Synthesis of poly (L-lactide)-grafted pullulan through coupling reaction between amino end-capped poly(L-lactide) and carboxymethyl pullulan and its aggregation behavior in water

Poly(L-lactide) (PLLA) with terminal primary amino groups (PLLA-NH2) was synthesized and used to construct PLLA-grafted pullulan (Pul-g-PLLA). It consisted of a hydrophilic carboxymethyl Pul (CM-Pul) main chain and hydrophobic PLLA graft chains that were created through a direct coupling reaction between PLLA-NH2 and CM-Pul using 2-ethoxy-1-(ethoxycarbonyl)-1,2-dihydroquinoline as a condensation reagent. Pul-g-PLLAs with over 78 wt % sugar unit content were found to form nanometer-sized aggregates in water. (C) 2004 Wiley Periodicals, Inc.