Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Acid-catalyzed phenolics

Curing time is reduced by increasing the curing temperature. Resistance to weather, boiling water, and biodeterioration is satisfactory. Resistance to elevated temperatures is also satisfactory but inferior to that of heat-cured phenolic and resorcinol adhesives. Excess acidity due to poor control of the acid catalyst content often leads to wood being damage on [Pg.163]

Alkyl-substituted phenols have different reactivities than phenol toward reaction with formaldehyde. Relative reactivities determined by monitoring the disappearance of formaldehyde in phenol-paraformaldehyde reactions (Table 7.3) show that, under basic conditions, meta-cresol reacts with formaldehyde approximately three times faster titan phenol while ortho- and para-cresols react at approximately one-third the rate of phenol.18 Similar trends were observed for the reactivities of acid-catalyzed phenolic monomers with formaldehyde. [Pg.384]

Acid-Catalyzed Phenol-Formaldehyde Condensation (Novolaks)... [Pg.297]

An emulsion polymer-isocyanate adhesive, a crosslinked polyvinyl acetate adhesive, a resorcinol-formaldehyde adhesive, a phenol-resorcinol-formalde-hyde adhesive, and an acid-catalyzed phenolic-formaldehyde adhesive developed bonds of high shear strength and wood failure at all levels of acetylation in the dry condition. A neoprene contact bond adhesive and a moisture-curing polyurethane hot-melt adhesive performed as well on acetylated wood as untreated wood in tests of dry strength. Only a cold-setting resorcinol-formal-... [Pg.304]

In a positive-tone resist, the areas that are exposed to the radiation develop away into the solvent faster than unexposed areas, resulting in a positive-tone image of the mask. The majority of commercial, positive-tone, nonchemically amplified resists used today are variations of the well-known, two-component, diazonaphthoquinone-novolac resist [5]. Novolac is a name generally given to acid-catalyzed phenol formaldehyde condensation polymers of the type shown in Fig. 2. [Pg.3321]

Table 5.6 Cure Conditions of Acid-Catalyzed Phenolics ... Table 5.6 Cure Conditions of Acid-Catalyzed Phenolics ...
Finally, the variation of ORD curves of the acid-catalyzed phenol-formaldehyde type... [Pg.42]

See other pages where Acid-catalyzed phenolics is mentioned: [Pg.9]    [Pg.117]    [Pg.298]    [Pg.200]    [Pg.9]    [Pg.79]    [Pg.304]    [Pg.305]    [Pg.333]    [Pg.104]    [Pg.104]    [Pg.105]    [Pg.5506]    [Pg.80]    [Pg.2074]    [Pg.163]    [Pg.163]    [Pg.163]    [Pg.131]    [Pg.131]    [Pg.132]    [Pg.46]   
See also in sourсe #XX -- [ Pg.104 ]

See also in sourсe #XX -- [ Pg.131 , Pg.132 ]



SEARCH



Acidic phenols

Phenol acid-catalyzed

Phenol acidity

Phenol acids

Phenolic acidity

Phenolic acids

Phenolics phenolic acids

© 2024 chempedia.info