title: Direct cyclodextrin-mediated ring opening polymerization of ϵ-caprolactone in the presence of yttrium trisphenolate catalyst.
abstract: Unmodified β-cyclodextrin has been directly used to initiate ring-opening polymerization of ϵ-caprolactone in the presence of yttrium trisphenolate. Well-defined cyclodextrin (CD)-centered star-shaped poly(ϵ-caprolactone)s have been successfully synthesized containing definite average numbers of arms (N(arm) = 4-6) and narrow polydispersity indexes (below 1.10). The number-average molecular weight (M(n,NMR)) and average molecular weight per arm (M(n,arm)) are controlled by the feeding molar ratio of monomer to initiator. The prepared star-PCL with M(n,NMR) of 2.7 × 10(3) is in fully amorphous and that with M(n,NMR) of 13.3 × 10(3) is crystallized. In addition, the obtained poly(e-caprolactone) (PCL) stars with various molecular weights have different solubilities in methanol and tetrahydrofuran, which can be applied for further modifications.
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Yinghong
authors.initials: Y
authors.lastname: Zhu
authors.forename: Jun
authors.initials: J
authors.lastname: Ling
authors.forename: Zhiquan
authors.initials: Z
authors.lastname: Shen
mesh_terms: D002208:Caproates / Q000737:chemistry*; D002384:Catalysis; D003505:Cyclodextrins / Q000737:chemistry*; D007783:Lactones / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry*; D012995:Solubility; D015019:Yttrium / Q000737:chemistry*
chemical_list: D002208:Caproates; D003505:Cyclodextrins; D007783:Lactones; D009942:Organometallic Compounds; D011091:Polyesters; C016240:polycaprolactone; C121056:caprolactone; D015019:Yttrium; D000432:Methanol