Poly(amide urethane)s with functional/reactive side groups based on a bis-cyclic bio-based monomer/coupling agent

Glycerol and d,l-homocysteine thiolactone – two bio-based building blocks – were used to prepare a bis-cyclic AA′ monomer (or coupler) with an ethylene carbonate and a thiolactone ring linked by an O-methyl urethane spacer. On reaction of this monomer with diamines at 70 °C poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups are produced in one step. Monodisperse diamines of low molecular weight (MW), monodisperse amino telechelic poly(ethylene oxide) (MW = 897.10) and polydisperse amino telechelic polytetrahydrofuran (Mn = 1100) were used as amine building blocks. By reaction of the coupler with diamines at room temperature only the thiolactone ring is converted. Consequently, a bis(ethylene carbonate) bis(thiol) is obtained if one equivalent diamine is reacted with two equivalents of coupler. Reaction of this intermediate with a second diamine leads to poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups and alternating amine building blocks. Post-polymerization modification of thiol side groups leads to polymers with designed properties. The microstructure of the obtained polymers was proven by 1H NMR and Raman spectroscopy; the molecular weights were determined by size exclusion chromatography.