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Characterization of uniaxially oriented isotactic polypropylene films using sonic velocity measurements
Author(s) -
Ibrahim A. Mahammad,
Wedgewood Alan R.,
Seferis James C.
Publication year - 1986
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760260903
Subject(s) - materials science , shear (geology) , shear modulus , composite material , ultimate tensile strength , tacticity , shear stress , polypropylene , polymer , polymerization
A simple and useful experimental method has been developed for obtaining shear compliance properties for film samples using sonic velocity measurements at room temperature. In this method, the transmit and receive transducers were aligned in such a way that a shear wave was generated and transmitted through the sample. The method was used to determine the in‐plane shear compliance properties of three well characterized uniaxially oriented isotactic polypropylene films with draw ratios of 1.2, 4, and 6 respectively. It was observed that shear velocities at angles 0 through 45° were symmetrical to those from 90 through 45°. Further, as the draw ratio of these film samples increases, the determined sonic shear compliance in the draw direction decreased linearly. In addition to he shear data, the in‐plane tensile compliance data were also determined for these three films for comparison. Collectively, these sonic tensile and shear data were analyzed to evaluate the four in‐plane material compliance constants, S 33 , S 22 , S 44 , and S 23 , required to characterize a film in plane stress. Finally, a previously developed two parameter model was used to predict both the shear and tensile sonic modulus properties based on orientation parameters and intrinsic properties of isotactic polypropylene. The predicted properties agreed reasonably well to the experimental data generated for these film samples in spite of the fact that the two parameter model assumes the in‐plane shear compliance to be a constant independent of the test angle.