excited capillary jets. The method is very accurate and can be used to determine the surface tension at as short as 10−4 sec surface age. Aqueous glycerol solution and inks developed for inkjet printing were used as test liquids in the experiments. While a dye base ink showed time-dependent surface tension, the surface tension of inks which were colloid suspensions of small pigment particles and contained surfactant micelles equalled their equilibrium value at 10−4 sec surface age. In the tentative explanation of this phenomenon, the dynamic equilibrium between surfactant molecules in solution and in micelles was substituted for long-range surfactant transport by diffusion. A result of this assumption is that surface tension in nonequilibrium states depends only on the composition of the surface layer.

2367. Lutzmann, H.H., and P.D. Frayer, “Method of bonding sheets in air by alternating current corona discharge and apparatus for same,” U.S. Patent 4096013, Jun 1978.

Two or more chemically dissimilar and non-compatible films may be bonded together to form a composite sheet by simultaneously subjecting them to high voltage electric corona discharge of selected intensity continuously through a critical region of mutual contact of the films. The critical region begins at the point at which the film surfaces to be bonded are not in contact with one another and extends at least to the point where all the films to be bonded are in mutual contact with their adjacent films.

A preferred film suitable for use as a wrapping material and obtained by the process of the invention comprises at least one layer of a polyolefin film and at least one layer of a film containing an acrylonitrile polymer.

1997. Gifford, W.A., “The effect of contact angle on ring tensiometry,” J. Colloid and Interface Science, 64, 588-591, (May 1978).

50. Carley, J.F., and P.T. Kitze, “Corona-discharge treatment of polyethylene films, I. Experimental work and physical effects,” Polymer Engineering and Science, 18, 326-334, (Mar 1978).

Corona treatment of films, mainly polyethylene, was studied at commercial levels in a small continuous treater. Degree of treatment was characterized by measuring polar and dispersion components of surface energy, ASTM Wipe and ASTM Adhesion Ratio (“peel adhesion”). The chief factors studied were corona current, applied frequency, web speed, dielectric thickness and air-gap thickness between electrode and film. Other factors less intensively investigated were type of film, film additives, aging time after treatment, humidity and corona atmosphere. The polar component of surface energy, γ, is the key to understanding the changes in adhesive behavior of the films during treatment. We found that, for the equipment used, γ is accurately given by the equation

where D = dielectric thick ness and G = air gap, both in mils; S = web speed, ft/min; I = corona current, ma, and γ is in dyne-cm/cm2. A similarly structured equation describes ASTM Wipe. Using measured surface-energy components for the pressure-sensitive tape used in the peel adhesion test, it was possible to calculate an adhesion interaction for each film on which peel adhesion was measured and to show that it closely correlates with peel strength. Humidity changes in the moderate-humidity range, number of electrodes used and corona frequency had little effect on properties. Slip additives inhibited development of adhesion until treatment levels became high; adhesion properties gradually diminished upon aging of films stored at ambient conditions.

2333. Severn, I.D., and S.L. Burring, “The wetting properties of lithographic printing surfaces,” in Wetting, Spreading and Adhesion, J.F. Padday, ed., 403-421, Academic Press, 1978.

2332. Elliott, G.E.P., T.A. Elliott, S.M. Rowan, and I.D. Severn, “The influence of the surface coating on the wettability of nylon 6 fibres,” in Wetting, Spreading and Adhesion, J.F. Padday, ed., 391-402, Academic Press, 1978.

1545. Tietje, A., “Corona treating systems for coater-laminators,” in TAPPI 1978 Conference Proceedings, 173+, TAPPI Press, 1978.

1544. Ristey, W.J., et al, “Degradation and surface oxidation of PE...,” in TAPPI 1978 Conference Proceedings, 267+, TAPPI Press, 1978.

1543. Spell, H.L., et al, “Surface analysis of corona treated PE...,” in TAPPI 1978 Conference Proceedings, 283+, TAPPI Press, 1978.

1530. Fowkes, F.M., and M.A. Mostafa, “Acid-base interactions in polymer adsorption,” Industrial & Engineering Chemistry Product Research & Development, 17, 3-7, (1978).

