Rheo-optical studies of high polymers. IX. A study of deformation process of low-density polyethylene by simultaneous measurements of stress, strain, and infrared absorption
| Autor: | Shigeharu Onogi, Tadahiro Asada |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Journal of Polymer Science Part C: Polymer Symposia. 16:1445-1455 |
| ISSN: | 1935-3065 0449-2994 |
| DOI: | 10.1002/polc.5070160322 |
| Popis: | As one of rheo-optical methods to study the relation between structure and mechanical properties of high polymers, simultaneous measurement of the stress, strain, and IR absorption during the experiments involving stress relaxation and stretching at constant rate of strain has been developed. The IR absorbances measured with radiations, both unpolarized and polarized, for the crystalline bands near 725 cm. −1 of low-density polyethylene can attain their equilibrium values in a time shorter than 1 sec. during the stress relaxation, being consistent with the results obtained by the dynamic birefringence method. In the case of stretching at a constant rate of strain, the orientation functions of crystallographic axes can be obtained as functions of strain from the dichroic ratio. The orientation function vs. strain curves and the corresponding stress-strain curve for low-density polyethylene film in the machine direction are divided into four regions according to the magnitude of strain. On the basis of comparison of these curves with each other and by employing the current model of folded chains, an interpretation has been given of the above four regions in the stress-strain curve. |
| Databáze: | OpenAIRE |
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