| Autor: |
Ye.A. Sidorovich, N.S. Surkova, G.M. Tolstopyatov, Ye.V. Kuvshinskii, G.T. Tkachenko, A.I. Marei |
| Rok vydání: |
1974 |
| Předmět: |
|
| Zdroj: |
Polymer Science U.S.S.R.. 16:1434-1444 |
| ISSN: |
0032-3950 |
| DOI: |
10.1016/0032-3950(74)90405-5 |
| Popis: |
A dynamic mechanical method and electron microscopy have been used to study butadiene-styrene (BDST) thermoplastic elastomers of different compositions. The effect of the number of blocks present in the polymer chains at a fixed composition and molecular weight on the properties of these block copolymers has been established. The minimal block dimensions at which the polymers would behave like random copolymers have been estimated. Three-block copolymers with 40% styrene were found to have decreasing elasticity and loss moduli when the molecular weight increased from 7 × 104 to 65 × 104, while the tensile strength passes through a maximum. The electron microscopic studies showed laminar structures to form in the block copolymers, in which the molecular weight changed from 7 × 104 to 17 × 104. When the latter increased to 65 × 104, the macromolecular structure changes from the laminar to the globular. The method of sample preparation (from the melt or solution) greatly affected the mechanical properties and morphology of the copolymers with a large molecular weight. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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