Identify ureaformaldehyde resin from following polymers?

Step-by-step solution

Urea-formaldehyde resin is a condensation polymer formed by the reaction between urea ( NH₂-CO-NH₂ ) and formaldehyde ( HCHO ). The initial reaction involves the formation of methylol urea derivatives, which then undergo condensation with the elimination of water molecules to form a cross-linked polymer network. The repeating unit of the urea-formaldehyde polymer chain is derived from linking the nitrogen atoms of urea with the methylene ( -CH₂- ) group from formaldehyde. The repeating unit is [-NH-CO-NH-CH₂-]_n .