I. Slonim, S. G. Alekseyeva, Ya. G. Urman
1977
Citations
1
Influential Citations
12
Citations
Journal
Polymer Science U.s.s.r.
Abstract
A method has been developed for 13C NMR analysis of the structure of urea-formldehyde resins containing imidazolidone, triazinone and uronic rings. It is shown that the reaction of urea and formaldehyde with ammonia or hexamethylene tetramine results in the formation of triazinone rings stabilized by methylol groups linked to the “amine” nitrogen of the ring. In a urea-formaldehyde system uronic ring formation takes place in an acid or alkaline medium with a large excess of formaldehyde in the system. Rings of both types add formaldehyde with formation of methylol groups and methylene and methylene ether bridges. The obtained cyclochain structures complement the linear-branched structures formed by urea residues with methylol groups and bridges between the letter.