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  • 2020-2023
  • 1970-1974  (215)
  • 1971  (215)
  • Polymer and Materials Science  (215)
  • 1
    Electronic Resource
    Electronic Resource
    Radiation-induced crosslinking of cellulose with acroleinPaper presented at IUPAC meeting in Macromolecular Chemistry, Budapest, August 26, 1969. (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 1013-1025 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The process of radiation-induced crosslinking of cellulose is found to be highly influenced by radiation dosage and dose as well as by the solvents used and their concentration. The best crease resistance has been obtained in cases when cellulose is crosslinked with acrolein in the vapor phase. Moreover, the process is entirely radiation-induced and practically no homopolymer is formed. Chemical analysis and investigations of infrared spectra indicate that crosslinking proceeds on vinyl as well as on aldehyde groups of acrolein.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.150090416
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  • 2
    Electronic Resource
    Electronic Resource
    Stereochemistry of nucleic acids and their constituents. X.For part IX of this series, see Sundaralingam and Arora.1 solid-slate base-slacking patterns in nucleic acid constituents and polynucleotides (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 175-219 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The base-stacking patterns in over 70 published crystal structures of nucleic acid constituents and polynucleotides were examined. Several recurring stacking patterns were found. Base stacking in the solid state apparently is very specific, with particular modes of interaction persisting in various crystalline environments. The vertical stacking of purities and pyrimidines in polynucleotides is similar to that observed in crystals of nucleic acid constituents. Only partial base overlap was found in the majority of the structures examined. Usually, the base overlap is accomplished by positioning polar substituents over the ring system of an adjacent base. The stacking interactions are similar to those found in the crystal structures of other polar aromatic compounds, but are considerably different from the ring-ring interactions in nonpolar aromatic compounds. Apparently, dipole-induced dipole forces are largely responsible for solid-state base stacking. It is found that halogen substituents affect base-stacking patterns. In general, the presence of a halogen substituent results in a stacking pattern which permits intimate contact between the halogen atom and adjacent purine or pyrimidine rings. Considering differences in the stacking patterns found for halogenated and nonhalogenated pyrimidines, a model is proposed to account for the mutagenic effects of halogenated pyrimidines.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360100113
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  • 3
    Electronic Resource
    Electronic Resource
    The influence of chemical structure on the dynamic properties of sulfur-vulcanized, carbon black-reinforced natural rubber (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 1855-1868 
    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: A comparison is made of the composition and properties of the different rubber vulcanizate networks obtained by varying the ratio of sulfur to sulfenamide accelerator and by the thermal aging of vulcanizates containing predominantly polysulfide crosslinks. It is concluded that the changes in network structure which can take place, for example, during the service life of natural rubber tires are not the direct cause of failures of the type associated with rubber fatigue at high temperatures. However, a reduction in the total number of crosslinks can accelerate failure by increasing the amount of heat generated during flexing. More stable networks giving improved resistance to fatigue at high operating temperatures are obtained by the use of higher ratios of accelerator to sulfur than are conventionally employed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150805
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  • 4
    Electronic Resource
    Electronic Resource
    Glass transition phenomenon in vinylidene chloride-acrylonitrile copolymers (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 2687-2697 
    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: Investigations of glass transition phenomena were carried out on vinylidene chloride - acrylonitrile copolymers, purified commercial samples of known composition. With a view to analyzing this effect, the following physical parameters were investigated: specific volume Vs,25, Tg, and volume expansion coefficients αL, αg, and Δα. The experimental results were analyzed on the basis of semiempirical and theoretical equations describing transitions to the glassy state. It was found that Tg dependence on weight fraction C2 of acrylonitrile may be described by Wood's equation, with k = 5.88. Applying Gibb's and Kanig's theories as well as relations given by Hirai and Small, the energies associated with intermolecular interactions (A*AB, E0, Eh, CED), and intramolecular interactions (stiffness energy ε) were calculated for copolymers of different composition. The copolymer Tg was found, above all, to depend on the stiffness energy ε, which increases with increasing acrylonitrile content in the copolymer.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070151109
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  • 5
    Electronic Resource
    Electronic Resource
    Circular dichroism calculation for random-coil polypeptide chains (1971)
    New York : Wiley-Blackwell
