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Characterization of poly(silylenemethylene)s by positron annihilation lifetime spectroscopy. I.

✍ Scribed by Takuya Ogawa; Takenori Suzuki; Masashi Murakami

Publisher
John Wiley and Sons
Year
1998
Tongue
English
Weight
171 KB
Volume
36
Category
Article
ISSN
0887-6266

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✦ Synopsis

Amorphous and crystalline poly(silylenemethylene)s with the repeating PhRSiCH 2 (R : Me or Ph) units were characterized by positron annihilation lifetime spectroscopy (PALS) to gain insights into the molecular motions of these polymers. The temperature dependence of the ortho-positronium lifetime ( t 3 ) and intensity (I 3 ) was examined from 50 to 470 K for each sample. The glass transition temperature of each polymer was easily distinguished by a change in the slope of t 3 spectrum. Both polymers exhibited a steep drop of I 3 at 130-140 K being probably assignable to the transition arising from the motions of phenyl groups, which was almost undetectable by means of differential scanning calorimetry or dynamic mechanical analysis. Several other transitions of these polymers detected by PALS are also discussed.

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