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Paraformaldehyde (PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units. Paraformaldehyde commonly has a slight odor of formaldehyde due to decomposition.
To make polyoxymethylene homopolymer, anhydrous formaldehyde must be generated. The principal method is by reaction of the aqueous formaldehyde with an alcohol to create a hemiformal, dehydration of the hemiformal/water mixture (either by extraction or vacuum distillation) and release of the formaldehyde by heating the hemiformal.
Paraformaldehyde, with the formula HO(CH 2 O) n H. It is a white solid that is insoluble in most solvents. Methanediol, with the formula CH 2 (OH) 2. This compound also exists in equilibrium with various oligomers (short polymers), depending on the concentration and temperature. A saturated water solution, of about 40% formaldehyde by volume or ...
Using acrylamide and paraformaldehyde in 1,2-dichloroethane gives a clear solution upon heating, from which MBA crystallizes. In aqueous media, acrylonitrile also reacts with formaldehyde to give crude N,N′-methylenebisacrylamide, which can be purified by recrystallization with acetone/water. [5]
The phenolic units are mainly linked by methylene and/or ether groups. The molecular weights are in the low thousands, corresponding to about 10–20 phenol units. Obtained polymer is thermoplastic and require a curing agent or hardener to form a thermoset. Hexamethylenetetramine is a hardener added to crosslink novolac. At a temperature ...
Trioxane can be used interchangeably with formaldehyde and with paraformaldehyde, [3] [4] however the cyclic structure is more stable and it can require high temperatures in order to react. It is a precursor for the production of polyoxymethylene plastics , of which about one million tons per year are produced. [ 2 ]
Para tertiary butylphenol formaldehyde resin also known as p-tert-butylphenol-formaldehyde resin (PTBP-FR) or 4-(1,1-dimethylethyl) phenol (PTBP Formaldehyde) is a phenol-formaldehyde resin found in commercial adhesives, and in particular in adhesives used to bond leather and rubber.
Paraformaldehyde, a fixation solution; Perfluoroalkoxy alkane, a plastic or polymer resin; Pulverised fuel ash, a waste product of pulverised coal; Parafluoroamphetamine; Performic acid; See also PFAS, Per- and polyfluoroalkyl substances