Degradable and Thermally Stable Spiro Polycycloacetals from Renewable Resources

A series of partially bio-based spiro polycycloacetals were synthesized using bio-renewable feedstocks, such as vanillin and its derivative syringaldehyde, along with pentaerythritol and commercially available co-monomers including 4,4′-difluorobenzophenone and bis(4-fluorophenyl) sulfone. These spiro polycycloacetals displayed high thermal stabilities (degradation temperatures in the range of 343 – 370 °C, as quantified by 5% mass loss) and glass transition temperatures (in the range of 179 – 243 °C). Importantly, these polymers were effectively degraded to small molecules under acid-catalyzed hydrolytic conditions in less than 7 h. The kinetics of hydrolytic degradation was quantified through <i>in situ</i> NMR analyses.