Essential work of fracture (EWF) analysis for compression molded alternating poly(propylene carbonate)

In this investigation. the main objective was to study the mechanical properties of alternating poly(propylene carbonate) copolymer (PPC). The PPC used in this study was derived from propylene oxide and carbon dioxide using zinc glutarate as catalyst. The molecular weight of the PPC copolymer used in this study has (M) over bar (n)similar to33,000. The synthesized PPC was compression molded into sheets of thickness similar to1 mm. The fracture toughness of the PPC films was determined using the essential work of fracture (EWF) technique, at a laboratory temperature of 20degreesC, and a loading rate of 1 mm/min. During the EWF measurement, a significant amount of plastic deformation has taken place around the initial ligament region. The measured specific total fracture work (w(f)) was observed to vary in a linear fashion with the specimen ligament (1), and hence satisfied the basic requirement for EWF analysis. The specific essential fracture work (w(e)) for the PPC film was measured to be 11.0 kJ/m(2). The PPC showed a prominent recovery behavior. The severely deformed region surrounding the fracture ligament was observed to recover completely 8 days after fracture testing.