13C NMR spectra and magnetic relaxation times of isotactic polypropylene treated with fuming nitric acid

✍ Scribed by Hiroshi Tanaka

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 299 KB
• Volume: 31
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(94)00184-7

✦ Synopsis

3C NMR spectra and various magnetic relaxation times such as "C spin-lattice relaxation time, T,(C), 'H spin-lattice relaxation time in the rotating frame, T,,(H), and 'H spin-spin relaxation time in the rigid regions, T,(H), of isotactic polypropylene treated with fuming nitric acid were measured using the CP/MAS method. There are relatively small changes in T,(C) during the acid treatment but always two components of T, (C) were observed. In contrast to r,(C), T,,(H) increases significantly, after small decrease in the initial stage of the treatment, with increasing treatment time. T,(H) decreases steadily with increasing treatment time, though the change is small. These results indicate that the molecular mobility in the crystalline regions decrease with fuming nitric acid treatment but there are regions with different molecular mobility even in the crystalline core of isotactic polypropylene.

INTRODUCITON

Fuming nitric acid.