Most polymers and inorganic materials have acidic or basic sites (or both) which can interact to enhance wettability, adsorption, charge-transfer, and adhesion. These interactions, termed “polar” in the past, are independent of dipole moments and occur only when one material has acid groups which can interact with basic groups of the other material. the presence of a third component (solvent, plasticizer, penetrant, etc.) can interfere with adsorption, charge-transfer, or adhesion if the third component has strong enough acid-base interactions with either or both components. Water, a weak acid and a weak base, tends to weaken adhesion of polymers to inorganic materials but not when these have strong acid-base interactions.

A quantitative approach to predicting the enthalpy ΔHab of acid-base interactions between polymers and inorganic surfaces is presented based on determining the E and C constants of Drago's correlation for polymers and inorganic surfaces. Preliminary E and C constants are presented for polymethylmethacrylate, for chlorinated polyvinylchloride, for silica surfaces and for iron oxide surfaces.

1324. Neumann, A.W., “Contact angles,” in Wetting, Spreading and Adhesion, J.F. Padday, ed., 3-35, Academic Press, 1978.

934. Clark, D.T., A. Dilks, and D. Shuttleworth, “The application of plasmas to the synthesis and surface modification of polymers,” in Polymer Surfaces, Clark, D.T., and W.J. Feast, eds., 185-211, John Wiley & Sons, 1978.

917. Schonhorn, H., “Surface modification of polymers for adhesive bonding,” in Polymer Surfaces, Clark, D.T., and W.J. Feast, eds., 213-233, John Wiley & Sons, 1978.

657. Wu, S., “Interfacial energy, structure and adhesion between polymers,” in Polymer Blends, Vol. 1, Paul, D.R., and S. Newman, eds., Academic Press, 1978.

Most small-molecule organic liquids are mutually miscible and their mixtures do not form stable interfaces. Polymers are, however, usually immiscible and their mixtures form multiphase structures with stable interfaces. The dispersion, morphology, and adhesion of the component phases are affected by the interfacial energies, which thereby play an important role in determining the mechanical properties of a multiphase polymer blend. This chapter discusses interfacial energy, structure, and adhesion between polymers as related to the properties of polymer blends. It provides an overview of surface tension and interfacial tension, and discusses various theories of interfacial tension such as Antonoff's rule, theory of Good and Girifalco, theory of fractional polarity, and lattice theories. The interfacial tension varies more slowly with temperature than the surface tension and arises mainly from the disparity between the polarities of two phases. The extent of non-polar (dispersion) interaction between the two phases does not vary greatly from system to system but that of polar interactions can vary greatly. The polar interactions largely determine the magnitude of the interfacial tension. The polarity of a polymer can be calculated from the interfacial tension between the polymer and a non-polar polymer such as polyethylene, which can be regarded to be completely nonpolar. Thus, if the interfacial tension of a polar polymer against polyethylene is known, the polarity of the polar polymer can be calculated. Adhesion is the bonding or joining of dissimilar bodies, while autohesion or cohesion refers to joining of identical bodies. Several adhesion theories have been proposed. They have been a subject of much controversy. Most theories deal with the formation of the adhesive bond. The chapter reviews various factors affecting the formation and the fracture of adhesive bonds.

588. Vavruch, I., “On the determination of the factor between cohesive energy density and surface tension,” J. Colloid and Interface Science, 63, 600+, (1978).

558. Schreiber, H.P., and F. Ewane-Ebele, “On the surface tension and its temperature variation in film-forming polymers,” J. Adhesion, 9, 175+, (1978).

A thermal gradient bar has been used for convenient measurements of γc and dγc/dT in complex polymers used as film-formers. The technique yields both γc and its temperature variation in one experimental sequence well suited for rapid, routine applications. Surface tension data have been obtained for a styrene-acrylic terpolymer, and these have also been used to characterize the compatibility of external plasticizers for the polymer. The surface tension approach has shown that glyceryl dibenzoate, though compatible with the polymer at temperatures above ∼70°C becomes incompatible at use temperatures, and exudes to the polymer film surface. Measurements of moisture sensitivity in plasticized polymer samples have confirmed the incompatibility and illustrated one of the applications to which the gradient bar and its data generation potential may be put.

543. Padmanabhan, S., “Surfactants and wettability (graduate thesis),” Univ. of Rhode Island, 1978.

542. Padday, J.F., ed., Wetting, Spreading, and Adhesion, Academic Press, 1978.

507. Ko, Y.C., “Characterization of hydrophobic/hydrophilic polymeric surfaces by contact angle measurements (MS thesis),” Univ. of Washington, 1978.

