Isothermal rupture characteristics of a plasticized poly(vinyl chloride) in the glass–rubber transition zone

Constant strain‐rate uniaxial extension tests to rupture were performed at 23°C on a plasticized poly(vinyl chloride) (PVC) in the glass‐to‐rubber transition zone, T g = −18°C, where experimental failure time t f is equal to or greater than material relaxation time τ. Range of strain rate is from 1.8 × 10 −4 to 1.8 × 10 −1 sec −1 . The rupture characteristics in stress/strain time space are analyzed on the three coordinate planes. Time and deformation separability are examined in a nonlinear‐constitutive relation. Rupture data on the coordinate planes are described by the Bueche‐Halpin theory in which time effects are considered through a small‐deformation viscoelastic property. Fracture surface morphology and separation processes in the crack tip are related to rupture characteristics.