Annealed PET films

Fig. 27. Difference spectra due to reversible thermal effects only. Difference spectra of highly annealed PET film between elevated temperatures and 30 °C on the basis of one-to-one subtraction, from 1650 on"1 to 1320 cm"1...

Sefcik et al. [3] studied quenched and annealed PET films with different crystallinities varying from 3-50%. They measured rotating-frame relaxation times of protons and carbons, Tip and Tip These parameters give information about molecular motions in the tens or hundreds of kilohertz range, which is a characteristic frequency range for many important motional processes in solid polymers. Sefcik et al. were particularly interested in relaxation times. Tip which, in principle, can provide information about molecular motions at specific sites within the polymer. A multiexponential behavior of the magnetization decay was observed. 

Fig. 7. Pole figures of (100) planes in stretched (4x1) and fixed annealed PET films, (a) Projection along MD (b) projection along TD. MD = machine direction, TD = transverse direction, and ND = normal direction.

Figure 4.10 Dependence of the density of PET films on annealing time and temperature film thickness, 0.25 mm My, 24600 g/mol initial density, 1.34g/ml [47], From Lin, S. and Koenig, J., J. Polym. Sci., Polym. Symp. d.,71,121-135 (1984), Copyright John Wiley Sons, Inc., 1984. Reprinted by permission of John Wiley Sons, Inc...

The PET was commercial (0.18 mm) Kodak ESTAR film base. The PE was commercial (0.10 mm) high density (HD) PE. To eliminate surface contamination, the polymer samples were ultrasonically cleaned in a series of solvents (heptane, dichloromethane, ethanol and ethyl acetate) and dried in a dry nitrogen atmosphere in a glove bag attached directly around the insertion probe of the spectrometer. Immediately after drying, the polymer samples were inserted into the preparation chamber of the spectrometer where they were evacuated to 5 x 10 9 Torr. The polymer samples were than annealed (PET 90° C, PE 60° C) for several hours to drive off any residual solvent, water, or adsorbed gases. 

PET Specimen. The PET plate of 2-mm thick and of very low crysal-linity was supplied by the Teijin Ltd.. By annealing the plate, the PET specimens of two different crystallinity ( 39 % and 55 % ) were obtained. On the other hand, the PET film of very high crystallinity ( 75 % ) was also used as the specimen wich was obtained by annealing a film of 0.5-inm thick and of 60 % crystallinity. The original film was produced by Toray Industries, Inc. The crystallinity of... 

PET is also used in film form (Melinex, Mylar) and as a molding material. The manufacture of PET film closely resembles the manufacture of fiber. The film is produced by quenching extruded sheet to the amorphous state and then reheating and stretching the sheet approximately threefold in the axial and transverse directions at 80-100°C. To stabilize the biaxially oriented film, it is annealed under restraint at 180-210°C. This operation increases the crystallinity of PET film and reduces its tendency to shrink on heating. The strength of PET in its oriented from is outstanding. 

We initially studied the polymer grafting employing model substrates, nanothick PET fibns deposited on a silicon wafer, to determine the optimal conditions for the surface modification of the membranes. Figure 1 shows the morphology of the PET films after annealing (140 C for 3 hours). The film imiformly covers the wafer at both micro- and nano-levels (Figure la). After the... 

Materials. PMMA (Polysciences, MW=60,000, Mw/Mn=1.10), PS (Aldrich, MW=44,000, Mw/Mn=1.10), and PET (Aldrich) films were prepared by spin coating (2000 rpm) 0.25 wt % polymer/solvent solutions onto silicon (100) wafers, which had a native oxide layer. Toluene was used as the solvent for PMMA and PS, and 2-chlorophenol was used for PET. Films were annealed at 100°C under vacuum ( 0.01 torr) for 2 hours and allowed to cool under vacuum. Experiments were performed within days of film coating, and 1 day or less after annealing. Film thicknesses were measured using ellipsometry (Sopra) and found to be approximately 21, 12, and 20 nm ( 5nm), for PMMA, PET, and PS, respectively. Film surfaces were homogeneous with rms roughnesses < 1 nm. 

Perkins W. Effect of molecular weight and annealing temperature on the oxygen barrier properties of oriented PET film. Polym Bull 1988 19 397. 

Figure 4, Factor analysis of annealed PET thin films, 1700-800 cm l.

Fig. 4. Spherulite in a thin, ice water quenched PET film annealed 6 days at 65 C. ...

The ratio method has been used to determine the pure spectra of the trans and gauche geometric isomers of PET [124]. The IR spectra of PET films that have been annealed for different times at 230 C are shown in Fig. 3.28. 

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