442. Clark, D.T., and A. Dilks, “ESCA applied to polymers, XVIII. RF glow discharge modification of polymers in helium, neon, argon, and krypton,” J. Polymer Science Part A: Polymer Chemistry, 16, 911-936, (1978).

The crosslinking of an ethylene–tetrafluoroethylene copolymer by exposure to a variety of inert gas plasmas, excited by an inductively coupled radiofrequency (RF) field, has been studied. The rates for direct and radiative energy-transfer processes are determined within the framework of a kinetic model of the system and are shown to have a strong dependence on the sustaining gas, as do the average depths of penetration of the ions and metastable species. Helium is found to be the most efficient gas for the crosslinking of the outermost few monolayers whereas the crosslinking of the subsurface and bulk polymer is best effected by neon. Madelung charge potential calculations have been performed to simulate the experimentally determined x-ray photoelectron spectroscopy (ESCA) spectra to elucidate several features of the mechanisms involved.

80. Dick, F., “How surface tension affects flexographic printing,” in FTA Annual Forum, 1978, Flexographic Technical Association, 1978.

62. Clark, D.T., and W.J. Feast, eds., Polymer Surfaces, John Wiley & Sons, 1978.

9. Andrews, E.H., and N.E. King, “Surface energetics and adhesion,” in Polymer Surfaces, 47-63, John Wiley & Sons, 1978.

1824. Baum, E.A., T.J. Lewis, and R. Toomer, “Further observations on the decay of surface potential of corona charged polyethylene films,” J. Physics D: Applied Physics, 10, 2525-2531, (Dec 1977).

For the authors' previous work see ibid., vol.10, p.487 (1977). Further measurements are reported on the decay of surface potential of negative corona charged polyethylene films and on the crossover effect reported earlier by Ieda and co-workers (1967). It is shown that when the duration of charging is short ( approximately 25 ms) the subsequent decay curves of surface potential are well-behaved and do not exhibit the crossover effect even though the initial surface fields are high. Experiments are also reported in which an air stream is directed along the surface of the films while corona charging. This also removes the crossover effect and is in agreement with results reported in which an air stream is directed along the surface of the films while corona charging. This also removes the crossover effect and is in agreement with results reported by Okumura (1976) for polystyrene-hexamethacrylate. It is concluded that excited molecules as well as photons produced in the corona discharge play an important role in inducing charge from surface states to enter the bulk of the polymer where they are much more mobile. This leads to rapid decay of surface potential at higher initial surface fields and the crossover effect is then observed.

2307. Kolbe, A., and P. Dinter, “Corona apparatus,” U.S. Patent 4059497, Nov 1977.

A corona apparatus comprising at least one roller electrode assembly, a supporting surface acting as a counter electrode, and a generator for generating an alternating current voltage for said electrode assembly characterized in that the roller electrode assembly comprises: a central shaft, an electrode, means for mounting said electrode to said shaft, a tube, means for mounting said tube for rotation about said shaft, said electrode contained within said tube, means for electrically connecting said electrode to said generator and means for supporting said shaft whereby said tube is positioned adjacent to said counter electrode.

1998. Johnson, R.E., Jr., R.H. Dettre, andD.A. Brandreth, “Dynamic contact angles and contact angle hysteresis,” J. Colloid and Interface Science, 62, 205-212, (Nov 1977).

Contact angles have been measured as a function of the three-phase-boundary velocity. Large velocity effects observed with other techniques were not seen using the plate method. It is possible to relate the dependence of contact angles on velocity to surface heterogeneity.

2366. Tagaki, T., “Corona producing a planographic printing sheet,” U.S. Patent 4036136, Jul 1977.

A method for producing a plate or sheet useful in planographic printing which is characterized in that the surface of an oleophilic body comprising oleophilic resin is subjected to a corona discharge treatment to form a hydrophilic layer on said surface, and that said method can be carried out without difficulty at a low cost and the reproducibility of the printing plate thereby produced is excellent.

2027. Ewane-Ebele, F., and H.P. Schreiber, “Measurement and use of surface tension data in film-forming polymers,” J. Oil and Colour Chemists Association, 60, 249-255, (Jul 1977).

