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  • 1
    Electronic Resource
    Electronic Resource
    Etching of a low-density polyethylene film by fuming nitric acid (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 249 (1997), S. 33-46 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Filme aus Polyethylen niedriger Dichte (LDPE) wurden mit rauchender Salpetersäure behandelt. Die Oberflächeneigenschaften sowie die Bildung polarer Gruppen wie auf der geätzten Filmoberfläche wurden mit SEM-, IR- und XPS-Methoden analysiert. Die mechanische Festigkeit eines aus dem geätzten LDPE-Film und einem Epoxidharz hergestellten Laminats sowie die Bedruckbarkeit der geätzten Oberflächen wurden untersucht und mit einer unbehandelten Probe verglichen. Die Oberflächenrauhigkeit und die Gegenwart polarer Gruppen erhöhen die mechanische Festigkeit des Laminats aus dem geätzten Film durch mechanische Verankerung und chemischer Wechselwirkungen. Die Oberfläche des behandelten LDPE-Films ist besser bedruckbar als die des unbehandelten Films.
    Notes: Low-density polyethylene (LDPE) films were treated with fuming nitric acid (FNA). The surface characteristics and also the insertion of polar groups like on the etched LDPE film surface were measured by SEM, IR and XPS analyses, respectively. The mechanical performance of a laminate of the etched film with epoxy resin and also the printability of the etched film surface were tested and compared with the unetched sample. The surface roughening and the presence of polar groups enhance the mechanical strength of the laminate of FNA-treated film due to mechanical interlocking and chemical interaction. The printability of the treated film surface is also superior to that of the untreated LDPE film surface.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052490103
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of oligomerization of cardanol using acid catalysts (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 309-315 
    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 kinetics and mechanism of oligomerization of cardanol over acid catalysts were studied. GPC results showed the formation of a mixture of oligomers such as dimer, trimer, tetramer, etc. IR spectra of the products of oligomerization showed a decrease in the intensity of the double bond absorption band at 1630 cm-1 and the disappearance of terminal vinyl bands at 895 cm-1 and 907 cm-1. 1H NMR spectra showed drastic changes in the unsaturated proton resonance signals at 5.5δ with respect to saturated protons at 0.2-2.5δ. The ratio of resonance integrals of unsaturated to saturated protons decreased from 1 : 6.5 to 1 : 20 after oligomerization. GPC studies showed that the rate of formation of the dimer, trimer, tetramer, etc. follow an identical path and that the individual oligomers are formed in the same weight percentage at any time during the reaction. A kinetic scheme is proposed to explain this phenomenon. Kinetic studies showed that the oligomerization reaction follows first order kinetics with respect to the monomer concentration and the rate constant is K = 6.6 × 10-5s-1. A probable mechanism for the oligomerization of cardanol is proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070450213
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  • 3
    Electronic Resource
    Electronic Resource
    Correlation of mechanical property, crosslink density and thermogravimetric behavior of castor oil polyurethane-polystyrene divinyl benzene simultaneous IPN networks (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 34 (1987), S. 1803-1815 
    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: Several simultaneous interpenetrating networks (IPN) of castor oil polyurethane (COPUN) and polystyrene divinyl benzene (PSN) were synthesized under conditions where the free radical polymerization of styrene and the crosslinking reaction of castor oil and toluene diisocyanate progress at comparable rates. Comparison of the mechanical properties and crosslink density of the COPUN and COPUN/PSN-IPNs indicates a marginal increase in tensile strength and crosslink density from COPUN to 60COPUN/40 PSN IPN. IPN samples prepared with further increased PSN content show steady decrease in the above properties. This reversal of the expected trend was attributed to the possible greater molecular interpenetration achieved due to similar gelation times with resultant extension of chains and increase in free volume between crosslinks. This was further confirmed from thermogravimetric data on the initial stages of decomposition of the IPNs.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070340503
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  • 4
    Electronic Resource
    Electronic Resource
    Cis-trans isomerization of polybutadiene double bonds during olefin metathesis (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1183-1193 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cis-trans isomerization of polybutadiene double bonds during metathesis degradation using WCl6/(CH3)4Sn catalyst system has been estimated kinetically along with productive metathesis. The isomerization was followed both for noncrosslinked and for crosslinked polybutadiene. Ninety-six percent cis-1, 4 units are found to isomerize into ca. 75% trans-1, 4 units. The rate of stereomutation is found to be different in the presence and absence of a low-molecular-weight olefin. The results are explained with the help of a stereo model originally proposed by Katz (Advances in Organometallic Chemistry, Academic, New York, 1977, Vol. 16.)
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.170210425
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  • 5
    Electronic Resource
    Electronic Resource
    Insitu dehydro-oligomerization of castor oil, fatty acid ester into esters of dimer and oligomer acids over molybdenum oxide on silica-alumina catalyst (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2317-2327 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A process is described for the conversion of methylricinoleate, the major castor oil, fatty acid ester, directly into esters of dimer and oligomer acids by using molybdenum oxide on a silica-alumina catalyst. The dehydration of the methylricinoleate into a corresponding mixture of conjugated and nonconjugated olefins and the oligomerization reaction took place side by side in a continuous column, fixed-bed reactor. The products are characterized by IR, 1H NMR, and MS. The fragmentation pattern in the mass spectrum of the dimeric species distilled from the mixture reveals that the product contains cyclic and acyclic isomeric structures. The mechanism of dimerization and oligomerization reactions to transition metal complexes and transition metal oxide catalyst systems is reviewed briefly and the possibility of a common mechanism for all similar systems is suggested. A general mechanism for oligomerization reactions to similar catalysts is proposed and the products of the present reaction are explained on the basis of the proposed mechanism.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221003
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetics of oligomerization of methyl ester of dehydrated castor oil fatty acid over molybdenum oxide on silica-alumina catalyst in comparison with the thermal oligomerization process (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 3805-3814 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A process is described for the oligomerization of methyl ester of dehydrated castor oil fatty acid over molybdenum oxide on silica-alumina catalyst. The process is compared with thermal oligomerization. The nature of the reaction in both the processes are shown to be the same from the structural elucidation of the product despite the variation in product composition. The percentage of dimer in the product in both the processes is observed to attain an equilibrium value at around 270°C. The catalytic process is shown to follow a second-order kinetics with respect to the monomer, whereas the thermal reaction follows a first-order kinetics. The kinetic scheme derived for the catalytic process is shown to be consistent with the steps of the general mechanism proposed for oligomerization reactions over transition metal catalysts [V. G. Kumar, S. Venkatachalam, and K.V.C. Rao, J. Poly. Sci. Polym. Chem. Ed., 22, 3850 (1984)].
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170221218
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  • 7
    Electronic Resource
    Electronic Resource
    Oligomerization of styrene over molybdenum oxide on silica-alumina catalyst (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2133-2144 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Styrene was found to yield saturated and unsaturated linear oligomers in the presence of a surface-supported catalyst, molybdenum oxide on silica-alumina. The reaction rates, the structure, and the molecular weight distribution of the products were found to be controlled by the choice of the solvent. Higher-molecular-weight fractions were favored in isooctane, whereas low-molecular-weight oligomers were preferred in dioxane. The reaction followed first-order kinetics with respect to the monomer. End-group analysis suggests a probable cationic mechanism. Approximate transfer constants KtrKp were deduced from product distribution data. The behavior of the surface-supported catalyst was compared with other cationic catalyst systems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.170210722
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