Polymer degradation. V. Changes in molecular weight distributions during sonic irradiation of polyisobutene

✍ Scribed by Roger S. Porter; Manfred J. R. Cantow; Julian F. Johnson

• Publisher: John Wiley and Sons
• Year: 1967
• Tongue: English
• Weight: 269 KB
• Volume: 11
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1967.070110302

✦ Synopsis

Gel permeation chromatography was used to follow changes in the molecular weight distribution of a polyisobutene, initial = 466,000, during degradation induced by sonic irradiation.

In general, a steady decrease in molecular weight was observed, although a bimodal distribution was present after 20,000 sec. irradiation. Various measures of inhomogeneity, &?Jan, U , etc., were examined. The function, c , , / a w , where u,, is the standard deviation of the number distribution, is considered as a measure of the relative distribution.

It is shown to be almost constant throughout the degradation.

Seven samples taken a t times of 20&-163,500 see. were studied.

The energy-induced degradation of polymers is well known. 1-5 Studies on the changes in molecular weight distributions during degradation are not common, however, due to the tedious nature of determining such distributions. The advent of gel permeation chromatography has simplified measurement of molecular weight distributions. This paper presents results obtained in this manner to define changes in distribution during sonic irradiation of a polyisobutene solution.