The use of infrared spectroscopy for determination of polypropylene stereoregularity

✍ Scribed by David R. Burfield; Patrick S. T. Loi

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 743 KB
• Volume: 36
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1988.070360203

✦ Synopsis

This study examines the application of infrared (IR) spectrometry to the determination of polypropylene (PP) stereoregularity. The use of the absorption bands at 998 cm-' and 841 cm-' as indices of isotacticity and bands at 1167 cm-' and 973 cm-' as internal references have been explored. Calibration curves relating various absorption ratios to isotacticity as measured by I3C nuclear magnetic rmnance are reported. The ratios A,,/A,, and AM1/Ag3 are the most useful and provide linear correlations with isotacticity. The effect of instrument type on the calibration has been investigated for both dispersive and Fourier transform type IR spectrometers. For samples annealed at room temperature the average of measurements on the same set of PP f i l m s by five instruments provide the calibrations: Aw8/A973 = 1.08 + 0.02 (mm)-0.15 + 0.03; and A,,/A,, = 0.84 + 0.06 (mm)-O.M k 0.02. High temperature annealing increases the crystallinity of the samples and the corresponding value of the absorption ratio but is not necessary for obtaining reproducible calibration curves.