Sustainable Polyamides Enabled by Controlled Ring-Opening Polymerization of 4-Hydroxyproline-derived Lactams

Aliphatic polyamides have been considered as eco-friendly materials, useful for a wide range of applications. However, it still presents obstacle to produce sustainable aliphatic polyamides from abundant renewable sources. Herein, we describe that 4-hydroxyproline (4-HYP), a renewable resource, was readily converted to its corresponding bicyclic bridged lactam monomers bearing pendant Boc-protected secondary amino group, and oligo-ethylene glycol group. Lithium hexamethyldisilazide (LiHMDS)-mediated polymerization of the resulting monomers exhibited a controlled feature, affording sustainable aliphatic polyamides with number-average molecular weight up to 73 kg/mol and a low molecular weight distribution Ð<1.28. Overall, this work can lead to a novel kind of functional and sustainable polyamides with potential applications, including degradable plastics, and drug delivery.