| Autor: |
L.Yu. Zlatkevich, M.B. Konstantinopol'skaya, V.G. Nikol'skii, L.A. Osintseva |
| Rok vydání: |
1974 |
| Předmět: |
|
| Zdroj: |
Polymer Science U.S.S.R.. 16:3209-3217 |
| ISSN: |
0032-3950 |
| DOI: |
10.1016/0032-3950(74)90317-7 |
| Popis: |
It was shown that annealing “Moplen” isotactic polypropylene (PP) granules at temperature of 433–443°K and remelting reduced T g . Samples slowly cooled from melt have lower T g than quenched samples. By the crystallization of PP from 1% tetrachloroethylene solution samples were obtained with a ‘shish-kebab’ structure, which are characterized by a very low intensity β-maximum of radiothermoluminescence. Annealing ‘shish-kebab’ specimens at 433–453°K produces an intense β-maximum near 210°K. After heating these specimens to 455°K or higher temperatures spherulitic PP samples are obtained for which the shape of light emission curve agrees with that of the light emission curve of initial PP granules heated under the same conditions. It was shown that storing annealed PP speciments with a spherulitic structure at room temperatures is accompanied by a gradual increase of T g . It was assumed that the main cause of variation of T g of PP during heat treatment and storate is the formation of micropores and stressed sections in the amorphous phase of PP. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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