Premium
The use of infrared spectroscopy for determination of polypropylene stereoregularity
Author(s) -
Burfield David R.,
Loi Patrick S. T.
Publication year - 1988
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1988.070360203
Subject(s) - crystallinity , analytical chemistry (journal) , polypropylene , infrared spectroscopy , infrared , fourier transform infrared spectroscopy , materials science , calibration curve , tacticity , calibration , annealing (glass) , absorption (acoustics) , spectroscopy , chemistry , optics , chromatography , polymer , composite material , physics , polymerization , organic chemistry , detection limit , quantum mechanics
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 −1 and 841 cm −1 as indices of isotacticity and bands at 1167 cm −1 and 973 cm −1 as internal references have been explored. Calibration curves relating various absorption ratios to isotacticity as measured by 13 C nuclear magnetic resonance are reported. The ratios A 998 /A 973 and A 841 /A 973 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 films by five instruments provide the calibrations: A 998 /A 973 = 1.08 ± 0.02 (mm)−0.15 ± 0.03; and A 841 /A 973 = 0.84 ± 0.06 (mm)−0.04 ± 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.