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Titre du document / Document title

The crystal structure of polytetrafluoroethylene, forms I and IV

Auteur(s) / Author(s)

CLARK Edward S. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, ETATS-UNIS

Résumé / Abstract

Polytetrafluoroethylene (PTFE) is unusual among polymers in that it has four crystal phases, designated I-IV, with two of the phases (I, IV) incorporating substantial angular motion (librations) of linear segments within a precisely defined lateral lattice array. Data not included in the authors' earlier publications are presented to interpret two unsolved aspects of the crystal structure: 1) the narrow (11K) range of Form IV (I atm) and 2) the possibility of another transition in Form I. The existence of Form IV is attributed to an "energy well" from space group P3/. The molecular behavior in Form I is attributed to (L-R) molecular defects (changes in chirality) that increase rapidly in number and speed of translation along tire axis with increasing temperature.

Revue / Journal Title

Journal of macromolecular science. Physics    ISSN  0022-2348   CODEN JMAPBR 

Source / Source

Congrès
International Polymer Physics/Morphology Symposium, Champaign-Urbana, Illinois , ETATS-UNIS (08/04/2005)
2006, vol. 45, no 2 (230 p.)  [Document : 13 p.] (15 ref.), [Notes: Selected papers], pp. 201-213 [13 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Taylor & Francis, Philadelphia, PA, ETATS-UNIS  (1967) (Revue)

Mots-clés anglais / English Keywords

Review

;

Temperature effect

;

Polymorphic transformation

;

Crystalline structure

;

Tetrafluoroethylene polymer

;

Mots-clés français / French Keywords

Forme IV

;

Forme I

;

Article synthèse

;

Effet température

;

Transformation polymorphique

;

Structure cristalline

;

Ethylène(tétrafluoro) polymère

;

Mots-clés espagnols / Spanish Keywords

Artículo síntesis

;

Efecto temperatura

;

Transformación polimorfa

;

Estructura cristalina

;

Etileno(tetrafluoro) polímero

;

Mots-clés d'auteur / Author Keywords

polytetrafluoroethylene (PTFE)

;

crystal phases

;

libration

;

chirality

;

Localisation / Location

INIST-CNRS, Cote INIST : 13622 B, 35400015300891.0030

Nº notice refdoc (ud4) : 17710607



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