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  • 2020-2023
  • 1975-1979  (1,499)
  • 1970-1974  (1,127)
  • Polymer and Materials Science  (2,626)
  • 1
    Electronic Resource
    Electronic Resource
    The effect of solvent traces on the ultraviolet degradation of poly(vinyl chloride) (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 83-97 
    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 ultraviolet degradation of poly(vinyl chloride) films was studied in a photoreactor which supplied energy near 3000 Å. It was noted that the rate of degradation and color development was increased when the level of residual solvent in the cast films was increased. Two solvents were employed in the study: tetrahydrofuran and dichloroethane. The amount of residual solvent was correlated with the height of a characteristic peak at 2800 Å for tetrahydrofuran and 1900 Å for dichloroethane. Films which had very small traces of solvent showed excellent resistance to ultraviolet degradation, even in the absence of ultraviolet stabilizers. The analysis of solubility data showed that chain scission was controlling in the early stages of exposure, while crosslinking was controlling at later stages. As a result, it was not possible to apply Charlesby's treatment of radiation-induced degradation. Comparison with the results obtained by other workers for degradation at 2537 Å showed that degradation at this wavelength was much faster than degradation at 3000 Å. Furthermore, degradation at 2537 Å appeared to be controlled by crosslinking at all stages of exposure.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160108
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrathin coating by plasma polymerization applied to corneal contact lens (1975)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 629-643 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Plasma coating (deposition of polymer under the influence of plasma) is utilized to modify the surface properties of corneal contact lens. An ultrathin layer (thickness of roughly 200 Å) of plasma polymer of acetylene/H2O/N2 is applied to poly(methyl methacrylate) (PMMA) corneal contact lenses. The surface becomes highly wettable with water compared to uncoated lens. When coated and uncoated contact lenses are placed on rabbit eyes, a remarkable difference in accumulation of mucous matter is observed. With the control lenses, the accumulation of mucous matter in a week is sufficient to affect the optical clarity of the lenses, whereas the coated lenses show no change after three months continuous wearing. The comparative degree of adhesion of the corneal epithelium cells onto glass, modified glass, PMMA, and coated PMMA surfaces is studied using tissue cultures and phase contrast microscopy. The coated PMMA surface exhibits a degree of tissue adhesion lower than that of control PMMA and higher than that of glass surface, and no sign of toxicity of the coated surface is observed by the tissue cultures.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820090609
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  • 3
    Electronic Resource
    Electronic Resource
    Fire fatality study (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 3 (1979), S. 211-217 
    Details
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Over a six-year period, 530 fire fatalities resulting from 398 fires were studied in the State of Maryland. The study had two major objectives: (1) to determine the specific cause of death by a detailed autopsy stud of fire victims, and (2) to determine the specific cause of fatality-producing fire by an on-the-scene fire investigation. The fire fatality study was limited to residential fires and to fatalities that occurred within 6 h of the fire. The results of the toxicological analysis show that (1) 60% of the victims had a carboxyhemoglobin value greater than or equal to 50% carbon monoxide saturation, (2) an additional 20% had elevated carboxyhemoglobin with preexisting cardiovascular disease, (3) 11% of the victims had severe burns, (4) 9% were unexplained and (5) 40% of the victims had positive blood alcohol levels with 30% of these meeting the legal definition of intoxication (blood alcohol ≥0.1%). The fire investigations confirmed that the predominant fatal scenario is the cigarette ignition of upholstered furniture or bedding. This scenario accounted for 47% of the fires and 44% of the victims. Alcohol also appears to be significant factor in this scenario.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fam.810030406
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  • 4
    Electronic Resource
    Electronic Resource
    Polyelectrolyte solutions: Intrachain and interchain correlations observed by SANS (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 17 (1979), S. 379-384 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.130170608
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  • 5
    Electronic Resource
    Electronic Resource
