Library

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
  • 2020-2024
  • 1980-1984  (6)
  • 1910-1914
  • 1984  (6)
  • Physics  (4)
  • Chemical Engineering  (2)
  • 1
    Electronic Resource
    Electronic Resource
    A quantitative description for the optical properties of crystalline polymers applied to polyethylene (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 328-344 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 quantitative model which described the microscopic and macroscopic refractive index properties of uniaxially oriented crystalline polymers has been extended in relation to molecular bond polarizabilities in this work. Application of this extended modeling methodology in analyzing measured refractive index data for a series of unoriented and oriented samples of linear polyethylene provided Δco = 0.0585 and Δao = 0.194 as the most probable crystalline and noncrystalline intrinsic birefringences for samples exhibiting spherulitic morphology. With these intrinsic birefringences, noncrystalline orientation functions were determined from the optical measurements coupled to the model and the results compared to values obtained from infrared measurements. This comparison of noncrystalline orientation functions, as well as from low density polyethylene reported by other investigators, provided experimental justification for our modeling methodology to examine the possibility of changing intrinsic birefringences for polyethylene as a function of orientation and morphology. The results of this examination demonstrated that values for Δco = 0.0585 and Δao = 0.12 should be used for both low and high density polyethylene samples oriented above the spherulitic to fibrillar transition region.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240507
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Radiolysis of resist polymers. IV. Poly(p-substituted-α-methylstyrene)s (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 213-223 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of parasubstituents on the radiation chemistry of poly(α-methylstyrene) (PMS) was compared for the fluoro (PFMS), chloro (PCMS), bromo (PBMS), isopropyl (PiPMS), and methoxy (PMeOM) derivatives. Radiolysis yields, ESR spectra, and GC—MS analysis of products were obtained. PMS and PFMS have similar low radiolysis yields, products, and product distributions. Only main-chain radicals which persist to 200° were observed. PCMS has increased values of Gs, Gx, and Gr. The product analysis results suggest that the presence of chlorine contributes to the primary process by dissociative electron capture and enhances the cleavage of α-methyl group. Irradiation of PBMS caused crosslinking and yielded few volatile products. PMeOMS and PiPMS gel readily by γ-irradiation and may be useful as negative radiation resists.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220120
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Radiolysis of resist polymers. III. Copolymers of methyl-α-chloroacrylate and trihaloethylmethacrylates (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 195-211 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homopolymers of 2,2,2-trifluoroethyl(methacrylate) (TFEMA) and 2,2,2-trichloroethyl-(methacrylate) (TCEMA) and copolymers with methyl-α-chloroacrylate (MCA) in a range of compositions were synthesized. The reactivity ratios were obtained; the two copolymerizations were close to ideal. Poly(MCA) showed Gs = 7.4 and Gs = 0.9 by γ-radiolysis. On the other hand, poly(TFEMA) and poly(TCEMA) and Gs values of 2.0 and 2.4, respectively, and Gx = 0. Radiolysis of copolymers was initiated to a large degree by dissociative electron capture by the halogen atoms in both comonomers, as revealed by the ESR spectra of radicals derived from them. Germinal recombinations in irradiated poly(TFEMA) suggested the presence of radicals in proximity. This process was absent in the copolymers. GC-MS analysis of volatile products and other supporting evidence showed that TFEMA monomers tended to depolymerize; the TCEMA monomers did not. The radiolysis yields varied monotonically with the comonomer composition for the MCA-TFEMA system but the yield-composition relationship was irregular in MCA-TCEMA copolymers. Four noncrosslinking systems are potential radiation resists arranged in increasing order of promise: poly(TFEMA) (Gs = 2.0, Tg = 70°); poly(TCEMA) (Gs = 2.7, Tg = 142°); poly(94MCA-co-6TCEMA) (Gs = 2.7, Tg = 142°); and poly(68MCA-co-32TFEMA) (Gs = 3.0, Tg = 112°). These materials merit further investigation for E-beam or x-ray lithographic applications. Mechanisms of radiolysis for these materials, based on ESR, GC-MS, and radiolysis yield data, were discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Dynamic mechanical experiments for probing process-structure-property relations in amine-cured epoxies (1984)
