Influence of ageing on the ordering phenomena of syndiotactic polystyrene
β Scribed by Francesco de Candia; Roberto Russo; Vittoria Vittoria
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 353 KB
- Volume
- 195
- Category
- Article
- ISSN
- 1022-1352
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β¦ Synopsis
Abstract
The crystallization from the glassy state of different samples of syndiotactic polystyrene (sPS) was investigated with different techniques, such as differential scanning calorimetry, infrared analysis, and polarized optical microscopy. The different samples of sPS were obtained by ageing the glassy sPS films at room temperature and at 70Β°C; the behaviour of these films was compared with that of the fresh sample, put at the crystallization temperature as soon as prepared. The temperature of crystallization was 120Β°C; at this temperature, besides the crystalline phase, a fraction of mesophase is formed. All the techniques investigated to follow the crystallization phenomenon show that the fresh sample crystallizes much sooner than the others; the sample aged at 70Β°C takes the longest time to crystallize, whereas an intermediate behaviour characterizes the sample aged at room temperature. This result was correlated with the initial structural organization of the glassy amorphous samples.
π SIMILAR VOLUMES
Fractionated syndiotactic polypropylene (sPP) samples with homogeneous tacticity were annealed at diΓΎ erent temperatures. The inΓ½uence of syndiotacticity and annealing temperature on the double melting peak phenomena were investigated. It is found that all fractions show double melting peaks at 75ΓC