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  • 1
    Electronic Resource
    Electronic Resource
    Chemical derivatization as a mean to improve contact angle goniometry of chemically heterogenous surfaces (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 699-709 
    Details
    ISSN: 0887-624X
    Keywords: contact angle goniometry ; chemical derivatization ; plasma treatment ; polyethylene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma-oxidized polyethylene (O-PE) was derivatized with various chemicals and the advancing and receding contact angles with water, formamide, and tricresylphosphate were measured. The contact angles were used to evaluate the surface free energy (SFE) components in terms of the Lifshitz-van der Waals-acid base (LW-AB) model. The derivatization was directed to couple alkyl chains to carbonyl, hydroxyl, and carboxyl groups generated on the surface of O-PE. Carbonyl groups were treated with hydrazine and then reacted with dodecanoyl chloride. Hydroxyl groups were first reacted with reactive dicarboxylic acid dichlorides or cyanuric chloride, respectively, and then with alkylamines because the direct bonding of long-chain alkyl carboxylic acid chlorides proceeds slowly and is, therefore, completed by surface restructuring. Carboxyl groups were chlorinated and in a second step reacted with alkylamines. The bonding of C12-alkyl chains can be sensitively detected by the LW part of the SFE. Concerning the receding contact angles, it is pointed out that the carbonyl groups are present on the surface in a higher concentration than hydroxyl and carboxyl groups. The combination of contact angle goniometry (CAG) and chemical derivatization reactions supplies semiquantitative information about functional groups in the uppermost surface layer. In this way, a major shortcoming of CAG can be overcome. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320408
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  • 2
    Electronic Resource
    Electronic Resource
    Vacuum-ultraviolet induced oxidation of the polymers polyethylene and polypropylene (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2013-2025 
    Details
    ISSN: 0887-624X
    Keywords: vacuum ultraviolet oxidation ; polyethylene ; polypropylene ; plasma-polymer interaction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The emission from low-pressure microwave plasmas in the vacuum-ultraviolet (VUV) region (λ 〈 200 nm) was investigated in order to use these plasmas as light sources for the study of the VUV photochemistry of polyethylene (PE) and polypropylene (PP) as part of the study of plasma-polymer interaction. These polymers, immersed in low-presure oxygen, were exposed to radiation with wavelengths down to 112 nm, the cut off of magnesium fluoride used as a window to separate the polymer specimen from the plasma light source. Total oxygen incorporation in the surface [O], and the formation of hydroxyl, carbonyl, and carboxyl groups were measured using XPS in combination with chemical derivatizations, particularly their dependence upon the radiation spectrum and the oxygen pressure around the sample. In most experiments the surface oxygen concentration [O] attained a constant value that appears to be related to the initial oxidation rate; this suggests a competition between oxygen incorporation and chain scission reactions, followed by the removal of volatile oxidation products. PE is usually oxidized to a higher level than PP, the latter appearing to be more susceptible to reaction with atomic oxygen than PE. A general initiation mechanism for the VUV experiments is proposed that allows us to explain the observed differences in behavior between PE and PP, and the results obtained under different irradiation conditions. The nature of oxidation products is in both cases very similar to what is observed after direct plasma treatment of the polymers. We conclude that short wavelength radiation contributes very appreciably to the observed surface modification effects during plasma treatment of PE and PP. © 1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331208
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  • 3
    Electronic Resource
    Electronic Resource
    The influence of vacuum-ultraviolet radiation on poly(ethylene terephthalate) (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1511-1516 
    Details
    ISSN: 0887-624X
    Keywords: poly(ethylene terephthalate) ; surface treatment ; VUV photochemistry ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(ethylene terephthalate) was exposed to radiation from different kinds of low-pressure plasmas in an oxygen atmosphere. The lower wavelength limit of the spectrum investigated, λ = 112 nm, is the cut-off of magnesium fluoride used for separating the specimen chamber from the plasma light source. The total surface oxygen concentration, and the formation of hydroxyl, carbonyl, and carboxyl groups were evaluated from XPS measurements in combination with chemical derivatizations, and their dependences on the radiation spectrum and the oxygen pressure in the sample chamber have been investigated. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    A Sampler for Total Suspended Particulates with Size Resolution and high sampling efficiency for large particles (1989)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 6 (1989), S. 74-80 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: For a field intercomparison of various widely used dust samplers, a reference instrument was needed. Based on a Wide Range Aerosol Classifier (WRAC), several improvements were introduced compared with the original design including mass flow control of the samplers and the plenum air, brushless threephase blowers, hyperbolic inlets and generally a more compact design, allowing for more comfortable operation. In addition, for measurement of small particle size distributions, a Hauke high-volume, low-pressure impactor (LPI 150/0.15) was included, so that size distribution information with cuts at 0.12, 0.30, 1.19, 3.14, 10.2, 20.4, 37.4 and 60 μm could be obtained. In addition, the aspiration efficiency was measured under in situconditions and parallel measurements were performed with the two reference samplers built so that the performance was well characterized.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19890060112
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  • 5
    Electronic Resource
    Electronic Resource