Describes a method of measuring the critical surface tension of film forming polymers and the effect of temperature on the surface tension. The method gave reliable results for polyethylene, polystyrene, and polymethyl methacrylate. Changes in polymer properties due to aging can be monitored by the method, and the effect of glass transition temperatures and the effect of plasticizers in a styrene/acrylic copolymer were also studied.

2365. Beatty, T.R., and H. Vourlis, “Heat-treated, corona-treated polymer bodies and a process for producing them,” U.S. Patent 4029876, Jun 1977.

Polymer films, such as polypropylene and polyethylene, having improved surface adhesion characteristics and produced by subjecting conventional polymer films to a heat treatment followed by a corona treatment at an energy density-to-film surface of at least 9 watt-minutes/ft.2.

1828. Tamai, Y., T. Matsunaga, and K. Horiuchi, “Surface energy analysis of several organic polymers: Comparision of the two-liquid-contact-angle method with the one-liquid-contact-angle method,” J. Colloid and Interface Science, 60, 112-116, (Jun 1977).

The dispersion force component of surface tension γSd and the nondispersive interaction energy at the water/solid interface (or the nondispersive work of adhesion) ISWn were evaluated for poly-(tetrafluoroethylene) (PTFE), poly(vinylchloride) (PVC) and poly(methylmethacrylate) (PMMA) by the analysis of the contact angles of water drops in hydrocarbon (the two-liquid-contact-angle method). The results were compared with those obtained by the one-liquid-contact-angle method with α-bromonaphthalene and methylene iodide as probe liquids, which is the method usually adopted. The values of γSd from the two-liquid method were considerably larger than those from the one-liquid method, whereas their high sensitivity to error in the measurement of contact angles was taken into account. This discrepancy may be attributed to the neglect of the surface pressure π in the one-liquid method and the π values of the liquids used on the sample solids were calculated.

1999. Davis, B.W., “Estimation of surface free energies of polymeric materials,” J. Colloid and Interface Science, 59, 420-428, (May 1977).

A new method has been developed for calculating surface free energies of polymeric materials using a simplified solution to the Fowler equation and polarizabilities and diamagnetic susceptibilities for polymer constituent groups. Comparison of this new method with estimates from group parachors, contact angle measurements, or extrapolation of data for melts indicates generally good agreement among the different methods. Discussions are also included on the effect of limited rotation on dipolar interactions and on the proper application of Good and Girifalco's method for estimating surface free energies of solids.

1796. Hu, P., and A.W. Adamson, “Adsorption and contact angle studies II: Water and organic substances on polished polytetrafluoroethylene,” J. Colloid and Interface Science, 59, 605-614, (May 1977).

Ellipsometrically determined adsorption isotherms are reported for water, bromobenzene, nitro-methane, benzene, amyl, butyl, propyl, and ethyl alcohols, carbon tetrachloride, n-octane, and n-hexane on a polished polytetrafluoroethylene surface. These are nonwetting systems, and contact angles were also measured. In addition, isotherms were determined for two wetting systems, carbon tetrachloride on oxide-coated stainless steel and n-hexane on oxide-coated chromium-plated glass. For most of the nonwetting cases, the film pressure of the adsorbed film was not negligible, and should not not be omitted in semiempirical treatments of contact angle. The isotherms may be fitted by a previously proposed potential-distortion model, the choice of parameters also giving the observed contact angle. Alternatively, the isotherms are found to be segments of a single characteristic isotherm of the Polanyi type and thus obey a corresponding state principle. This characteristic isotherm for nonwetting systems does not fit the data for the two wetting cases, and the possibility is discussed that in the nonwetting cases the adsorbed state consists of bulk-like liquid in the form of micropatches or lenses rather than as a film of uniform thickness.

2000. Ryley, D.J., and B.H. Khoshaim, “A new method of determining the contact angle made by a sessile drop upon a horizontal surface (sessile drop contact angle),” J. Colloid and Interface Science, 59, 243-251, (Apr 1977).

The contact angle may be measured by magnifying the projected image of a sessile drop, assuming the profile is elliptical, and finding the Cartesian coordinates of selected points on the profile. By selecting groups of three such points the mean equation to the outline can be determined and thus the tangent at the observed point of contact. The method was tested using water drops on various steel surfaces and using mercury on glass. Results showed generally satisfactory agreement with those obtained using the tilting plate method and also with those obtained by other investigators who have employed analytical methods to define the drop shape. If the sessile drop shape is assumed to be a part-oblate spheroid, a minimum free-energy analysis illuminates several experimentally observed features of its shape.

