Film tear propagation resistance
Films tear propagation resistance was evaluated using the ASTM
D-1938 standard method with some modifications. At least ten
specimens of films based on TPS and TPS with 5% w/w talc particles
were assayed. According to the standard test method, samples
(25 75 mm) with a slit at 12.5mmwere prepared. Tensile tests by
pulling apart the specimen were performed in an Instron 3369
universal machine (Instron, USA) using a constant crosshead speed
of 250 mm/min and a gap between grips of 50 mm. Assays were
carried out at room temperature. Load-time curves were recorded
and average tear propagation force was determined, disregarding
the initial and final portions of the curves. In order to analyze
comparatively this mechanical property, tear propagation force
values were normalized considering film thickness.