    Measurement of the Influence of Directed Particle motion on the turbulent particle deposition velocity by means of laser-doppler anemometryDedicated to Professor Kurt Leschonski on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 8 (1991), S. 12-15 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The dry deposition of particles from the atmosphere is not well understood for reasons of surface variabilities and mutual interactions between surface and particles. However, even relatively simple influences of physical parameters have so far resisted successful parameterization, although some progress has been achieved. There is no general way to determine the relative contributions of stochastic turbulent and Brownian diffusion and directed motions (i. e. sedimentation) to the total deposition velocity since they contribute in a nonlinear manner to the total deposition velocity. The directed motion is an unknown function of atmospheric turbulence, the particle diffusion coefficient Dp and the sum of all directed particle motions by thermophoresis, diffusiophoresis, photophoresis, electrophoresis, sedimentation etc. Practically nothing is known about the action of the first three forces and even the easily accessible electrophoresis has not been considered relevant for deposition of atmospheric particles. Because it is relatively easy to change an electric field with all other parameters kept constant and measure the absolute difference in total deposition velocity the following experimental Laser-Doppler study was intended to show the feasibility of the field-changing-technique and the magnitude of the effects without quantitatively determining the electrical mobility distribution as a function of particle size.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19910080104
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  • 6
    Electronic Resource
    Electronic Resource
    Surface modification of polyethylene by remote dc discharge plasma treatment (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 117-124 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The surface modification of polyethylene in a remote nitrogen, oxygen, and hydrogen dc discharge plasma was investigated. In the case of the nitrogen plasma a strong correlation exists between the concentration of active nitrogen species, as detected by Langmuir probe measurements and plasma emission spectroscopy, and the time dependence of the polymer surface modification, as detected by contact-angle measurements. The obtained contact-angle data were interpreted in terms of the acid-base model for the interaction of the test liquid with the polymer surface. There was a great similarity in the functionalization of the polyethylene surfaces treated with nitrogen as well as with oxygen plasma, except in the intial stage, where in the former, mainly functional groups acting as electron acceptors were formed, whereas in the latter a sharp increase in the content of both electron donor as well as electron acceptor groups was detected. Thus, a determining influence of oxygen residues in the remote nitrogen plasma was indicated. The absence of such an effect in the case of the hydrogen plasma could result from direct quenching of reactive oxygen species and / or the chemical reduction of formed oxygen containing functionalities by hydrogen species. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490114
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  • 7
    Electronic Resource
    Electronic Resource
    Surface modification of poly(ethylene) in an rf downstream remote plasma reactor (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1857-1863 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyethylene (PE) was treated in a remote downstream reactor with oxygen, nitrogen, hydrogen, and mixed gas plasma. The effects of these treatments were investigated by contact angle goniometry and x-ray photoelectron spectroscopy (XPS). The oxygen plasma treatment allowed a rapid and efficient hydrophilation of the PE, although the samples were placed far outside the main discharge region. In hydrogen plasma treatment, only a small amount of polar functional groups are formed, while the nitrogen plasma results in a surface similar to that in an oxygen plasma treatment. Thirteen percent of oxygen was found by XPS in these samples, while only 3% of nitrogen was present. The mixed oxygen/hydrogen plasma treatment revealed that 0.1% oxygen in the process gas produced a detectable degree of oxidation. By experiments with quenched atomic oxygen, the singlet molecular oxygen (O½Δ) was found to be the major reactive species in the surface reaction in our system. The role and the source of radiation in this reaction is discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070491016
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  • 8
    Electronic Resource
    Electronic Resource
    Infrared spectroscopic characterization of plasma-treated polyethylene (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 59 (1996), S. 119-124 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thin polyethylene films cast on copper or gold were treated with low-pressure oxygen plasma. Changes in the chemical structure of these films were investigated by infrared spectroscopy using a reflection method in combination with chemical derivatization (CD) reactions. The potential of the CD is demonstrated for hydroxyl groups and carbonyl groups by the reaction with trifluoroacetic anhydride and hydrazine. The reaction conditions were varied to check for side reactions. The results of the derivatization are discussed in terms of secondary structures. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Untersuchung zur phasengrenzseitigen Hemmung der Wasserstoffeffusion bei wasserstoffbeladenen Vergütungsstählen (1993)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 44 (1993), S. 342-344 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Investigation into the effusion behaviour of hydrogen in quenched and tempered steelsThe effusion behaviour of hydrogen in quenched and tempered steel was investigated by means of the ultrasonic damping technique (USDT). The material 34CrMo4 was used in three tempering conditions (I: 850 N/mm2, II: 1000 N/mm2 and III: 1200 N/mm2). The influence of effusion behaviour of different media (imidazole, imidazolidine and EDTA) in dependence of the exposure time was determined. Additionally volumetric permeation experiments and the determination of the hydrogen embrittlement-index (VH) were performed.The results revealed, that the USDT basically is suitable for the quantitative, non destructive measurement of hydrogen in quenched and tempered steel.The investigations showed a significant influence of different parameters on the reproducibility of the results. Especially the influence of media, the microstructure and the coupling of the testing button on the material surface are important for the reliability of the results by using the USDT under practical conditions.
    Notes: Mit Hilfe der Ultraschalldämpfungsmessung (USD) als zerstörungsfreies Prüfverfahren wurde der Einfluß des Auslagerungsmediums auf das Effusionsverhalten des Wasserstoffs in Stahlproben untersucht. Die Auslagerungsmedien waren Imidazol, Imidazolidin, EDTA und Wasser. Die Proben aus dem Vergütungsstahl 34CrMo4 lagen in den drei Vergütungsstufen I (RmI: 850 N/mm2), II (RmII: 1000 N/mm2) und III (RmIII: 1200 N/mm2) vor. Zur Überprüfung der Ergebnisse aus der USD wurden der Wasserstoffversprödungsindex VH ermittelt und volumetrische Permeationsversuche durchgeführt.Die Untersuchungsergebnisse lassen darauf schließen, daß die USD prinzipiell zur quantitativen Erfassung von Wasserstoff geeignet ist.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19930440804
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  • 10
    Electronic Resource
    Electronic Resource
    Über eine radikalische Verdrängungsreaktion vom Typ SH2γ am Triazen-SystemDiese Arbeit wurde vom Fonds der Chemischen Industrie unterstützt. (1971)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 83 (1971), S. 850-851 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19710832109
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