Phenol-formaldehyde resins novolacs

Synonyms Alkyl-phenol formaldehyde resin Novolac resin Novolak resin One-stage resin PF... 

A hard carbon with high capacity can be made from epoxy novolac resin [12]. The epoxy resins used cost about US 2.50 per pound and give pyrolysis yields between 20 and 30%. However, it is well known that phenolic (or phenol-formaldehyde) resins can be pyrolyzed to give hard carbons with a yield of over 50% [42]. In addition, these resins cost about USSl.OO per pound. Phenolic resins therefore offer significant cost advantages over epoxy resins, so we... 

The thermal production of volatile compounds progresses in the temperature range 450-620°C in phenol-formaldehyde resin. From novolacs about 20%, while from cured... 

Figure 14.7 Representative structures of phenol-formaldehyde resins (a) novolac (formed under acidic conditions), and (b) resole (formed under basic conditions).

Therefore, the actual functionality of phenol in a Novolac must be less than 2. The figure often quoted of 2.31 has no chemical or physical meaning in terms of the structure of a phenol-formaldehyde resin. An actual functionality above 2 can only eventuate when the P/F ratio is greater than 1, that is, when gelation can occur. 

The commercial importance of phenol-formaldehyde resins has resulted in extensive studies of these systems, with the aim of identifying the reaction mechanisms and intermediates that occur during subsequent polymerization reactions. However, the complexity of Novolac-type systems has made a detailed understanding of the subsequent chemical processes and their relationship to the physical properties of the final polymerized product difficult. Thus, it is necessary to simplify the system in order to more readily unravel this complexity. Model compounds are frequently used to understand complicated chemical systems and their application to phenol-formaldehyde systems has been well documented . ... 

These resins (Resole or Novolac) are used as curing agents or hardeners for epoxy molding compounds for electronics applications such as computer components. 0-cresol-formaldehyde resins have heen also used to modify phenol-formaldehyde resins, and in laminates. 

Attempts have been made over time to improve the physical properties of novolacs. The use of phenol formaldehyde resins prepared in alkaline medium in photoresist compositions is mentioned in a Kalle Co. AG patent. The use of polyvinyl ethers in combination with novolacs to impart stickiness and plasticization action to the latter was patented by Christensen. Steinhoff, Isaacson, and Roelants of the Shipley Company mention the use of vinyl ethers in a patent on roller coating. Lower alkyl polyvinyl ethers, such as methyl, ethyl, butyl, and isobutyl, are added to novolac resins to improve coating flexibility and adhesion to metal surfaces as well as to improve resistance to mildly alkaline solutions. The use of styrene, methyl styrene, and styrene-maleic anhydride copolymers in combination with novolac was mentioned in several patents of both Shipley and Kalle Co. AG. When novolac is copolymerized with maleic anhydride, a resin that is readily soluble in alkaline solutions is obtained. ... 

Novolac type phenol formaldehyde resins are generally used as binders in these applications. This mechanism is shown in the scheme ... 

Phenol formaldehyde resins (pol3miethylene phenylene) are polymers with irregular cross-linked structure. During friction of resol- and novolac-t3rpe phenol formaldehyde pol3miers two processes take place simultaneously, namely structuring (aftercure) via recombination of weak ester groups... 

Leo Hendrik Baekeland s process for the phenol-formaldehyde polycondensation resin that he called Bakelite was patented in 1907 and commercialized by his General Bakelite Company, established in Perth Amboy, New Jersey, in 1910. A British factory, a subsidiary of Bakelite s German holding company, was opened at Cowley, Middlesex, in 1914. Baekeland also coined the name Novolac, which at one time was used as the trade mark for Novolak phenol-formaldehyde resins, following his observation that they behaved like lac resins. Phenol-formaldehyde resins were found to be thermosetting (hard and unmouldable when heated), and formed by condensation ... 

Phenol-formaldehyde resin. See Novolac resin Phenolic resin... 

Hydrolyzed casein Hydrolyzed milk protein binder, nylon Epoxy-novolac binder, oil cosmetics Hydrolyzed rice protein binder, oil hair care Hydrolyzed rice protein binder, oil oil-absorbent formulations Hydrolyzed rice protein binder, oil skin care Hydrolyzed rice protein binder, oil-well sands Phenol-formaldehyde resin Phenolic resin binder, organic solvent systems Ethyl hydroxyethyl cellulose binder, outdoor paints Potassium silicate binder, paints... 

SiC nanofibers by melt-spinning of polymer blends have been prepared from PCS as a SiC ceramic precursor and a novolac-type phenol-formaldehyde resin [121]. These nanofibers were amorphous, about 100 nm in diameter, more than 100 (un long, and were rich in oxygen. 

