Monitoring degradation of poly(hydroxybutyrate) by fracture toughness measurements

The fracture behavior of poly(hydroxybutyrate) is described in terms of classical fracture mechanics. The fracture toughness (measured byG _c, the strain energy release rate, andK _c, the stress intensity factor) was monitored during physical aging and during chemical degradation with methylamine. A change in the measuredK _c value was found after degradation by methylamine which does not seem to be due solely to the measured thickness changes. The work lays the foundation for studies monitoring changes in fracture behavior during environmental degradation.Presented at the 4th International Workshop on Biodegradable Plastics and Polymers, October 11–14, 1995. Durham, New Hampshire.