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 5 (1984), S. 124-140 
    Details
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Dynamic mechanical experiments were performed on an amine-cured high performance epoxy system containing two types of epoxies and one amine. The system approximates a commercial resin system used widely as matrix material for graphite composites and whose main ingredients and composition are 88.5 percent of tetraglycidyl 4,4′-diamino diphenyl methane (TGDDM) and 11.5 percent of polyglycidyl ether of Bisphenol A Novalac epoxy with varying compositions of 4,4′-diaminodiphenyl sulfone (DDS), ranging from 19 to 40 PHR. Specifically, the effects of DDS and Novalac content as well as processing conditions including the particle size of solid components, the mixing speed, mixing temperature, and the mixing duration of the components on the dynamic mechanical properties of the epoxy polymer were investigated. A viscoelastic transition in the dynamic spectrum which was observed to be quite sensitive to the sample's Tg in conjunction with incomplete crosslinking reactions allowed for interrelating the composition and processing variables to the structure and bulk properties of this epoxy system.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pc.750050203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Semiconducting poly(monocyanoacetylenes) (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2749-2766 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(monocyanoacetylenes) (PMCA) were synthesized by anionic, Ziegler-Natta, metathesis, and photo initiations. The Ziegler-Natta-catalyzed polymers probably have highly stereoregular cis-transoid structure that contains very few defects and the nitrile groups are difficultly cyclized. It has M̄n = 1100. PMCA obtained by anionic polymerization at -78°C has M̄n ∼ 4800; it is rich in trans-transoid structures but probably contains other isomeric units as well. The unpaired spin concentrations in these polymers are very high, comparable to that in trans-polyacetylene (PA) isomerized above 150°C. UV irradiation initiated rapid polymerization of cyanoacetylene in solid state at low temperature but the products were bleached in color after long irradiation. The unpaired spins in PMCA are immobile; nitrile cyclization causes some decrease in EPR linewidth and increase in room-temperature conductivity (σRT). There was also a large increase in unpaired spin concentrations to about 200 monomer units/spin. Iodine doping increases σRT to about 10-3 (ω cm)-1 but the dopant is readily removed by evacuation and the polymer returns to its original insulating state. The properties of pristine and doped PMCA, such as EPR g-value, ΔHpp, T1, T2, and σRT are very similar. The similarities persist after cyclization and doping for this pair of polymers. These properties are also compared with those of poly(methylacetylene), poly(phenylacetylene), poly(dicyanoacetylene) and PA, and the significance is discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Thermal analysis of the pyrolytic behaviors of a highly crosslinked polymer (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 3851-3864 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermogravimetric-mass spectrometric (TG/MS) and differential scanning calorimetric (DSC) techniques were used in the characterization of oxidative and nonoxidative degradation reactions of a highly crosslinked divinylbenzene/styrene copolymer. When the copolymer was subjected to a temperature-programmed air environment, four exothermic reactions were detected. The initial small exothermic reaction, starting at ca. 125°C and reaching its maximum at ca. 180°C, was presumed to result from the decomposition of peroxides. The second exothermic reaction, which overlapped with the initial one and peaked at ca. 270°C, was attributed to oxidation with a significant amount of oxygen uptake and liberation of some gaseous products such as CO2, styrene, benzaldehyde, ethylstyrene, and ethylbenzaldehyde. The strongest exothermic reaction took place at ca. 290-380°C and had its peak at ca. 360°C. Associated with this reaction was the generation of many gaseous pyrolysates, as given above. The exothermic reaction continued at a relatively constant rate from ca. 380°C to the maximum temperature of the experiment (500°C) with the release of only one gaseous product (CO2). The initial exothermic reaction can be eliminated by controlled thermal decomposition of peroxides; therefore, a more thermally stable polymer can be obtained. Exothermic reactions, starting at ca. 170°C, were observed. Pyrolytic reactions in an inert gas were also studied.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221222
    Library Location Call Number Volume/Issue/Year 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...