    Thermodynamics and kinetics of the interaction of copper (II) ions with native DNA (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 625-661 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Based on equilibrium binding studies, as well as on kinetic investigations, two types of interactions of Cu2+ ions with native DNA at low ionic strength could be characterized, namely, a nondenaturing and a denaturing complex formation. During a fast nondenaturing complex formation at low relative ligand concentrations and at low temperatures, different binding sites at the DNA bases become occupied by the metal ions. This type of interaction includes chelate formation of Cu2+ ions with atoms N(7) of purine bases and the oxygens of the corresponding phosphate groups, chelation between atoms N(7) and O of C(6) of the guanine bases, as well as the formation of specific intestrand crosslink complexes at adjacent G°C pairs of the sequence dGpC. CD spectra of the resulting nondenatured complex (DNA-Cu2+)nat may be interpreted in terms of a conformational change of DNA from the B-form to a C-like form on ligand binding. A slow cooperative denaturing complex formation occurs at increased copper concentrations and/or at increased temperatures. The uv absorption and CD spectra of the resulting complex, (DNA-Cu2+)denat, indicate DNA denaturation during this type of interaction. Such a conclusion is confirmed by microcalorimetric measurements, which show that the reaction consumes nearly the same amount of heat as acid denaturation of DNA.From these and the kinetic results, the following mechanism for the denaturing action of the ligands is suggested: binding of Cu2+ ions to atoms N(3) of the cytosine bases takes place when the cytosines come to the outside of the double helix as a result of statistical fluctuations. After the completion of the binding process, the bases cannot return to their initial positions, and thus local denaturation at the G·C pairs is brought about. The probability of the necessary fluctuations occurring is increased by chelation of Cu2+ ions between atoms N(7) and O of C(6) of the guanine bases during nondenaturing complex formation, which loosens one of the hydrogen bonds within the G·C pairs, as well as by raising the temperature. The implications of the new binding model, which comprises both the sequence-specific interstand crosslinks and the described mechanism of denaturing complex formation, are discussed and some predictions are made. The model is also used to explain the different renaturation properties of the denatured complexes of Cu2+, Cd2+, and Zn2+ ions with DNA.In temperature-jump experiments with the nondenatured complex (DNA-Cu2+)nat, a specific kinetic effect is observed, namely, the appearance of a lag in the response to the perturbation. The resulting sigmoidal shape of the kinetic curves is considered to be a consequence of the necessity of disrupting a certain number of the crosslinks existing in the nondenatured complex before the local unwinding of the binding regions (a main step of denaturing complex formation) may proceed.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180311
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  • 6
    Electronic Resource
    Electronic Resource
    Solvent effects on radical copolymerization of methyl methacrylate and acrylonitrile (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 1531-1534 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die radikalische Copolymerisation von Methylmethacrylat und Acrylnitril wurde in sechs Lösungsmitteln bei zwei verschiedenen Ausgangs-Monomerverhältnissen und 60°C untersucht. Der Stickstoffgehalt der Copolymeren nimmt in der Reihe Chloroform 〈 Dioxan 〈 Benzol 〈 Anisol 〈 Methylpentylketon 〈 Brombenzol zu, was einen Einfluß der Lösungsmittel auf die wachsenden Radikale nahelegt.
    Notes: Radical copolymerization of methyl methacrylate and acrylonitrile has been studied in six solvents at 60°C, and two monomer feed ratios. The nitrogen contents of the copolymers increases in the order: chloroform 〈 dioxane 〈 benzene 〈 anisole 〈 methyl pentyl ketone 〈 bromobenzene, suggesting an influence of the solvent on the growing radicals.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021750514
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  • 7
    Electronic Resource
    Electronic Resource
    Investigations of the structure of polyphenylenes based on ketone acetals by infrared spectroscopy (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 3475-3485 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Struktur der durch Polycyclokondensation von Ketonacetalen aromatischer Acetylverbindungen dargestellten Polyphenylene wurde IR-spektroskopisch untersucht. Es konnte gezeigt werden, daß sich bei der Polycyclokondensation 1,3,5-substituierte Benzolringe bilden, die durch spezifische Absorptionsbanden bei 880 und 1 400 cm-1 charakterisiert werden. Die IR-Daten erlauben, die Anwesenheit von defektiven (d. h. nichtaromatischen) Fragmenten in den Polymerketten abzuschätzen.
