Results 131 to 140 of about 585 (182)
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The curing of novolacs with paraformaldehyde
Journal of Applied Polymer Science, 1982AbstractThe curing of novolacs with paraformaldehyde is analyzed with several experimental techniques (DSC, IR, sol fraction) as well as statistical arguments. Results for typical novolacs show that a maximum crosslinking density is attained at a mass ratio mP/mN close to 0.20.
H. E. Adabbo, R. J. J. Williams
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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 +3 more
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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 +3 more
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Thermal degradation of epoxy novolac‐phenol formaldehyde novolac resin systems
Journal of Applied Polymer Science, 1991AbstractThe 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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Polymerization of unsaturated novolac ester
Polymer Science U.S.S.R., 1964THE valuable properties of phenol-formaldehyde resins have been known for a long time and account for their wide application in the various branches of industry. However, certain shortcomings of these resins necessitate their chemical modification and numerous papers deal with this problem (see e.g. [1]).
Yu.S. Lipatov +2 more
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Curing of novolac–lignocellulosic composites
Polymer International, 1995AbstractNovalac resin (N) with hexamethylenetetramine (HTA) was cured with biomass (B) or Kraft lignin (KL) or hydroxymethylated Kraft lignin (KLH) or cellulose (CEL). The agricultural/industrial by‐product of olive stones was used as biomass. Kraft lignin, hydroxymethylated Kraft lignin and cellulose were isolated from the biomass.
J. Simitzis +2 more
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Statistical aspects for the production of novolacs
Polymer, 1982Abstract Statistical parameters for the phenol (P)-formaldehyde (F) condensation under acid conditions are derived in the frame of Flory-Stockmayer's theory. Phenol is assigned an average functionality f = 2.31 as proposed by Drumm and Le Blanc (1972).
J. Borrajo +2 more
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The structure and viscoelasticity of novolac resins
Polymer Journal, 2014In this work, we discuss the dynamic viscoelasticity of three novolac resins with different molar masses and methylene linkage patterns (para–para′, ortho–ortho′ and ortho–para′ methylene linkages) to clarify the relationship between the structure and viscoelastic properties of novolac resins.
Satoshi Maji +2 more
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Dielectric studies on sulphonated novolacs
European Polymer Journal, 1980Abstract The dielectric constants of novalac type of phenolic resins and their sulphonated derivatives were studied as a function of frequency, temperature and extent of sulphonation. The effect of moisture on the dielectric constant has also been reported.
P.S. Vishwanathan +2 more
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Preparation of formylated Novolacs and their photoreaction
Polymer, 1994Formylated Novolacs were prepared by the reaction of Novolacs with formic acid-acetic anhydride in the presence of pyridine in tetrahydrofuran at room temperature. When the resulting formylated Novolacs films were exposed to deep-ultra-violet light, photochemical decomposition of the formyl group was observed.
Nobuyoshi Ito +2 more
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SPIE Proceedings, 1996
Supercritical fluids were used to fractionate a conventional 60 meta/40 para cresol novolac into five narrow polydispersivity fractions. Single and multiple fractions were esterified with a DNQ moiety and recombined to obtain a resist having essentially the same molecular weight and composition as the original parent novolac.
Alfred T. Jeffries III +5 more
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Supercritical fluids were used to fractionate a conventional 60 meta/40 para cresol novolac into five narrow polydispersivity fractions. Single and multiple fractions were esterified with a DNQ moiety and recombined to obtain a resist having essentially the same molecular weight and composition as the original parent novolac.
Alfred T. Jeffries III +5 more
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