One-step synthesis of hyperbranched biodegradable polymer

Hyperbranched poly(epsilon-caprolactone) (h-PCL) is synthesized via hybrid copolymerization of epsilon-caprolactone (CL) with glycidyl methacrylate (GMA) as the branching agent and (1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phophoranylidenamino]-2 Lambda 5,Lambda 5-catenadi(phosphazene) (t-BuP4) as the catalyst in one step. Proton nuclear magnetic resonance (H-1 NMR) and Fourier transform infrared (FTIR) spectroscopy show that the polymerization regarding the double bonds and ring-opening take place simultaneously. Size exclusion chromatography measurements with light scattering and viscosity detection indicate that the resultant polymer has a hyperbranched structure.