Phenol formaldehyde types

In the paper industry, PEO is widely used as a retention aid and pitch control agent in the newsprint industry (118—135). Typically, a phenol formaldehyde-type resin is added to the substrate before the addition of PEO. The chemical that is added before PEO has been referred to as an enhancer. Recent pubHcations on designing enhancers that work with PEO have resulted in expanding the use of PEO in flocculation of several substrates (128,129). 

Alkylated phenol derivatives are used as raw materials for the production of resins, novolaks (alcohol-soluble resins of the phenol—formaldehyde type), herbicides, insecticides, antioxidants, and other chemicals. The synthesis of 2,6-xylenol [576-26-1] h.a.s become commercially important since PPO resin, poly(2,6-dimethyl phenylene oxide), an engineering thermoplastic, was developed (114,115). The demand for (9-cresol and 2,6-xylenol (2,6-dimethylphenol) increased further in the 1980s along with the growing use of epoxy cresol novolak (ECN) in the electronics industries and poly(phenylene ether) resin in the automobile industries. The ECN is derived from o-cresol, and poly(phenylene ether) resin is derived from 2,6-xylenol. 

Another common gas that appears on the list of potential teratogens is formaldehyde. Since it is normally used as a 40% aqueous solution ("formalin"), it is listed in Table 2 with the organic liquids. Only four of the twenty lab manuals use formaldehyde one in a clock reaction, two to test for the presence of the aldehyde group, and the other to make a polymer of the phenol-formaldehyde type. In none of these is the use of formaldehyde essential. There are other simple clock reactions, there are other less hazardous aldehydes, and there are other polymerization reactions that would be more suitable for an introductory chemistry course. 

The types of adhesives suitable for laminating beams are restricted by the conditions of application and by their end-use requirements. A wider choice of adhesives for plywood depends on whether softwoods or hardwoods are used, whether they are required for internal or external exposures, or whether they are to be used for ornamental or structural purposes. Thus phenol-formaldehyde types would be used for marine or exterior construction uses urea-formaldehyde types would be advantageous for cold pressing, or melamine-urea adhesives might be preferred for hardwood plywood, or lumber-core panels used in furniture production. 

Phenol-formaldehyde type polymers had been the only exterior-durable adhesives for wood bonding, until the recent limited use of isocyanates. Both systems are petrochemical-based. Several researchers substituted carbohydrates for part of phenolic adhesives (1-4) > producing solid, fusible novolak resins. Recently, reaction of carbohydrate acid-degradation products with phenol and formaldehyde has produced liquid resols (5). Gibbons and Wondolowski (6,7) replaced a considerable amount of phenol with carbohydrate and urea to pro-... 

Usually, phenolphthalein-derived polymers are polymerized through the hydroxyl groups, thus destroying their well-known indicator properties. There is one example in which phenolphthalein and o-cresolphthalein 284 have been polymerized with formaldehyde to form phenol/formaldehyde type polymers, for example, 285. These polymers retain the indicating properties of the monomers with potential application in pFl test strips and optical pH sensors <2005PSA1019>. 

Flame retardant under severe 30-34 Phenol-formaldehyde type (Kynol)... 

Saligenin (76) is photochemically reactive (254 nm) when irradiated in basic media (MeOH/HeO). The reaction affords phenol/formaldehyde type resins in reasonable yield. The route to the condensation process involves the formation of the enone (77) by photochemically induced expulsion of hydroxide from the phenolic anion generated from (76). This enone then reacts with another anion ultimately to build up oligomers. Evidence for this process comes from the minor products formed during the reaction. These are the ether (78) which is produced by the addition of methanol (the solvent) to the enone (77). Furthermore the diphenylmethane derivatives (79) and (80) are also formed by the condensation of two substrate molecules either with or without the addition of solvent. Products of this type are considered as good evidence for the condensation reaction proposed. ... 

Gamble JF, McMichael AJ, Williams T, Battigelli M. Respiratory function and symptoms An environmental-epidemiological study of rubber workers exposed to a phenol-formaldehyde type resin. Am Ind Hyg Assoc J 1976 (Sept) 499-513. 

Amberol [Rohm Haas]. TM for maleic-resin and resin-modified and unmodified phenol-formaldehyde-type polymers in solid form. They react with various oils to produce fast-drying, high-gloss protective coatings and vehicles for printing inks. 

