Syntheses, Characterization, and in Vitro Degradation of Ethyl Cellulose-graft-poly(E-caprolactone)-block-poly(L-lactide) Copolymers by Sequential Ring-Opening Polymerization
writer：Weizhong Yuan, Jinying Yuan, Fengbo Zhang, and Xuming Xie
keywords：Ethyl Cellulose-graft-poly(E-caprolactone)-block-poly(L-lactide)
source：期刊
Issue time：2007年
Well-defined ethyl cellulose-graft-poly(-caprolactone) (EC-g-PCL) graft copolymers were successfully synthesized via ring-opening polymerization (ROP) of -caprolactone (CL) with an ethyl cellulose (EC) initiator and a tin
2-ethylhexanoate (Sn(Oct)2) catalyst in xylene at 120 °C. Then, novel ethyl cellulose-graft-poly(-caprolactone)-block-poly(L-lactide) (EC-g-PCL-b-PLLA) graft-block copolymers were prepared by ROP of l-lactide (L-LA) with a hydroxyl-terminated EC-g-PCL macroinitiator and Sn(Oct)2 catalyst in bulk at 120 °C. Various graft and
block lengths of EC-g-PCL and EC-g-PCL-b-PLLA copolymers were obtained by adjusting the molar ratios of CL monomer to EC and the L-LA monomer to CL. The thermal properties and crystalline morphologies of EC-g-PCL and EC-g-PCL-b-PLLA copolymers were different from those of linear PCL. The in vitro degradation
rate of EC-g-PCL-b-PLLA was faster than those of linear PCL and EC-g-PCL due to the presence of PLLA blocks.