Novolac Phenol-formaldehyde resins, PE Perstorp Bakelite S.A. 

Epoxy group functionalized polyphenylsilsesquioxane oligomers were used for modification of phenol-formaldehyde oligomer (novolac resin -SF-0112) for increasing their flexibility, their hydrophobic surface properties, thermal stability and flame-retardant properties. Novolac resin - SF-0112 contains a little amount of free phenols (0.9%) compared with other phenol-formaldehyde oligomers. 

Pol)merization reaction of phenol-formaldehyde oligomer (novolac resin - SF-0112) with tetraepoxypolyphenylsilsesquioxanes was carried out in melt condition at 125 5°C temperature at various ratios of initial compounds, without catalyst. The samples were tested on contain of epoxy groups during the reaction. It was shown that during synthesis of block-copolymers the reaction rate decreases, which may be explained by presence of free phenols in used phenol-formaldehyde oligomer. In accor-... 

Formaldehyde reacts with phenols giving methylol (hydroxymethyl)-substituted phenols, which are the monomers in the resin. Formaldehyde also creates chemical bonds between monomers. This bond can be either of the methylene type (-CH2-) or of the methylene-ether type (-CH -O-CH -), thus forming dimers, trimers, tetramers and so on. Phenol-formaldehyde resin can be produced in two principal ways, either as resol or novolac resins. 

Phenol-formaldehyde resin included in standard or supplementary test series should be of the resol type, as this type of resin contains higher levels of potent allergens than novolac resins. 

Phenol-formaldehyde resins resemble a group of chemicals that contain the formaldehyde structure but are not necessarily associated with formaldehyde allergy. Resols and novolacs are distinguished within that group. While the chemical curing of novolacs requires the presence of formaldehyde to react with the phenol terminate group, resols do not. Resols are intermediates, which, in turn, need heat to cure (Malten 1984). Para-substituted phenol resins do not crosslink but adhere readily under pressure. Among... 

Phenol-formaldehyde resin, 1% pet, Novolac (abrasives) (see Chaps. 74, 81)... 

Synonyms P-F-R-2 resol phenol formaldehyde resin phenol formaldehyde phenol polymer with formaldehyde formaldehyde-pnenol polymer paraformaldehyde-formaldehyde-phenol polymer paraformaldehyde-phenol polymer phenol-formaldehyde polymer Novolac Resole resol based on phenol, resorcinol, and formaldehyde... 

Epoxy NovolaC Resins. Epoxy novolacs are multifunctional epoxies based on phenolic formaldehyde novolacs. Both epoxy phenol novolac resins (EPN) and epoxy cresol novolac resins (ECN) have attained commercial importance (53). The former is made by epoxidation of the phenol-formaldehyde condensates (novolacs) obtained from acid-catalyzed condensation of phenol and formaldehyde (see Phenolic Resins). This produces random ortho- and para-methylene bridges. 

Other well known condensation polymers include phenol-formaldehyde resins, the prototype of which is Bakelite (Figure 13.15 C). Such structures were known as early as the 1870s, and in the early 20th century these tough, durable thermosets were among the first synthetic polymers of commerical importance. More modern versions of this type of polymer are known as Novolac. This chemistry is also that which make.s calixarenes (Chapter 4), which are cyclic tetramers rather than linear polymers. 

The early history of polymers is really the conversion of natural polymers into useful materials. Examples include the vulcanization of rubber (Goodyear, 1839), celluloid (which is plasticized cellulose nitrate—Hyatt, 1868), and cellulose-derived fibres, e.g. cuprammonia rayon (Despeisses, 1890) and viscose rayon (Cross, Bevan and Beadle, 1892). The first truly synthetic polymer, that is, one made from laboratory chemicals, was Bakelite (Bakeland, 1907). This was made from phenol and formaldehyde. Bakeland probably did not know the chemical structure of the Bakelite, but he did realize that organic chemicals containing multiple functionality yielded insoluble materials. The various phenol-formaldehyde resins (PF), e.g. Bakelite and novolacs, were thus obtained in an empirical manner. 

Novoloid "A manufactured fiber containing at least 85 percent by weight of a cross-linked novolac. Novolac is an epoxide phenolic formaldehyde resin." ... 

Phenol-formaldehyde resins have been widely used for brown and black electrical fittings, and they represent a thermosetting condensation polymer. Depending upon the ratio of phenol to formaldehyde and the pH of the reaction mixture a resole or a novolac is formed by the substitution of formaldehyde molecules at different positions around the benzene ring. In the case of resoles, phenol groups are... 

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