DETERMINATION OF ISOTACTICITY OF POLYPROPYLENE IN 90-100 PERCENT RANGE BY INFRARED SPECTROSCOPY

An infrared method has been developed for the determination of the isotacticity of polypropylene in the 90–100% range. The method requires the annealing of thin films at 165–167°C. for 3 hr. in an inert atmosphere, followed by slow cooling to room temperature. For approximate answers the ratio of the intensity of the 10.00 μ band to that of the 10.27 μ band can be reported as the fraction of isotactic material. Better results are obtained, however, by using Figure 2 as a calibration curve and reading the values from it. Copyright © 1969 John Wiley & Sons, Inc.