A High-T<sub>g</sub> Polyamide Derived from Lignocellulose and CO<sub>2</sub>
Cristian P. Woroch, Andrew W. Lankenau, Matthew W. Kanan
Abstract
Polymers that are sourced from truly sustainable feedstocks and have favorable physical properties can provide compelling alternatives to conventional petrochemical plastic. In this study, solution-phase anionic ring-opening polymerization is used to synthesize poly(iminomethylene(cis-tetrahydro-2,5-furandiyl)carbonyl) (PITC) from 8-oxa-3-azabicyclo[3.2.1]octan-2-one ((±)-1), a monomer made from lignocellulose and CO2. Under optimized conditions, the reaction proceeds to give near-quantitative yield in minutes at low temperatures. The polymer chain lengths are readily controlled by the amount of N-acetyl lactam activator up to a solubility-limited number average molecular weight (Mn) of ∼30,000. For PITC samples with Mn > 10,000, the glass transition temperature (Tg) reaches an asymptotic limit of 129 °C, which is one of the highest reported values for a nonaromatic polyamide and the highest for a lignocellulose-derived polyamide. Additionally, PITC can be chemically recycled by acid-catalyzed depolymerization and subsequent cyclization to regenerate the lactam monomer.