Phenol-formaldehyde resin Two-stage phenolic resin Classification Phenol-formaldehyde type resin Properties Sol. in alcohol... 

Reactive resins n. (1) Resins of phenol-formaldehyde type which are beheved to react with drying oils on heating, more particularly those of conjugated types. (2) Resins capable of cross-hnking with themselves or other resins. (3) Resins with a high acid number. 

Given the widespreaid use and interest in ATA for the inhibition of particular cellular processes, and the well documented fact that ccmner-cial lots of ATA are impure, we felt it was necessary to structurally characterize the active con nents present in "ATA preparations. We achieved fractionation by the condtiined use of dialysis and ultrafiltration, and structural elucidation by carbon-13 magnetic resonance spectroscopy. Evidence will be presented that ATA is a mixture of polymers of the phenol-formaldehyde type whose inhibitory potency increases with the average moleculw weight of the polymer fraction. 

Ccmmercially available as well as synthetically prepared samples of ATA consist mostly of a heterogeneous collection of polymers as revealed by fractionation schemes utilizing both dialysis and ultra-filtration, axid by molecular weight measurements. Carbon-13 NNR studies suggest that the polymeric material is of the phenol-formaldehyde type, and inhibitory assays that depend on the formation of a protein-nucleic acid complex reveal that potency varies directly with the molecular weight of the polymer. ATA fractions of molecular weight 400 are essentially inactive. 

Novolaks are phenol-formaldehyde type polymers. Novalaks are synthesised via a polycondensation reaction which is halted before the polymer becomes fully cross-linked. As Novalak polymers contain phenol units, they have reasonable solubility in aqueous base solutions. To act as a positive tone resist, the solubility of the Novolak polymer in basic solutions must be greatly enhanced. This can be achieved by using photochemically reactive additives. The additive used is a diazoanthraquinone, which undergoes a photochemically driven Wolf rearrangement reaction to produce a carboxylic acid (Scheme 13.4). 

Many phenolic compounds other than phenylpropanoids can be obtained from plants catechol, guaiacol, syringic acid, syringaldehyde, gallic acid, vanillin, and vanillic acid are obtained from plants. These phenolic compounds have become candidates for monomers used in the polymer industry. They undergo oxidative polymerization and serve as monomers for phenol-formaldehyde type resins, and some compounds having a hydroxyl group and a carboxylic acid serve as monomers for polycondensation. 

Cardanol is a main component of thermally treated cashew nut shell liquid (CNSL), and is a phenolic compound with a long unsaturated hydrocarbon chain substituted in the meta position (Figure 2.17a). Urushiol, which is obtained from lacquer tree, poison ivy, poison oak, and poison sumac (Toxicodendron), and used for a raw material of a lacquer (urushi) in East Asia, is also a phenolic compound of catechol with a long unsaturated or saturated hydrocarbon chain (Figure 2.17b). Cardanol-based polymers have been reported very often, while there are a few research reports on urushiol-based polymers. Research on polymers synthesized from cardanol or CNSL are reviewed elsewhere.In the late 1980s, cardanol or CNSL-based polymers began to be reported as novel phenol-formaldehyde type resins and novel epoxy resins.Thereafter, Pillai and his co-workers have vigorously studied synthesis of various type of cardanol-based polymers polymers obtained... 

As is the case with phenol-formaldehyde-type resins, the lack of detailed understanding of the reaction mechanisms and complete characterization of the complex polymeric products did not prevent the large scale utilization of furan based network polymers. In both instances, the synthetic chemistry and chemical technology aspects are far better understood than the physical and topological aspects of the solid systems [446, 464-466]. 

Bakelite one of the earliest plastics. Thermosetting resins of the phenol-formaldehyde type with high electrical insulation properties. Used with fillers as moulding materials and in laminates. 

Phenol-formaldehyde type (asymmetric center in the side chain)... 

Finally, the variation of ORD curves of the acid-catalyzed phenol-formaldehyde type... 

In fact, for non-regular GAP, other phenomena can lead to optical activity changes as great as those observed for order-disorder transition of poly-a-aminoacids for instance the first reported example was that of phenol-formaldehyde type polycondensates (VII) derived from A -tosyl-L-tyrosine (VI) and prepared either in acidic or in alkaline media [33]. 

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