title: Syntheses, characterization, and in vitro degradation of ethyl cellulose-graft-poly(epsilon-caprolactone)-block-poly(L-lactide) copolymers by sequential ring-opening polymerization.
abstract: Well-defined ethyl cellulose-graft-poly(epsilon-caprolactone) (EC-g-PCL) graft copolymers were successfully synthesized via ring-opening polymerization (ROP) of epsilon-caprolactone (CL) with an ethyl cellulose (EC) initiator and a tin 2-ethylhexanoate (Sn(Oct)2) catalyst in xylene at 120 degrees C. Then, novel ethyl cellulose-graft-poly(epsilon-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 degrees 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.
authors.affiliation: Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Weizhong
authors.initials: W
authors.lastname: Yuan
authors.forename: Jinying
authors.initials: J
authors.lastname: Yuan
authors.forename: Fengbo
authors.initials: F
authors.lastname: Zhang
authors.forename: Xuming
authors.initials: X
authors.lastname: Xie
mesh_terms: D002384:Catalysis; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D046529:Microscopy, Electron, Transmission / Q000379:methods; D015394:Molecular Structure; D009947:Organotin Compounds / Q000737:chemistry; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D012680:Sensitivity and Specificity; D013696:Temperature
chemical_list: D009947:Organotin Compounds; D011091:Polyesters; D011108:Polymers; C505727:poly(epsilon-caprolactone-co-lactide); C013517:ethyl cellulose; D002482:Cellulose