• Top library match: (4-methyl-2-oxochromen-7-yl) hexadecanoate #11807

• The carboxyl assignment at 1510 cm⁻¹ [6] is not a typical marker for polyurethane hard segments; it may reflect carboxylate end‑groups or an additive.
• The low library match (15 %) and the absence of a specific polyurethane reference in the top‑hit list introduce uncertainty about the precise chemical identity.
• The library search did not retrieve a high‑confidence polyurethane match; the proposed chemical class relies heavily on the direct literature evidence.
• The 1510 cm⁻¹ band assignment remains ambiguous—it could be aromatic skeletal vibration rather than carboxyl.
• Without additional reference spectra or complementary techniques, the exact composition (polyester‑urethane, polyether‑urethane, etc.) cannot be determined.

Recommended next steps: Acquire reference spectra of aromatic polyurethane elastomers or coatings for direct library comparison. Perform complementary analyses such as thermogravimetry (TGA) to detect urethane decomposition steps or NMR to identify specific monomers. If possible, synthesize a model polyurethane from a common aromatic diisocyanate and polyol to match the infrared fingerprint. Re‑run the FTIR search with a library focused on industrial polymers, particularly polyurethanes and polyesters.