Synthesis of polyoxazolines using glycerol carbonate derivative and end chains functionalization via carbonate and isocyanate routes

Abstract

We report the cationic ring-opening polymerization of 2-methyl-2-oxazoline (MOx) using bio-based initiator (GCTs). The functional initiator GCTs was prepared by tosylation of the corresponding alcohol: glycerol carbonate (GC). The termination stage of the polymerization was achieved in presence of KOH and the telechelic polyoxazoline carrying five-membered cyclic carbonate and oxazolium end groups (GC-POxium) was converted to ((HO) 2-POx-OH) carrying α-diol and ω-hydroxyl groups. End-functionalized polyoxazolines (HO)2-POx-OH with Mn ranging from 4200 to 8400 g mol-1 were synthesized. According to GPC results, the polymerizations of MOx using GCTs and other initiator coming from 1,2-isopropylidene-glycerol (Solk-Ts) were compared. On the basis of FTIR and NMR spectroscopies, the chemical modification of end chains of polyoxazolines was investigated by two alternative synthetic routes. The isocyanate route is a postpolymerization urethanization. The nucleophilic reactivity of the α-diol and ω-hydroxyl groups of (HO)2-POx-OH was studied with functional isocyanate (TESPI). In the carbonate route, the electrophilic reactivity of α- and ω-end groups of GC-POxium were explored with amine. It was demonstrated that during the termination stage of the polymerization in presence of aliylamine both urethane linker in α-end chain was synthesized and the ω-oxazolium group was converted into terminal amine. The carbonate route is an alternative to synthesize urethane without isocyanate. © 2010 Wiley Periodicals, Inc.