New poly(ether urethane)s based on lignin derived aromatic chemicals via A-B monomer approach: Synthesis and characterization

• New A-B monomers were synthesized starting from lignin-derived phenolic acids.
• A-B monomers were self-polycondensed to obtain poly(ether urethane)s.
• Poly(ether urethane) structure and thermal properties were correlated.

ω-Hydroxyalkyleneoxy benzoyl azides were synthesized starting from lignin-derived phenolic acids (vanillic acid and syringic acid) and ω-haloalkanols (6-chlorohexanol and 11-bromoundecanol). These bio-derived A-B monomers were self-polycondensed to afford poly(ether urethane)s which exhibited reasonably high molecular weights (ηinh = 0.41–0.69 dL g−1 and Mn,GPC = 20,000–40,400) and film forming characteristics. Poly(ether urethane) films exhibited % transmittance at 800 nm in the range 80.2–87.6. Poly(ether urethane)s were stable up to 320–340 °C and showed Tg values in the range 40–70 °C. Tg values of poly(ether urethane)s were dependent on length of oxyalkylene spacer and number of methoxy substituents on aromatic ring. Thus, vanillic acid and syringic acid were demonstrated to be valuable starting materials for synthesis of bio-based poly(ether urethane)s.

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