    Biopolymers 10 (1971), S. 2051-2061 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method of calculation of the circular dichroism (CD) of random-coil polypeptides has been developed by means of a Monte-Carlo approach to the treatment of statistical systems and exciton theory of optical activity of polymers. The contribution of π-π* and n-π* amide transitions to the CD has been taken into account. The π-π* transition gives rise to two CD bands: a negative short-wavelength band and a weak positive long-wavelength one. The n-π* transition gives rise to one negative CD band.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360101102
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  • 6
    Electronic Resource
    Electronic Resource
    Viscous behavior of some liquid rubber resins (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 1963-1980 
    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 flow behavior of several low molecular weight polymers has been studied as a function of shear rate and temperature. These polymers, which had terminating hydroxyl or bromine groups, included homopolymers of polybutadiene and acrylonitrile-butadiene and styrene-butadiene copolymers. Viscosity was measured as a function of shear rate for the temperature range 25°-35°C, and the limiting zero shear viscosities were obtained for the range 25°-60°C. A cone plate viscometer was employed to measure the effect of shear rate on viscosity, and a Brookfield viscometer was used to verify the zero-shear rate values. A tendency of the fluid to flow out of the cone-plate gap was observed for some of the materials studied. From the viscosity data, characteristic times were estimated, and the data were compared with two constitutive equations. A modified Arrhenius equation was fitted to the zero-shear viscosity data. In the case of one material, it was possible to test the Nakajima relationship between viscosity and molecular weight distribution. The dependence of material parameters on temperature is discussed in detail.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150814
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  • 7
    Electronic Resource
    Electronic Resource
    Hydrolyzed starch-polyacrylonitrile graft copolymers: Effect of structure on propertiesPresented at the Fifth Great Lakes Regional Meeting of the American Chemical Society, Peoria, Illinois, June 10-11, 1971. (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 3015-3024 
    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: 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.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070151211
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  • 8
    Electronic Resource
    Electronic Resource
    A device to study the degradation of blood in a shear field with controlled wall effects (1971)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 5 (1971), S. 315-324 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A technique is described for studying shear-induced degradation of blood with near-uniform shear exposure to walls of a single material. The device used is a specially designed coni-cylindrical viscometer with essentially all blood-contacting surfaces constructed of a single test material. The technique developed permits exposure of blood only to this material under such conditions that significant shear occurs only in the viscometric region of the device. Contact with air is prevented. Preliminary data are reported for blood taken from fasting dogs and tested in a prototype device constructed of polycarbonate (Lexan). Venous blood was found to hemolyze much more than arterial blood and the extent of hemotysis increased with time. Changes were also observed in the electrophoretic pattern of the plasma proteins.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820050404
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  • 9
    Electronic Resource
    Electronic Resource
    Perm-selective dialysis membranes. I. Films based on dimethylaminoethyl methacrylate copolymers (1971)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 5 (1971), S. 415-445 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: New synthetic polymer membranes prepared from copolymers of dimethylaminoethyl methacrylate are reported. Membrane transport characteristics are compared with those of standard cellulose films currently used in hemodialysis. The membranes are obtained as films by casting solutions of vinyl copolymers prepared by emulsion polymerization techniques. The new membranes show selectivity towards certain blood components under the test conditions used. The clinical procedure for ethylene oxide sterilization has been adapted to give chemical modification of dimethylaminoethyl methacrylate tertiary amine groups. With acrylonitrile as comonomer, polymer membranes which are both watersensitive and insoluble are obtained. The permeability of such films is controlled by varying processing time. Infrared spectra of processed and unprocessed films are discussed and reasons put forward for the change in membrane properties brought about by processing. Membrane behavior when acrylonitrile is replaced by methacrylonitrile or methyl methacrylate indicates the probable necessity of having a strongly electron-attracting comonomer for successful modification.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820050502
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  • 10
    Electronic Resource
    Electronic Resource
    Tolerance of modified poly(glycol methacrylates) by the organism (1971)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 5 (1971), S. 225-238 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Investigation has been made of the short-term tolerance of hydrophilic polymers on the basis of poly(hydroxy ethyl methacrylates) containing various amounts of acidic and basic groups. The worst tolerance was found with gels containing basic groups alone.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820050309
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