13C-NMR spectra of isotactic polypropylene film during stretching and shrinkage

✍ Scribed by Hiroshi Tanaka; Hiromichi Harada

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 263 KB
• Volume: 27
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(91)90116-6

✦ Synopsis

The line-shape of ~3C-NMR spectra of highly crystalline isotactic polypropylene film during stretching and subsequent shrinkage was investigated. Well-resolved splittings of the resonance peaks of methylene and methyl carbons before stretching disappear with increasing stretching ratio (2 > 10) and recover, although incompletely, by the subsequent shrinkage. Structural properties such as crystallinity and d-spacings of ( ) and ( ) planes were also measured during stretching and shrinkage. The crystallinity decreases with increasing stretching ratio. When the sample of 2 = 10 was shrunk, ca 60% of AXe was recovered, where AXe is the difference between the crystallinity before and after stretching. The d-spacings of ( ) and ( ) planes slightly change during stretching and recover almost to the initial values as a result of the shrinkage.