ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Polymer and Materials Science  (21)
  • ASTROPHYSICS
  • Lunar and Planetary Science and Exploration
  • 1950-1954  (21)
  • 1952  (21)
Collection
Keywords
Publisher
Years
  • 1950-1954  (21)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Copolymerization theory of the vulcanization of rubber. VI. Hydrogen sulfide effects and some self-limiting features (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 8 (1952), S. 321-335 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Vulcanization with sulfur is ascribed to the formation of sulfur radicals which are believed to copolymerize with the rubber molecule double bonds. Hydrogen sulfide is proposed as necessary for chain initiation but when formed in sufficient amounts serves as a chain terminator. This is believed to lead to numerous self-limiting features including ceiling temperatures, post-vulcanization and delayed action effects. Initiation may result from the oxidation of H2S to sulfur radicals and termination to the formation of HS radicals.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120080306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Molecular weight degradation of polyvinyl acetate on hydrolysis (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 8 (1952), S. 409-423 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When the acetate groups of polyvinyl acetate are removed and subsequently restored, the viscosity of the polymer is usually decreased. It is found that after such processing, vinyl acetate polymers prepared at a given temperature approach a maximum viscosity regardless of the viscosity of the original resins. This maximum is increased by lowering the temperature of polymerization and is different for other vinyl esters. The extent of degradation is negligible at low conversions. It is concluded that this phenomenon is characteristic of the monomer. The chemical bond responsible for the degradation has many of the properties of ester linkages. The resins degrade with both bases and acids although the latter catalyst sometimes requires the presence of water. They also degrade when heated in a solution of pyridine, acetic acid and acetic anhydride. The extent of degradation closely parallels the degree of hydrolysis. It is suggested that these ester linkages are formed during polymerization as a result of transfer with the carbon-hydrogen bonds of the acetate groups of both monomer and polymer. Evidence of another transfer reaction involving the vinyl group, but having no bearing on the degradation, is also advanced. If polyvinyl acetate is alcoholized with an acid catalyst, in the absence of water, the processed resin may have a higher viscosity than would be the case with an alkaline catalyst. How much higher is governed by the type of initiator used in the polymerization. This suggests that polymer molecules may be united under these conditions, but the nature of the reaction is obscure.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120080405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Cross-linking in the polymerization of vinyl benzoate and related compoundsPresented at the International Congress of Pure and Applied Chemistry, New York, September, 1951. (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 8 (1952), S. 91-99 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Branching and cross-linking are noted in emulsion and mass polymerizations involving vinyl benzoate and nuclearly substituted vinyl benzoates. A theory is proposed to account for this phenomenon based on free radical addition to the benzoate nucleus. Six new vinyl esters of substituted benzoic acids are described.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120080107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The hofmann reaction with polymethacrylamide (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 8 (1952), S. 365-370 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reaction of polymethacrylamide, [-CH2C(CH3)(CONH2)-]n, in aqueous solution with hypobromite and hypochlorite has been investigated. Different reaction procedures yielded polymers which were similar, and which contained a small number of primary amino groups, considerable carboxyl and unreacted amide groups and, probably, alkylacylurea groups formed by interaction between adjacent isocyanate and halogenoamide groups. Analytical data supporting these conclusions are presented. The polymer from the Hofmann reaction is soluble in dilute alkali and also in strongly acid media, precipitating on dilution. Methacrylamide monomer reacts with hypochlorite to give N-α-methylvinyl-N′-methacrylurea and acetone.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120080402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Rates of thermal degradation of polystyrene and polyethylene in a vacuumThis work was supported by funds transferred from the Reconstruction Finance Corporation, Office of Rubber Reserve. Paper presented at the Symposium on Polymer Degradation Mechanisms, at the National Bureau of Standards, Washington, D. C., September 24-26, 1951. (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 9 (1952), S. 133-156 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When heated in a vaccum at 325° to 375°C., polystyrene yields mainly the monomer and some dimer, trimer, tetramer, etc., indicating that the breaks in the molecular chains occur largely at the ends. Polyethylene, under similar conditions, but at a some-what higher temperature, yields fragments of an average molecular weight of about 700, indicating that the molecular chains break, mostly at random positions. A study was made of rates of thermal degradation of these two polymers by measuring rates of loss of weight of samples by means of a very sensitive tungsten spring balance enclosed in a vaccum. The samples were limited to 5-6 mg. in order to avoid spattering during degradation. Rate curves plotted against per cent loss of weight by volatilization indicate that in the case of polystyrene the process is intermediate between a zero and first order reaction, while in the case of polyethylene, the process approximates a first order reaction. Activation energies were calculated on the basis of rates of degradation at various temperatures. The values thus obtained for polystyrene and polyethylene are 58 and 68 kilocalories, respectively.