Schmelz‐ und kristallisationserscheinungen bei makromolekularen substanzen. VI. Ergebnisse der röntgenklein‐ und weitwinkeluntersuchungen an polyglykolterephthalat (terylen).

Abstract

ZUSAMMENFASSUNG:Rontgenographische Untersuchungen ergaben, daB die Kleinwinkelperiode im Verlauf der Nachkristallisation mit zunehmendem Kristallisationsgad abnimmt. Ferner steigt nach dem Erhitzen einer bei 140 "C auskristallisierten Probe a d eine hohere Temperatur die Kleinwinkelperiode zunachst stark an und nimmt wihrend der anschlieBenden Neukristallisation wieder etwas ab. Die Deutung dieser experimentellen Ergebnisse wird diskutiert, wobei der EinfluB des Bausteinfaktors beriicksichtigt wird.Weitwinkeluntersuchungen zeigten, daB bei der isothermen Kristallisation der Kristallisationsgrad zwar zunimmt, die Ordnung in Kettenrichtung aber nicht verbessert wird; diese hangt offenbar nur von der Kristallisationstemperatur ab. Beim partiellen SchmelZen und anschlieBender Kristallisation bei tieferer Temperatur ist stets eine Verschlechterung der molekularen Ordnung -im besonderen in Kettenrichtung -festzustellen. SUMMARY:X-ray investigations show that the small angle period decreases with increasing crystallinity in the course of secondary crystallization. When a sample previously crystallized at 140 "C. is heated to a higher temperature, the small angle period firstly increases and thereafter decreases during the following new crystallization. The interpretation of these experimental results is discussed.It is shown by X-ray wide angle scattering. that the order in chain direction is not improved with increasing crystallinity during isothermal crystallization. This order obviously depends only on the temperature of crystallization. After partial melting followed by a crystallization at a lower temperature the molecular order particular in chain direction -becomes less perfect.

Structure and properties of polyethyleneterephthalate crystallized by annealing in the highly oriented state

“…As shown in Fig. 5, no systematic change in tile long spacing, L, can be observed using annealing temperatures of 240 and 255 ~ C. This observation is in remarkable contrast to the data of Zachmann and Schmidt [19] who observed a Because of the intensity scale in Fig. 3 the maximum in the scattering curve of the 120 ~ C sample does not emerge, but the long spacing can be determined from the original intensity data.…”

“…In the case of undrawn PET a decrease in L during the secondary crystallization has been observed [19]. As a comparison of the scattering curves in Figs.…”

On the sensitivity of dimensional stability of high density polyethylene on heating rate

“…In fact at high heating rate the spherulites have not enough time to rearrange unlike at low heating rate. This behavior can be a result of more recrystallisation (or post crystallization) of polymer [21][22]. Our results differ from those presented by other investigators is that we take into account the effect of both temperature and heating rate on SCTE.…”

The Effect of Molecular Weight Distribution on the Physical Properties and Morphology of Polypropylene Stretched Tape

“…The differences between the annealed and unannealed tapes are insignificant, 2-4 angstroms. Annealing usually results in lamellar thickening [5,[11][12][13] and relaxation of the orientation in the amorphous material; two offsetting effects on the LPS. This may be why the changes in LPS appear to be independent of the annealing process.…”