Rapid Sulfur-Oxazoline Polymerization for Biobased Dynamic Polyamide Networks

Abstract

Inverse vulcanization has been continuously studied for over 10 years and extended to a wide range of organic crosslinkers. However, most reported systems demand high temperature and hours to complete. Here, the reaction between 2-methyl-2-oxazoline or 2-ethyl-2-oxazoline and sulfur is found to complete within 6 mins at 140 oC in the absence of any catalyst, and generate sulfur-chain modified polyamides. The sulfur-oxazoline reaction proceeds well in a broad range of charging ratios (sulfur>10wt%). With a bulkier substitution, 2-phenyl-2-oxazoline was almost inert to sulfur at 160 oC, and would take 2 hours at 180 oC to reach complete conversion. Sulfur-modified polyamide networks from the crosslinking of sulfur with biobased oxazoline-ene difunctional monomers exhibited tunable mechanical properties and photothermal properties for photo triggered shape programming.