title: Property development for biaxial drawing of ethylene-tetrafluoroehtylene copolymer films and resultant fractural behavior analyzed by in situ X-ray measurements.
abstract: The property development of the ethylene-tetrafluoroethylene copolymer (ETFE) membrane induced by simultaneous biaxial drawing was investigated. Commonly, tensile strength can be increased by drawing; conversely, tear resistance decreases. In this study, the balance between tensile strength and tear resistance for the resultant ETFE membrane was optimized achieved by a combination of lamination of low molecular weight (LMW) and high molecular weight (HMW) layers and subsequent biaxial drawing. The structural factor determining tear resistance of these biaxially drawn membranes was determined based on in situ small-angle X-ray scattering (SAXS) measurement during tensile deformation simulating tearing tests. Lozenge shaped scattering, which indicated inclined lamellae, was observed during such tensile deformation of the resultant membranes. Remarkably, this inclined lamellar structure was observed for the pure LMW membrane; however, it also appeared at the interface between LMW and HMW layers within biaxially drawn membranes. For the membrane exhibiting the highest tearing strength, the fraction of such inclined lamella increased up to the critical strain corresponding to the actual sample breaking. These results confirm that the inclined lamellar structure absorbed strain during membrane tearing.
authors.affiliation: †Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Uehara
authors.affiliation: †Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Ono
authors.affiliation: †Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kakiage
authors.affiliation: †Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Sakamura
authors.affiliation: ‡Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Masunaga
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Yukawa
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Higuchi
authors.affiliation: ∥AGC Chemicals Americas, Inc. Exton, Pennsylvania 19341, United States.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kamiya
authors.affiliation: †Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamanobe