Boron trifluoride-catalyzed degradation of poly-ε-caprolactone at ambient temperature

Poly-epsilon-caprolactone (PCL) can be accelerated to degrade in the presence of boron trifluoride at ambient temperature. The degradation behaviors were studied by using the inherent viscosity measurement, gel permeation chromatography (GPC), infrared analysis (FTIR), nuclear magnetic resonance analysis (NMR), and thermal analysis (DSC). With increasing the addition amount of boron trifluoride, the molecular weight of PCL decreases; the molecular weight distribution is broadened; and the degree of crystallinity of PCL increases at first at low BF(3) level, then decreases when BF(3) content exceeds to 2.64 wt%. The results of IR, (1)HNMR and GPC reveal that epsilon-caprolactone monomer does not occur and the main degradation products are the oligomers of PCL with low molecular weight. The mechanism for boron trifluoride-catalyzed degradation of PCL is discussed. (c) 2009 Elsevier Ltd. All rights reserved.