title: Synthesis of dendrigraft poly(ϵ-caprolactone)s using side hydroxyl groups for the grafting of branch chains.
abstract: Dendrigraft poly(ϵ-caprolactone)s with high molecular weight and narrow polydispersity are synthesized via a convenient generation-growth approach. Copolymerization of ϵ-caprolactone (CL) and 4-(2-benzoxyethoxy)-ϵ-caprolactone (BECL) with stannous octanoate as a catalyst affords a functionalized poly(ϵ-caprolactone) (PCL) with benzyl-protected hydroxyl side groups. After removal of benzyl groups by palladium-catalyzed hydrogenolysis, the graft copolymerization of CL and BECL onto the hydroxyl-bearing linear polyester (zero-generation) affords the first-generation graft polyester. Further deprotection and graft polymerization cycles led to dendrigraft polyesters. Molecular weights are multiplied in each graft copolymerization. The second-generation dendrigraft poly(ϵ-caprolactone) has an M(w)  of 236 000 g·mol(-1)  and M(w) /M(n)  of 1.53.
authors.affiliation: Key Laboratory of Biomedical Polymers of Ministry of Education, Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China.
authors.forename: Juan
authors.initials: J
authors.lastname: Cheng
authors.forename: Xiujun
authors.initials: X
authors.lastname: Ling
authors.forename: Zhenlin
authors.initials: Z
authors.lastname: Zhong
authors.forename: Renxi
authors.initials: R
authors.lastname: Zhuo
mesh_terms: D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D015394:Molecular Structure; D008970:Molecular Weight; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D058105:Polymerization
chemical_list: D011091:Polyesters; C016240:polycaprolactone