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120090203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Amide interchange reactionsPresented at the Fourth Annual Delaware Chemical Symposium, sponsored by the Delaware Section of the American Chemical Society, January 12, 1952. (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 8 (1952), S. 395-407 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: (1) Sebacamide and N,N′-diacetylhexamethylenediamine interchange to produce acetamide and polyhexamethylene sebacamide. (2) The rate is proportional to the concentrations of the two reacting species and to the square root of carboxyl group concentration. (3) The rate increases with increasing concentration of water. Reagents which had been held in the molten state under high vacuum were still capable of reaction. (4) N-Substitution decreases the rate constant; the isobutyl group is more effective than methyl in this respect. (5) As an indication of the amount of interchange occurring during a typical polymerization, it is computed that at least 42% of the amide links interchange during the 66 nylon synthesis. This means that it is not feasible to make nonrandom copolyamides by polymerizing together low molecular weight homopolyamides. Interchange does provide for the production of nonrandom copolymers from two or more high molecular weight homopolyamides.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120080404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Sorption of vapors by polymers (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 9 (1952), S. 93-95 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120090109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Stability of the vulcanized cross link in butyl rubber: Theory and application (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 9 (1952), S. 97-113 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been determined analytically that, when a Butyl vulcanizate softens during exposure to high temperature, the disulfide cross links between polymer chains break down to thiol groups. Of all the accelerator types, tellurium derivatives of dithiocarbamic acids impart the greatest inherent resistance to this reversion. Such a mechanism of breakdown, however, suggested the use of oxidizing agents to reform the disulfide cross linkage, and four metallic peroxides or dioxides have been found effective. These are CaO2, PbO2, MnO2, and SrO2. Barium peroxide is too stable to be an effective oxidizing agent while magnesium peroxide expels oxygen too rapidly for an effective retarder. Other types of organic and inorganic oxidizing agents have not proved beneficial. The fact that an oxidizing action is responsible for retardation of reversion has been demonstrated by the fact that the corresponding mono-oxides of calcium, strontium, lead, and manganese do not perform in the same manner. In rubber technology the stabilization of vulcanized materials by oxidizing agents is novel, and it appears applicable only in the case of Butyl whose low unsaturation offers greater resistance to oxidation of the chain proper. When CaO2 is added to diene type rubbers such as Buna S, Buna N, and natural rubber the common oxidative effects are accelerated. With the Buna rubbers the hardening action is more rapid, while with natural rubber a softening followed by a hardening action is promoted.A practical illustration of this principle of retarding reversion of Butyl vulcanizates by oxidizing agents has been presented. It has been demonstrated in the laboratory that the service life of automotive tire curing bags made from Butyl can be prolonged by the addition of these metallic dioxides or peroxides to the compound.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120090201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Structure of copolymers from polymerization of ethylene of polyvinyl acetate (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 9 (1952), S. 61-68 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The formation of “grafted” vinyl copolymers by polymerizing one monomer in the presence of a preformed vinyl polymer has been extended to a new monomer-polymer combination and one point of attachment of the lateral (grafted) polymer chain has been shown precisely. When ethylene was polymerized in the presence of polyvinyl acetate under a variety of conditions, modified polyvinyl acetates having lateral polyethylene chains were formed. Alkaline methanolysis of such modified polymers yielded mixtures of long-chain fatty acids and ethylene-modified polyvinyl alcohols (which were inseparable from any unmodified polyvinyl alcohol that may have been present). The hydrolysis to long-chain acids shows that polyvinyl acetate acts as a chain transfer agent and that one point of lateral growth of polyethylene chains is the —CH3 in the acetoxy group of polyvinyl acetate. The second hydrolysis product, the ethylene-modified polyvinyl alcohol, shows that chain transfer, and subsequent growth of polyethylene chains, can also occur on the chain carbons of polyvinyl acetate. Oxidation of the ethylene-modified polyvinyl alcohols yielded a mixture of oxalic acid and long-chain fatty acids. At the low ethylene pressures studied (300 to 1200 p.s.i.) only traces to small amounts of low molecular weight polyethylene waxes were formed.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120090105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Zur kenntnis der durchlässigkeit von ultracellafilter-membranen für niedrigmolekulare flüssigkeiten (1952)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 8 (1952), S. 140-146 
    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: A method for the quantitative determination of the permeability of membranes for solvents is reported.The permeability number of Ultracellafilter membranes in benzene can greatly be altered by treating with other liquids for one day. In benzene the permeability number decreases in course of time; after exchanging benzene for methanol it increases very rapidly at first and still continues to increase slightly after one week.
    Notes: Es wird eine Methode zur quantitativen Bestimmung der Durchlässigkeit von Membranen für Lösungsmittel beschrieben.Die Permeabilitätszahl von Ultracellafilter-Membranen in Benzol kann durch eintägige Einwirkung anderer Flüssigkeiten stark geändert werden. In Benzol nimmt die Permeabilitätszahl im Laufe der Zeit ab; sie steigt beim Austausch von Benzol durch Methanol zunächst sehr rasch an und nimmt auch nach einer Woche immer noch schwach zu.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1952.020080204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...