• Top library match: Poly(ethylenimine),epichlorohydrin modified #7725

• The library confidence is low, with all listed top candidates reported at zero similarity, S-O the leading entity cannot be treated as a reliable identification.
• No related-literature interpretation was recovered to narrow the assignment.
• The carbonyl band at 1728 cm-1 is not naturally explained by every leading library candidate and suggests either chemical modification, additive content, oxidation, or a different class of material than the top hit alone.
• The present evidence cannot distinguish confidently among amine-containing polymers, hydroxylated polymers, ether-rich polymers, or mixed/modified resin systems.
• The 3329 cm-1 band could arise from O-H, N-H, or both, and FTIR alone here does not separate those contributions securely.
• The 1643 and 1728 cm-1 bands leave open whether the sample contains amide, ester, aldehyde/ketone, oxidized polymer functionality, or a blend component.
• Because the best library hit is not supported by a meaningful similarity score, the final conclusion must remain at a broadened material-direction level.

Recommended next steps: Re-measure the FTIR spectrum with improved baseline quality and broader sample preparation control, especially to confirm the shape and intensity of the 3329, 1728, and 1643 cm-1 bands. Check whether the 1643 cm-1 feature decreases after thorough drying; if it does, adsorbed water is contributing and the remaining functional-group assignment will be clearer. Collect complementary Raman or solid-state NMR data to distinguish polyamine, polyalcohol, and polyether character. If the sample is soluble, use NMR or LC/MS after suitable preparation to determine whether the 1728 cm-1 band comes from ester/carbonyl modification or from a separate additive.