Synthesis of Dendrigraft Poly(ϵ-Caprolactone)s Using Side Hydroxyl Groups for the Grafting of Branch Chains

✍ Scribed by Juan Cheng; Xiujun Ling; Zhenlin Zhong; Renxi Zhuo

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 598 KB
• Volume: 32
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.201100465

✦ Synopsis

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.