THE EFFECT OF ANNEALING ON THE STRUCTURE AND PROPERTIES OF ISOTACTIC POLYPROPYLENE FILMS

Citation
Wj. Okane et al., THE EFFECT OF ANNEALING ON THE STRUCTURE AND PROPERTIES OF ISOTACTIC POLYPROPYLENE FILMS, Journal of macromolecular science. Physics, B34(4), 1995, pp. 427-458
Citations number
46
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Polymer Sciences
ISSN journal
0022-2348
Volume
B34
Issue
4
Year of publication
1995
Pages
427 - 458
Database
ISI
SICI code
0022-2348(1995)B34:4<427:TEOAOT>2.0.ZU;2-S
Abstract
The effect of annealing on the structure and properties of two polypro pylene (PP) films, one displaying the monoclinic or-structure and the other the quenched structure, has been investigated using a combinatio n of differential scanning calorimetry (DSC), small- and wide-angle x- ray scattering (SAXS and WAXS), and uniaxial tensile testing. It has b een established that upon heat treatment at temperatures >60 degrees C there is an increase in the yield stress of both films, and that this increase can be attributed to an increase in the size and perfection of the crystalline regions. An attempt has been made to quantify the y ield mechanisms occurring within these films. It has been found that a good correlation could be obtained between the experimental results a nd a crystal plasticity mechanism involving the thermal activation of screw dislocations with their Burger vectors parallel to the chain dir ection.