Mechanical behavior of poly(ethyleoe terephthalate) at cryogenic temperatures |
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| Authors: | C D Armeniades I Kuriyama J M Roe Eric Baer |
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| Institution: | 1. Division of Polymer Science , Case Western Reserve University , Cleveland , Ohio;2. Division of Polymer Science , Case Western Reserve University , Cleveland , Ohio;3. Department of Textile Engineering , Tokyo Institute of Technology , Tokyo , Japan |
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| Abstract: | The mechanical behavior of poly(ethylene terephthalate) (PET) was studied at temperatures from 4 to 300°K with a free oscillating torsion pendulum and an Instron tester. Torsion pendulum data show the presence of relaxation maxima below 80°K. Noncrystalline specimens show a small peak at 48°K (δ) and a shoulder at 8-12° K (?). A peak at 20° K is observed in crystalline samples, both oriented and unoriented. In addition drawn specimens show a pronounced peak at 48° K and the assymmetric maximum in the 100-240° K region is split into two peaks. The logarithmic decrement in the β-loss region decreases with increasing crystallinity and orientation, while the cryogenic loss peaks increase in intensity. Tensile tests with biaxially oriented and heat-set films show a twofold increase in elastic modulus and a tenfold increase in toughness at cryogenic temperatures when compared with “amorphous” PET. |
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| Keywords: | characterization chitosan composite microspheres fabrication gelatin |
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