Results 171 to 180 of about 947 (216)

Cardanol‐based novolac resins as curing agents of epoxy resins

Journal of Applied Polymer Science, 2009
AbstractTwo different novolac resins, named Nov‐I and Nov‐II, containing an amount of unreacted cardanol of 35 wt % and 20 wt %, respectively, were synthesized by the condensation reaction of cardanol and paraformaldehyde using oxalic acid as catalyst. Cardanol is the main constituent of cashew nut shell liquid, a renewable natural resource.
Pietro Campaner, Daniele D'Amico, Luigia Longo, Cristina Stifani, Antonella Tarzia   +4 more
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Thermal degradation of epoxy novolac‐phenol formaldehyde novolac resin systems

Journal of Applied Polymer Science, 1991
AbstractThe evolution of organic vapors from encapsulants at elevated temperatures has been implicated as the source of the degradation of the gold–aluminum intermetallic of the wire that connects the bond pad to the leadframe in an integrated circuit.
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Thermally stimulated depolarization current of novolac resin

Journal of Thermal Analysis, 1997
A novolac phenol-formaldehyde resin was investigated via the thermally stimulated depolarization current, using integral and partial measurements in the temperature range from 137 to 270 K. Tow broadened peaks, assigned as Β1, and Β2, appeared at about 160 and 190 K. The influence of water and ¯Mn was investigated. The activation energy Eavs.
M. Topić, Z. Katović
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Synthesis of novolac resins: 2. Influence of the reaction medium on the properties of the novolac oligomers

Polymer, 1991
Abstract The polycondensation of m -cresol with formaldehyde catalysed by oxalic acid in the presence of water-miscible organic solvent was investigated. The influence of the reagents' molar ratio and the effect of the nature and quantity of the solvent used on the molecular weight characteristics of the oligomers formed and on the content of free ...
St. Miloshev, P. Novakov, Vl. Dimitrov, I. Gitsov   +3 more
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Novel process of isolating novolac resin fractions

SPIE Proceedings, 1997
Typical phenol/formaldehyde resin syntheses generate a broad distribution of molecular weight fragments with a wide polydispersity. A process was developed to isolate novolak resin fractions of narrow polydispersity from phenol- formaldehyde condensation products in ethyl lactate without any high temperature distillation.
M. D. Rahman, Ping-Hung Lu, Michelle M. Cook   +2 more
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Dielectric investigations on novolac phenol‐formaldehyde resin

Acta Polymerica, 1995
AbstractPermittivity ϵ′ and dielectric loss ϵ″ of novolac have been determined in the temperature interval from —150 to 150°C and in the frequency interval from 102.5 to 106 Hz. Novolac exhibits a main and a secondary relaxation process. For the main relaxation a master curve of ϵ″ was calculated, the shape of which was described by the Havriliak ...
C. Holland, W. Stark, G. Hinrichsen
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Thermal Stability of a Para-Cresol Novolac Resin

Journal of Thermal Analysis and Calorimetry, 1998
The thermal stability of p-cresol novolac resin was studied by means of DSC, X-ray diffraction, thermogravimetry and SEC investigations. After 30 thermal cycles in which the same sample was heated, cooled and heated again, without attainment of the temperature of degradation at any time in the experiment, important structural modifications are observed.
A. Hamou, C Devallencourt, F. Burel, J. M. Saiter, M. Belbachir   +4 more
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Addition-curable phthalonitrile-functionalized novolac resin

High Performance Polymers, 2012
A novel addition-curable novolac resin with phthalonitrile groups (PN) was successfully synthesized by a simple nucleophilic substitution reaction between the novolac resin and 4-nitrophthalonitrile. The final product was characterized with gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectrometry, and ...
Boxing Zhang, Zhenhua Luo, Heng Zhou, Feng Liu, Ruilian Yu, Yuexiu Pan, Yun Wang, Tong Zhao   +7 more
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An investigation of novolac resins by gel permeation chromatography

British Polymer Journal, 1971
AbstractIn the preparation of novolac resins, three possible dimers with slightly different molecular dimensions may be produced in the polymerisation reaction. Gel permeation studies were carried out on four novolac resins prepared using different acid catalysts, and the results indicated that the nature of the catalyst influences the type and ...
P. G. Montague, F. W. Peaker, P. Bosworth, P. Lemon   +3 more
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Catalytic graphitization of novolac resin for refractory applications

Ceramics International, 2018
Abstract This study investigated how to induce graphite generation from the carbonization process of novolac resins using conditions that can be adopted for carbon-containing refractories (CCRs) production. The effect of boron oxide or boric acid (graphitizing agents), cross-linking additive (hexamethylenetetramine) and some processing parameters ...
S.I. Talabi, A.P. Luz, A.A. Lucas, C. Pagliosa, V.C. Pandolfelli   +4 more
openaire   +1 more source