1974. Neumann, A.W., and A.V. Rapacchietta, “Comments to J.R. Huntsberger: Surface chemistry and adhesion - a review of some fundamentals,” J. Adhesion, 9, 87-91, (1977).

1973. Huntsberger, J.R., “Reply to A.W. Neumann,” J. Adhesion, 9, 93-94, (1977).

1814. Matsunaga, T.J., “Surface free energy analysis of polymers and its relation to surface composition,” J. Applied Polymer Science, 21, 2847-2854, (1977).

The dispersion force component of surface free energy, γ, and the nondispersive interaction free energy between solid and water, I, were determined by the two-liquid contact-angle method, i.e., by the measurement of contact angles of water drops on plain solids in hydrocarbon, for commercialy available organic polymers such as nylons, halogenated vinyl polymers, polyesters, etc. A method to estimate the I values from the knowledge of the polymer composition is also proposed, on the basis of the assumption of the spherical monomer unit and the sum of interactions between functional groups and water molecules at the surface.

1748. Yasuda, H., “Modification of polymers by plasma treatment and by plasma polymerization,” Radiation Physics and Chemistry, 9, 805-817, (1977).

Plasma chemistry of polymers may be categorized into two major types of reactions as (1) surface reaction of polymers and (2) polymerization of monomers by plasma. So far as these two types of reactions are concerned, plasma is very similar to other ionizing radiation, such as ..gamma.. radiation, x radiation, UV radiation, and high-energy electron beams, which can (1) initiate polymerization of certain monomers, and create free radicals on polymer exposed, which lead to (2) crosslinking of the polymer and/or (3) degradation of the polymer, or can be further utilized as the initiation sites of (4) graft copolymerization. The characteristic features of plasma are (1) the radiation effect is limited to the surface, and the depth of the layer affected by the plasma is much smaller than that by other more penetrating radiation, and (2) the intensity at the surface is generally stronger than that by the more penetrating radiations. Therefore, plasma treatment provides an ideal means of modifying surface properties of polymers. Examples are presented and discussed.

1518. Schonhorn, H., et al, “Surface modification of polymers and practical adhesion,” Polymer Engineering and Science, 17, 440-449, (1977).

The, nature of polymer surfaces has received increasing attention as the use of these materials, in a variety of forms, increases yearly. Modifications of polymer surfaces for adhesion, friction, and diffusion oriented appiications have necessitated a careful analysis of the surfade region morphology (surface physics) and chemical properties of the surface layer (surface chemistry). The behavior of composite structures has involved the discipline of classical fracture mechanics. The orientation of polymeric species or additives which migrate to the interface may modify the wetting characteristics and, most certainly, the frictional properties in addition to the diffusion of penetrant species beyond the boundary layer. The above topics are discussed within the framework of recent analytical and theoretical developments in surface science. The findings of these recent studies have facilitated many exciting technological advances.

1349. Dukes, W.A., and A.J. Kinloch, “Preparing low-energy surfaces for bonding,” in Developments in Adhesives, Vol. 1, W.C. Wake, ed., Applied Science Publishers, 1977.

562. Schultz, J., K. Tsutsumi, and J.B. Donnet, “Surface properties of high-energy solids, II. Determination of the nondispersive component of the surface free energy of mica and its energy of adhesion to polar liquids,” J. Colloid and Interface Science, 59, 277-282, (1977).

A method of determining the polar term of the adhesion energy of several liquids to a high-energy solid, ISLP, has been developed, based on the measurement of the contact angle of water on a solid in a liquid medium. The ISLP values for mica are found to be a linear function of the square root of the polar term of the surface free energy of liquids. This finding agrees with the suggestion that the polar term of the energy of adhesion may be represented by the geometric mean of the polar term of the surface free energy of a solid and a liquid. The slope of the straight line provides the value of γSP = 90 ergs/cm2 for the polar term of the surface free energy of mica. The results were compared with those obtained by a cleavage method and also discussed in terms of each component of the surface free energy of mica. The present method is useful for the determination of the polar part of the energy of adhesion of a high-energy solid to liquids, and its surface free energy.

 

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