Phenol - aldehyde polymers

Phenol - aldehyde polymers. L. Baekland (1909) first demonstrated the possibilities of the reaction between phenol and formaldehyde from the commercial view point. Condensation in the presence of either... 

Oglialoro modification of, 708 Perkin triangle, 108, 218f Kon modification of, 109 Peroxides, detection of, in ether, 163 removal from diethyl ether, 163 removal from isopropyl alcohol, 886 Petroleum ether, purification of, 174 Phenacetin, 996, 997 1 10-Phenanthroline, 991, 992 p-Phenetidine, 997, 998 Phenetole, 665,670 Phenobarbitone, 1003,1004,1005 Phenol, 595, 613 Phenol aldehyde polymers, 1016 formation of, 1022 Phenolphthalein, 984, 985 action as indicator, 984 ... 

Phenol-aldehyde polymers n. Common name for phenol, polymer with formaldehyde. It is also commonly known as phenol-aldehyde resin. 

Post alkylation of phenol-aldehyde polymers [154]. Melamine-containing phenolic resin compositions [155]. 

Among the polymeric stabilizers may be listed poly-condensed polymers based on alkyl phenols, aldehydes, and ketones of the aliphatic series, where = 1 - 8 and R,R means alkyl [24], Na, K, Ca phenolates of poly-condensed polymers [25], and also products of epichlor-ide with one or more aliphatic amines C3—C30 [26]. 

In far too many instances trade-name polymer nomenclature conveys very little meaning regarding the structure of a polymer. Many condensation polymers, in fact, seem not to have names. Thus the polymer obtained by the step polymerization of formaldehyde and phenol is variously referred to a phenol-formaldehyde polymer, phenol-formaldehyde resin, phenolic, phenolic resin, and phenoplast. Polymers of formaldehyde or other aldehydes with urea or melamine are generally referred to as amino resins or aminoplasts without any more specific names. It is often extremely difficult to determine which aldehyde and which amino monomers have been used to synthesize a particular polymer being referred to as an amino resin. More specific nomenclature, if it can be called that, is afforded by indicating the two reactants as in names such as urea-formaldehyde resin or melamine-formaldehyde resin. 

Terpenes are polymers of the 5-carbon compound isoprene (Figure 1.12) and, as such, generally display properties similar to those of hydrocarbons. Terpenoids are substituted terpenes (i.e. contain additional chemical groups, such as an alcohol, phenols, aldehydes, ketones, etc.). Only a few such substances could be regarded as true drugs. Terpenes, such as limonene, menthol and camphor, form components of various essential oils with pseudo-pharmaceutical uses. A number of these molecules, however, exhibit anti-tumour activity, of which taxol is by far the most important. 

In addition to these reactions, aldehyde-phenol, aldehyde-urea, aldehyde-melamine and many other aldehyde-based polymers are prepared by polycondensation processes. The first step in a typical reaction of this type is... 

Baekeland, L. H. (1863-1944). Bom in Ghent, Belgium. He did early research in photographic chemistry and invented Velox paper (1893). After working for several years in electrolytic research, he undertook fundamental study of the reaction products of phenol and formaldehyde, which culminated in his discovery in 1907 of phenol-form-aldehyde polymers originally called Bakelite. The reaction itself had been investigated by Bayer in 1872, but Bakeland was the first to learn how to control it to yield dependable results on a commercial scale. The Bakelite Co. was founded in 1910 and now is Bakelite AG. 

Novolac (novolak) According to ASTM D 883, a novolac is a phenolic-aldehyde resin, which, unless a source of methylene groups is added, remains permanently thermoplastic. For a preferred definition, see phenolic novolac. However, the term is also used in connection with epoxies. Lenz RW (1967) Organic chemistry of synthetic high polymers. Interscience Publishers Inc., New York. 

The most commonly known phenolic composite group is phenol formaldehyde polymers (phenoplasts). They are produced by polycondensation of a phenol and a mixture of phenols (phenol and phenol derivatives like cresol-resorcinol or para tertiary butyl phenol) with an aldehyde, usually formaldehyde and hexamethylene tetramine. Reaction of formaldehyde with phenol (up to 3 moles of formaldehyde can react with one mole of phenol - phenol acts as a three functional monomer) yields methylol groups in the ortho and para positions of the phenol molecule. In a further reaction, the methylol groups condenses with another molecule of phenol to form a methylene bridge. In practice, a prepolymer (usually a powder) is prepared first which is then cured later to the shape of the article in the mould. 

Casting of acrylic polymers differs from that of phenol-formaldehyde polymers in that considerably more polymerization must take place. Further, the time, temperature, and catalyst must be carefully controlled. Benzoyl peroxide is usually employed as a catalyst. However, other materials can be used, such as diacyl peroxides, aldehyde peroxides, ketone peroxides, alkyl hydroperoxides, alkyl peresters, and alkyl acid peresters. 

The calixarenes (from the Greek calix, meaning chalice) are a family of structures that have seen extensive use in many contexts. Shown below is the remarkable, one-step synthesis of the prototype calixarene. This condensation reaction is a variant of the phenol-aldehyde condensation that produces bakelite, the first synthetic polymer. Early workers spent considerable effort to optimize this synthesis, biasing the product toward the calixarene... 

Phenol-fomaldehyde polymers are polymers formed by the interaction of a phenol, or a mixture of phenols, and formaldehyde. Commercial materials are most commonly based on phenol itself other phenols such as cresols, xylenols and resorcinol are used to a limited extent. It may be noted that several aldehydes other than formaldehyde have been used to prepare phenolic polymers but none has attained appreciable commercial significance. 

This volume continues in the tradition of Volume I in presenting detailed laboratory instructions for the preparation of various types of polymers such as urea, melamine, benzoguanamine/aldehyde resins (amino resins-amino-plasts), phenol/aldehyde condensates, epoxy resins, silicone resins, alkyd resins, polyacetyls/polyvinyl acetals, polyvinyl ethers, polyvinyl pyrroli-dones, polyacrylic acids, and polyvinyl chloride. Polyvinyl acetate and related vinyl esters, allyl polymers, acetylene polymers, maleate and fumarate polymers, and several other addition-condensation polymer types will be covered at a later date in Volume III. 

Other thermosets besides phenol-aldehyde which are formed into network polymers by similar reactions are urea-aldehyde and melamine-aldehyde polymers. 

Uses Raw material for surfactants, demulsifiers, lubricants coupling agent for pigments and dyes cosolvent for Insecticides, germicides resin modifier for phenolic-aldehyde, polyester, PC polymers In photographic Industry Properties SI. pink to wh. waxy solid sol. In org. soivs. Incl. aliphatic hydrocarbons m.w. 304 sp.gr. > 1.0 m.p. 49-51 C (760 mm) b.p. 190-195 C (1 mm) ref Index 1.4750... 

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