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Coextrusion of it‐polypropylene film
Author(s) -
Kunugi Toshio,
Yoneyama Yuko,
Porter Roger S.
Publication year - 1990
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1990.070410302
Subject(s) - polypropylene , materials science , crystallinity , composite material , extrusion , modulus , dynamic mechanical analysis , viscoelasticity , superstructure , dispersion (optics) , nanocomposite , polymer , optics , structural engineering , physics , engineering
it‐Polypropylene films were coextruded by using dies of varying extrusion draw ratio (EDR) from 2–10. Among the resulting films, the film coextruded at EDR 9 possesses the most attractive superstructure and the highest modulus. The dynamic modulus at room temperature was 7 GPa and an α c dispersion peak occurred at 100°C in E″‐temperature curves, which is higher by about 20°C than that of the multistep zone‐drawn and zone‐annealed fibers previously reported. Further, to prepare films with higher draw ratio and higher modulus, repetition of the coextrusion was attempted. Consequently, the draw ratio and the E′ at room temperature reached 12 and 13 GPa, respectively. The present paper discusses changes in molecular orientation, crystallinity, uniformity of the superstructure, and dynamic viscoelasticity, with increasing of the used EDR and repeating the coextrusion with some combinations of EDR.