Improvement of processability of poly(epsilon-caprolactone) by radiation techniques

Improvement of processability of Poly(epsilon-caprolactone) (PCL) was achie ved by introduction of a branch structure using gamma-irradiation from a Co -60 source. Irradiated PCL has higher molecular weight by producting a bran ch structure. Hence, the irradiation at a lower dose, such as 3 Mrad, leads to a higher melt viscosity. The branched structure gave improved propertie s for dynamic viscoelasticit3r and elongational viscosity. High elongationa l viscosity was observed by entanglement due to branch chain formed during irradiation, and the elongational viscosity for 3 Mrad is higher than 1.5 M rad. Due to a higher elongational viscosity, PCL foam can be produced by a molding process. Foam produced from irradiated PCL pellets at 3 Mrad has ho neycomb-like structure, and the foam showed higher enzymatic degradation co mpared to film samples. (C) 1999 John Wiley & Sons, Inc.