| Autor: |
Wada, Hirokazu, Suzuki, Yasuo, Okamoto, Kenzo, Ishikawa, Masaru |
| Předmět: |
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| Zdroj: |
Polymer Journal; 2005, Vol. 37 Issue 12, p877-886, 10p, 8 Diagrams, 1 Chart |
| Abstrakt: |
The mechanism for the degradation of isotactic polypropylene (i-PP) due to treatment with heated chemical solutions was examined by three-point bending tests with U-notched bars in a plane strain state. When i-PP was treated with nitric acid solution, tie molecules that connect lamellar crystals were ruptured near the surface of the specimens. This resulted in a decrease in molecular weight and craze strength at the surface. Consequently, the surface craze was easily transformed into cracks. Since the edges of the cracks thus formed was sharp with small radii, the strong strain constraint caused stress concentration, resulting in a brittle fracture of the material. When i-PP was treated with sodium hydroxide and sulfuric acid solutions, increase in yield stress due to heat treatment was the dominant factor for decrease in toughness. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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