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 by G(c), the strain energy release rate, and K-c, the stress intensity factor) was monitored during physical aging and during chemical degradation with methylamine. A change in the measured K-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.