Isocyanate-Free Synthesis and Characterization of Renewable Poly(hydroxy)urethanes from Syringaresinol

In the context of replacement of petro-sourced and toxic bisphenol A (BPA), syringaresinol, a naturally occurring bisphenol deriving from sinapic acid, has been proposed as a greener and safer alternative. This work focuses on its applications for nonisocyanate polyurethane (NIPU) synthesis. A five membered cyclic carbonate SYR-CC has been prepared by carbon dioxide addition to bis-epoxy monomer SYR-EPO derived from syringaresinol. Upon polyaddition of SYR-CC with different biosourced and petrosourced diamines, the resulting polyhydroxyurethanes were fully characterized by structural (Fourier transform infrared, 'H nuclear magnetic resonance, high performance liquid chromatography size exclusion chromatography) and thermal analyses (thermogravimetric analysis, differential scanning calorimetry). These thermoplastics displayed high molar mass (M-n = 5.4 kg mo1(-1)), excellent thermal stabilities (T-d5% = 267 - 281 degrees C) and glass transition temperatures (T-g) ranging from 63 to 98 degrees C. The coupling of SYR-CC with a triamine gave thermoset material with interesting T-g (62 degrees C) and high thermal stability (T-d5% = 225 degrees C).