Results 81 to 90 of about 154 (134)

Degradation kinetics of functionalized novolac resins

Polymer Degradation and Stability, 2010
Abstract We report the relationships between the degradation behaviors (i.e. the degradation kinetics, degradation activation energy, weight loss conversion, and char formation) and the structure features in three modified novolac resins bearing different curable functional groups and aromatic units i.e. Carbonyl phenyl azo novolac resin (CPAN), 4-(4-
Hsin Ho Wu, Peter P. Chu
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Strategic synthesis of model novolac resins

Tetrahedron Letters, 1994
Abstract Model novolac resins which contain the maximum number of free ortho positions for reaction with the curing agent hexamethylenetetramine (HMTA) have been prepared. The key transformation was the ion assisted ortho -specific phenol-formaldehyde oligomerization of suitably protected precursors.
Pauline J. de Bruyn, Audrey S.C. Lim, Mark G. Looney, David H. Solomon   +3 more
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Effect of an epoxidized novolac resin anhydride structure on the properties of resin

Polymer Engineering & Science, 1973
AbstractThe properties of an epoxidized novolac resin cured with two homologous series of substituted succinic anhydrides (alkenyl and alkyl) have been determined and the effects of anhydride structure on properties have been evaluated. Substituted succinic anhydrides yield cured resins with lower strengths, lower heat distortion temperatures, and ...
Ronald E. Johnson, A. L. Fricke
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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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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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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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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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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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