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Titolo:
Computer simulation of structure and ferroelectric phase transition of vinylidene fluoride copolymers. IV. The factors governing the ferroelectric phase transition of VDF-TrFE copolymers
Autore:
Abe, Y; Tashiro, K;
Indirizzi:
Osaka Univ, Grad Sch Sci, Dept Macromol Sci, Toyonaka, Osaka 5600043, Japan Osaka Univ Toyonaka Osaka Japan 5600043 i, Toyonaka, Osaka 5600043, Japan Toyobo Co Ltd, Res Ctr, Ohtsu, Shiga 5200292, Japan Toyobo Co Ltd Ohtsu Shiga Japan 5200292 Ctr, Ohtsu, Shiga 5200292, Japan
Titolo Testata:
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
fascicolo: 6, volume: 39, anno: 2001,
pagine: 689 - 702
SICI:
0887-6266(20010315)39:6<689:CSOSAF>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
TRIFLUOROETHYLENE COPOLYMERS; POLY(VINYLIDENE FLUORIDE); CURIE TRANSITION; CO-POLYMERS; FORM-I; TEMPERATURE; BEHAVIOR; TETRAFLUOROETHYLENE; DYNAMICS; DEPENDENCE;
Keywords:
vinylidene fluoride copolymer; ferroelectric phase transition; molecular dynamics simulation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Tashiro, K Osaka Univ, Grad Sch Sci, Dept Macromol Sci, Toyonaka, Osaka 5600043, Japan Osaka Univ Toyonaka Osaka Japan 5600043 , Osaka 5600043, Japan
Citazione:
Y. Abe e K. Tashiro, "Computer simulation of structure and ferroelectric phase transition of vinylidene fluoride copolymers. IV. The factors governing the ferroelectric phase transition of VDF-TrFE copolymers", J POL SC PP, 39(6), 2001, pp. 689-702

Abstract

A molecular dynamics simulation was performed to clarify the factors governing the ferroelectric phase transition of vinylidene fluoride-trifluoroethylene copolymers. The vinylidene fluoride (VDF) content dependence of the phase-transition temperature or the temperature of trans-to-gauche conformational change was investigated via models with VDF contents of 50, 70, and 100 mol %. The phase-transition temperatures of 70 mol % VDF models were higher than those of 50 mol % VDF models, consistent with experimental data. Poly(vinylidene fluoride) form I with 100% VDF showed the trans-to-gauche conformational change at a high temperature of about 600 K, although this temperature was tremendously higher than the melting point. The effects of theintermolecular and intramolecular interactions were also investigated. When only the van der Waals interaction was taken into consideration as an intermolecular interaction, the molecular chains in the cell rotated rigidly around their chain axes with the trans conformation kept. However, the consideration of only Coulombic interactions resulted in the collision of chainsbecause of the excessively strong attractive force. The transition behavior was governed by the balance among the torsional potential energy barrier of the skeletal chains, the intermolecular van der Waals interaction, and the Coulombic interaction between the atomic charges. Additionally, the introduction of head-to-head and tail-to-tail abnormal linkages into the molecular chains expanded the cell volume and lowered the phase-transition temperature. (C) 2001 John Wiley & Sons, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/04/20 alle ore 21:42:35