Novel Aliphatic Polyester-Based Macromonomers
Oligomer of poly(3-hydroxy propionate) (P3HP) was synthesized via base-catalyzed hydrogen transfer polymerization (HTP) of acrylic acid using sodium tert-butoxide as a strong basic catalyst. Structural analyzes based on 1H-NMR and MALDI-MS revealed that the oligomeric products obtained possess olefinic chain-ends that are open to further end-group functionalization. End-group modifications were performed through monobromination by HBr in acetic acid, debromination by bromine and epoxylation by hydrogen peroxide. Extents of conversions of olefinic end-groups to the corresponding functional groups were followed by using 1H-NMR and MALDI mass spectrometry. According to the analyzes, the three modification approaches resulted with end-group modified oligomers with high yield. Monobrominated oligomer was then converted to azide-ended oligomer through treatment with sodium azide. The exchange of bromide atom at the end group to azide group was also studied using by MALDI mass spectrometry. The all end-group modified products may be regarded as novel macromonomers for applications such as synthesis of amphiphilic block copolymers, surface modification and grafting agents.