Phenol formaldehyde curing resins

Methylol Terminated, p-Alkyl Substituted, Phenol-Formaldehyde Curing Resin... 

Methylol-terminated para-alkyl-substituted phenol formaldehyde curing resin is a condensation product from a reaction of the proper proportions of para-alkyl phenol with formaldehyde under controlled conditions see Figure 10.67. 

Figure 10.67 Reaction of para-octyl phenol with formaldehyde to produce methylol-terminated para-octyl-substituted phenol formaldehyde curing resin...

Methylol-terminated p-alkyl-substituted phenol formaldehyde curing resin... 

A very small amount of the total formaldehyde is used to make methylol-terminated phenol formaldehyde curing resins, usually used in rubber bladders for tire curing. 

Most processors of fiber-reinforced composites choose a phenol formaldehyde (phenoHc) resin because these resins are inherently fire retardant, are highly heat resistant, and are very low in cost. When exposed to flames they give off very Htde smoke and that smoke is of low immediate toxicity. PhenoHc resins (qv) are often not chosen, however, because the resole types have limited shelf stabiHty, both resole and novolac types release volatiles during their condensation cure, formaldehyde [50-00-0] emissions are possible during both handling and cure, and the polymers formed are brittle compared with other thermosetting resins. 

CF = cardanol-formaldehyde resin (cured) MCPAF = monocar-danyl phosphoric acid-formaldehyde resin (cured) BrCF = bromo derivative of CF BrMCPAF = bromoderivative of MCPAF PF = phenol-formaldehyde (cured) MPPAF = monophenyl phosphoric acid-formaldehyde (cured), BrPF = bromo derivative of PF BrMPPAF = bromoderivative of MPPAF PPF = phenol-formaldehyde resin phosphorylated (cured). 

J. Monni, R Niemela, L. Alvila and T.T. Rakkanen, Online monitoring of synthesis and curing of phenol-formaldehyde resol resins by Raman spectroscopy. Polymer, 49, 3865-3874 (2008). 

Thermosetting adhesives are, in general, two-component systems, and may be cured either at ambient or at elevated temperatures. After the components have been mixed, the glue has a limited time of application. Phenol formaldehyde, polyester resins and epoxies are being used the latter show a very strong adhesion to practically all materials. 

Manley [32] examined a cured phenolic formaldehyde (PF) resin by means of TG-DTA-MS observing a lower sensitivity of TG relative to DTA. However, new TGA instrumental developments have been reported since. The TG curve shows loss of phenol (MS evidence m/z 94) DTA observes water (MS m/z 18), ammonia (MS m/z 17) and formaldehyde... 

Phenol-formaldehyde (PF) resins have been used as model compounds for the study of pyrolysis and combustion reactions that occur in solid fuels [10]. Utilising these resins it is possible to incorporate a wide range of heteroatomic and hydrocarbon moieties to simulate compounds that arise naturally in the solid fuels. A series of phenol resins crosslinked with thiophene, dibenzo-thiophene, diphenylsulfide, benzyl phenyl sulfide, thioanisole, 8-hydroxyquin-oline and 2-hydroxycarbazole were synthesised. These samples were then cured at 200°C (Fig. 15.2.1) and the resulting resins examined by solid-state NMR spectroscopy. The C CP/MAS spectra of a standard PF resin is shown... 

Phenol/formaldehyde novolac resins react with epoxy groups at elevated temperatures to give highly cross-linked systems, with a high service temperature >150°C and excellent chemical resistance. The typical epoxy/ novolac ratio is 0.9 to stoichiometric a tertiary amine accelerator is necessary for complete cure. 

As Figure 5 indicates, the copolymer resins of peanut hulls extract cured much faster than the resorcinol catalyzed commercial phenol-formaldehyde control resin in bonding these thin flakeboards. The cure time needed to retain a thickness of 0.250" (the thickness of stops) can be estimated from the graphs. In so doing, the necessary cure time of the copol3mier resin for the 1/4" oak flakeboards was found to be approximately 104 seconds, whereas, a more than 120 seconds cure time was needed for the commercial control resin. 

Phenolic Based on inorganic resin phenol-formaldehyde pure resins are cured by heat good resistance to chemicals, solvents, water, boiling water, and steam can be reacted with drying oils to give air-dried, oil-based coatings (considered as oil-based coatings). 

Phenolics based on phenol formaldehyde thermosetting resins, two-part cold or heat and pressure cured. More expensive than most adhesives, but gives strong bonds for structural applications and good environmental resistance. 

Using dynamic mechanical analysis the curing reactions of typical phenol-formaldehyde novolac resins were followed. The evolution of various rheological parameters was recorded for samples of the resins on cloth. A third-order phenomenological equation described the curing reaction. The influences of the structure, composition and physical treatment on the curing kinetics were evaluated. 20 refs. 

Both melamine—formaldehyde (MF) and resorcinol—formaldehyde (RF) foUowed the eadier developments of phenol—, and urea—formaldehyde. Melamine has a more complex stmcture than urea and is also more expensive. Melamine-base resins requite heat to cure, produce colorless gluelines, and are much more water-resistant than urea resins but stiU are not quite waterproof. Because of melamine s similarity to urea, it is often used in fairly small amounts with urea to produce melamine—urea—formaldehyde (MUF) resins. Thus, the improved characteristics of melamine can be combined with the economy of urea to provide an improved adhesive at a moderate increase in cost. The improvement is roughly proportional to the amount of melamine used the range of addition may be from 5 to 35%, with 5—10% most common. 

Quinone dioximes, alkylphenol disulfides, and phenol—formaldehyde reaction products are used to cross-link halobutyl mbbers. In some cases, nonhalogenated butyl mbber can be cross-linked by these materials if there is some other source of halogen in the formulation. Alkylphenol disulfides are used in halobutyl innerliners for tires. Methylol phenol—formaldehyde resins are used for heat resistance in tire curing bladders. Bisphenols, accelerated by phosphonium salts, are used to cross-link fluorocarbon mbbers. 

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