Preparation of Clickable Poly(3-hydroxyalkanoate) (PHA): Application to Poly(ethylene glycol) (PEG) Graft Copolymers Synthesis.

A new synthesis of amphiphilic biodegradable copolymers consisting of hydrophobic poly(3-hydroxyalkanoate) (PHA) backbone and hydrophilic poly(ethylene glycol) (PEG) units as side chains is described. Poly[(3-hydroxyoctanoate)-co-(3-hydroxyundecenoate)] (PHOU) was first methanolyzed and its unsaturated side chains were quantitatively oxidized to carboxylic acid. Esterification with propargyl alcohol led to an alkyne-containing "clickable" PHA in 71% conversion. Its reactivity was successfully demonstrated by grafting azide-terminated PEG chains of 550 and 5 000 g · mol(-1) , respectively. All products were fully characterized using GPC, (1) H, and COSY NMR.