𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Thermal behavior of ferroelectric Polyamide 11 in relation to pyroelectric properties

✍ Scribed by L. Ibos; C. Maraval; A. Bernès; G. Teyssèdre; C. Lacabanne; S.-L. Wu; J. I. Scheinbeim


Publisher
John Wiley and Sons
Year
1999
Tongue
English
Weight
152 KB
Volume
37
Category
Article
ISSN
0887-6266

No coin nor oath required. For personal study only.

✦ Synopsis


The pyroelectric properties of oriented thin films of ferroelectric Polyamide 11 have been studied in the temperature range of Ϫ100°C up to ϩ140°C. The temperature dependence of the experimental pyroelectric coefficient has been analyzed. Three changes of slope of the pyroelectric coefficient are observed at Ϫ20, ϩ50, and ϩ100°C. The origin of the lower temperature event has not yet been defined. The upper transition is attributed to chain movements in crystalline regions, and more precisely, to a crystalline phase transition. The intermediate event is close to the glass transition temperature T g observed by DSC. It is attributed to the manifestation of the glass transition. Below T g , the variations of the pyroelectric coefficient are very small. For higher temperatures, it increases rapidly, attesting to a major contribution of secondary pyroelectricity and dimensional effects above T g . The breaking of hydrogen bonds occurring at the glass transition temperature observed on DSC thermograms does not affect pyroelectric properties. Pyroelectric properties are mildly reduced after annealing at temperatures up to ϩ140°C. A comparative study of oriented ferroelectric films prepared by quenching from the melt and nonoriented slowly cooled samples has been carried out by means of DSC.


📜 SIMILAR VOLUMES