| Title: |
Dielectric relaxation in vinylidene fluoride–hexafluoropropylene copolymers |
| Authors: |
Kochervinskii, Valentin V.; Malyshkina, Inna A.; Markin, Grigory V.; Gavrilova, Nadezhda D.; Bessonova, Natalia P. |
| Source: |
Journal of Applied Polymer Science ; volume 105, issue 3, page 1101-1117 ; ISSN 0021-8995 1097-4628 |
| Publisher Information: |
Wiley |
| Publication Year: |
2007 |
| Collection: |
Wiley Online Library (Open Access Articles via Crossref) |
| Description: |
The molecular mobility in copolymers of vinylidene fluoride–hexafluoropropylene VDF/HFP of 93/7 and 86/14 ratios has been investigated by means of broadband dielectric relaxation spectroscopy (10 −1 –10 7 Hz), differential scanning calorimetry DSC (−100 to 150°C), and of wide angle X‐ray diffraction WAXS. Four relaxation processes and one ferroelectric‐paraelectric phase transition have been detected. The process of the local mobility β‐ (at temperatures below glass transition point) is not affected by chemical composition of the copolymer and the formed structure. Parameters of segmental mobility in the region of glass transition (α a ‐relaxation) depend on the ratio of comonomer with lower kinetic flexibility. α c ‐relaxation is clearly observed only in VDF/HFP 93/7 copolymer, which is characterized by a higher crystallinity and a higher perfection of crystals of α‐ (α p ‐) phase. Diffuse order–disorder relaxor type ferroelectric transition connected with the destruction of the domains in low‐perfect ferroelectric phase in the amorphous regions has been detected for both copolymers. An intensive relaxation process (α‐process) was observed for both copolymers in high‐temperature region. DSC data shows that it falls on the broad temperature region of α‐phase crystals melting. It is considered to be connected with the space charge relaxation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| DOI: |
10.1002/app.26145 |
| Availability: |
https://doi.org/10.1002/app.26145; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fapp.26145; https://onlinelibrary.wiley.com/doi/pdf/10.1002/app.26145 |
| Rights: |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
| Accession Number: |
edsbas.9350E977 |
| Database: |
BASE |