    Notes: The structure of polyphenylenes obtained by polycyclocondensation of ketone acetals of aromatic acetyl compounds was investigated by IR spectroscopy. It could be shown that in the course of polycyclocondensation 1,3,5-substituted benzene rings are formed, which are characterized by the specific absorption bands at 880 and 1 400 cm-1. The spectral data permit the evaluation of defective (non-aromatic) fragments in the polymer chains.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021751213
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  • 8
    Electronic Resource
    Electronic Resource
    A cooperative molecular weight distribution test (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 269-282 
    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 development of gel permeation chromatography (GPC) has provided a convenient tool for the rapid determination of molecular weight distribution. The question has arisen as to the suitability of the method for specification purposes. The present work, suggested by the Naval Air Systems Command, represents an attempt to assess the precision of the method through a series of tests carried out by a number of laboratories using identical procedures on the same samples. Ten laboratories agreed to take part. Naval Ordnance Station, Indian Head, worked out standard conditions for operation of the chromatograph, for calibration of the columns, and for analysis of the GPC curves. Two samples of polystyrene were used by the various organizations for calibration of their instruments. Number-average molecular weight, heterogeneity index, and cumulative molecular weight distribution curves were determined on four samples of carboxyl-terminated polybutadiene (CTPB) and two samples of hydroxyl-terminated polybutadiene (HTPB), all unidentified except by letter code. All laboratories used identical directions for setting up CTPB and HTPB calibration curves which were based on curves determined from vapor-pressure osmometer molecular weights and GPC count numbers of fractionated material. Variation among the different laboratories was 0.15 in heterogeneity index, and a maximum of 1200 in molecular weight provided one aberrant set of values was eliminated. The six samples had heterogeneity indices from 1.15 to 1.54, while molecular weight varied from approximately 3000 to 6000. The average coefficient of variation of the molecular weight values was 6.2 ± 0.7%, which is quite acceptable. Variation in heterogeneity index was too great for specification purposes when considered among the different laboratories, but may be sufficiently good when measured by any one laboratory.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170121
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  • 9
    Electronic Resource
    Electronic Resource
    Studies on soluble fraction of glow-discharge polysilazane formed from hexamethylcyclotrisilazane (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 2013-2019 
    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 soluble part of glow discharge polysilazane prepared from hexamethylcyclotrisilazane was studied. The composition of the soluble fraction was examined by gas chromatography and mass spectrometry. It was found that the fraction contained five main components, and two of them, identified by mass spectrometry, were octamethylcyclotetrasilazane and bicyclic silazane dimer. A reaction mechanism leading to dimer formation from hexamethylcyclotrisilazane in glow discharge was proposed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210801
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  • 10
    Electronic Resource
    Electronic Resource
    Corrosion Behaviour of Manganese-Containing Stainless Steels. II. Potentiodynamic measurements in H2SO4 solutions (1973)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 24 (1973), S. 23-28 
    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: Korrosionsverhalten von manganhaltigen nichtrostenden Stählen II. Potentiadynamische Messungen in H2SO4-LösungenStähle mit (%) 17,3 Cr, 5,3 Ni und 0,3 bis 13,9 Mn verhalten sich bei potentiodynamischen Polarisationsversuchen ähnlich wie CrNi-Stähle 18 8. In den Polarisationskurven treten scharfe Spitzen auf, welche der Auflösung des Eisens entsprechen; dann folgt ein Passivitätsbereich mit geringem, potentialunabhängigem Stromfluß; bei einem bestimmten Potential kommt es dann zu einem steilen Stromanstieg. Ebenso findet man in stark verdünnter Säure einen Transpassivitätsbereich, entsprechend der Auflösung von Cr und Mn; der Beginn dieses Bereichs entspricht dem Beginn des steilen Stromanstiegs in konzentrierteren Lösungen. Durch zyklische kathodische Reduktion und anodische Oxidation werden die Spitzen der Kurven im Aktivbereich stark erniedrigt, während der transpassive Bereich dadurch nicht beeinflußt wird. Optimal ist eine Zusammensetzung mit (%) 17,3 Cr, 5,3 Ni und 5,6 Mn; höhere Mn-Gehalte verschlechtern das Korrosionsverhalten.
    Notes: The behaviour of steels with (%) 17.3 Cr, 5.3 Ni, 0.3-13.9 Mn during potentiodynamic polarization k tests is comparable to that of 18 8 CrNi steels. Sharp peaks are found in the polarization curves; they correspond to the dissolution of the iron base: This region is followed by a passive zone characterized by low and potential-independent current flow. At a certain potential, however, a steep current rise sets in. In diluted acid there is even a transpassivity zone corresponding to the dissolution of Cr and Mn. The beginning of this zone corresponds to the beginning of the steep current rise in more concentrated solution. Cyclic cathodic reduction and anodic oxidation results in a considerable reduction of the height of the peaks in the active region, while this treatment has no effect on the transpassive region. The optimum composition of a steel would be (%) 17.3 Cr, 5.3 Ni, 5.6 Mn; higher Mn contents deteriorate the corrosion behaviour.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19730240106
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