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Titolo:
Real-time FTIR and WAXS studies of drawing behavior of poly(ethylene terephthalate) films
Autore:
Middleton, AC; Duckett, RA; Ward, IM; Mahendrasingam, A; Martin, C;
Indirizzi:
Univ Leeds, IRC Polymer Sci & Technol, Leeds LS2 9JT, W Yorkshire, EnglandUniv Leeds Leeds W Yorkshire England LS2 9JT S2 9JT, W Yorkshire, England Univ Keele, Dept Phys, Keele ST5 5BG, Staffs, England Univ Keele Keele Staffs England ST5 5BG s, Keele ST5 5BG, Staffs, England
Titolo Testata:
JOURNAL OF APPLIED POLYMER SCIENCE
fascicolo: 10, volume: 79, anno: 2001,
pagine: 1825 - 1837
SICI:
0021-8995(20010307)79:10<1825:RFAWSO>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
STRAIN-INDUCED CRYSTALLIZATION; POLY(ETHYLENE-TEREPHTHALATE) FIBERS; CONFORMATIONAL-CHANGES; MOLECULAR-ORIENTATION; PET; SCATTERING;
Keywords:
FTIR; WAXS; drawing behavior; poly(ethylene terephthalate) (PET) films;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Ward, IM Univ Leeds, IRC Polymer Sci & Technol, Leeds LS2 9JT, W Yorkshire, England Univ Leeds Leeds W Yorkshire England LS2 9JT Yorkshire, England
Citazione:
A.C. Middleton et al., "Real-time FTIR and WAXS studies of drawing behavior of poly(ethylene terephthalate) films", J APPL POLY, 79(10), 2001, pp. 1825-1837

Abstract

The development of molecular orientation and crystallization was studied during uniaxial drawing of poly(ethylene terephthalate) (PET) films, which was immediately followed by subsequent taut annealing at the drawing temperature. The behavior was monitored in real time throughout the drawing and annealing using dynamic FTIR spectroscopy and in situ WAXS measurements usingthe Daresbury Synchrotron Radiation Source. Films were drawn at 80 and 85 degreesC at varying strain rates (0.001-0.7 s(-1)). The true stress-strain behavior was determined at each of the drawing conditions and the density and optical anisotropy of unloaded samples was measured. The IR spectra wereanalyzed using curve reconstruction procedures developed previously, and they showed that orientation of the phenylene groups and the trans glycol conformers occurred before significant gauche-trans conformational changes could be seen. The onset of crystallization, defined as the point that the crystalline 105 reflection could be first observed using WAXS, was not found to correlate with any specific change in the proportions of trans and gauche isomers nor with any feature on the stress-strain curve. However, it was clear that, for these comparatively low strain rates, crystallization occurred during the drawing process while the crosshead was moving and the draw ratio was increasing. The orientation of the crystallites was calculated from the (1) over bar 05 reflection observed in a tilted film, transmission geometry. The crystallites were found to form at a draw ratio of about 2.5 with high orientation values (P-2> 0.8) that increased during drawing and annealing to P-2 values of 0.95, irrespective of the drawing conditions. Semiquantitative measurements of crystallinity showed that the fraction of crystalline material that developed during drawing decreased with increasing strain rate. (C) 2001 John Wiley & Sons, Inc.

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Documento generato il 30/10/20 alle ore 09:11:55