Evaluation of the Puncture Behavior, Tear Behavior, and Essential Work of Fracture of iPP Film with Continuous and Ordered β‑Transcrystallinity.

This study investigates the puncture and tear fracture behavior of isotactic polypropylene (iPP) films with an ultrahigh fraction of continuous and ordered β-transcrystallinity (β-TC), in comparison with α-spherocrystal, α-transcrystallinity, and β-spherocrystal films. In puncture tests, where the loading is applied perpendicular to the film surface, the β-TC film withstood a displacement exceeding 10 mm without rupture, absorbing substantially more energy than the other films. In tear tests, where the loading is applied parallel to the film surface, the β-TC film displayed pronounced ductile tearing characteristics, including significant yielding and strain-hardening, indicative of superior in-plane tear resistance. Quantitative evaluation using the Essential Work of Fracture (EWF) method further revealed that the specific essential work of fracture (we)a measure of intrinsic fracture toughnessreached 38.229 kJ/m2 for the β-TC film, representing an 81.39% enhancement over the β-spherocrystal film. These findings systematically establish a clear correlation between the ordered β-transcrystalline morphology and the multidimensional fracture resistance of iPP films, highlighting a promising strategy for the design of high-performance polymer films.