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Phenol-formaldehyde resins, as a group, are formed by a step-growth polymerization reaction that can be either acid- or base-catalysed.Since formaldehyde exists predominantly in solution as a dynamic equilibrium of methylene glycol oligomers, the concentration of the reactive form of formaldehyde depends on temperature and pH.
Another method entails methylation of phenol with methanol over a solid acid catalyst, often comprising magnesium oxide or alumina. Temperatures above 300 °C are typical. Anisole converts to cresols under these conditions. [5] [6] Another isomer of cresol is called Benzyl alcohol, or alpha-cresol (α-cresol).
Phenolic, amino, and furan resins all cured by polycondensation involving the release of water and heat, with cure initiation and polymerisation exotherm control influenced by curing temperature, catalyst selection or loading and processing method or pressure – the degree of pre-polymerisation and level of residual hydroxymethyl content in ...
Para tertiary butylphenol formaldehyde resin, also known as p-tert-butylphenol-formaldehyde resin (PTBP-FR), is a thermoplastic phenol-formaldehyde resin found in commercial adhesives, particularly glues used to bond leather and rubber. It has broad usage in a large variety of industries and can be found in many household textile products and ...
Phenol-formaldehyde resins (PF) were the first commercially relevant impregnation resins, made by reacting phenol and formaldehyde, creating a polymer network inside of the wood upon curing. [7] Phenol can react with formaldehyde at the ortho and para positions, generating mono, di, and trimethylolphenol as the reaction products. [6]
A common method for hydroxymethylation involves the reaction of formaldehyde with active C-H and N-H bonds: R 3 C-H + CH 2 O → R 3 C-CH 2 OH R 2 N-H + CH 2 O → R 2 N-CH 2 OH. A typical active C-H bond is provided by a terminal acetylene [1] or the alpha protons of an aldehyde. [2]
These are made by the reaction of phenols, formaldehyde and primary amines which at elevated temperatures (400 °F (200 °C)) undergo ring–opening polymerisation forming polybenzoxazine thermoset networks; when hybridised with epoxy and phenolic resins the resulting ternary systems have glass transition temperatures in excess of 490 °F (250 °C).