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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.
Making Bakelite is a multi-stage process. It begins with the heating of phenol and formaldehyde in the presence of a catalyst such as hydrochloric acid, zinc chloride, or the base ammonia. This creates a liquid condensation product, referred to as Bakelite A, which is soluble in alcohol, acetone, or additional phenol. Heated further, the ...
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]
Formaldehyde is a common precursor to more complex compounds and materials. In approximate order of decreasing consumption, products generated from formaldehyde include urea formaldehyde resin, melamine resin, phenol formaldehyde resin, polyoxymethylene plastics, 1,4-butanediol, and methylene diphenyl diisocyanate. [40]
The synthesis of first truly synthetic polymeric material, bakelite, was announced by Leo Baekeland in 1907, through a typical step-growth polymerization fashion of phenol and formaldehyde. The pioneer of synthetic polymer science, Wallace Carothers , developed a new means of making polyesters through step-growth polymerization in 1930s as a ...
The main ingredients of any Phenol formaldehyde resin is a phenol or substituted phenol and formaldehyde. The two main components of Para tertiary butylphenol formaldehyde resin are thus Para tertiary butyl phenol and formaldehyde. [3] There have been a number of patents on their production. [4] [5]
A phenol formaldehyde resin, it can be worked with files, grinders, and cutters, and polished to a fine sheen. Catalin is produced by a two-stage process, different from other types of phenolic resins, and does not contain fillers, such as sawdust or carbon black. Catalin is transparent, near colorless, rather than opaque.
The curing process is by condensation and a typical figure for Redux Liquid 775/Powder 775 is 30 minutes at 293 °F (145 °C) under a pressure of 100 psi (690 kPa). This is not critical and variations in curing-time and/or temperature may be used to increase shear and creep strength at temperatures above 140 °F (60 °C).