Abstract
The photo-oxidation and the photo-dehydrochlorination of a series of PVC samples having different isotactic contents have been studied in the presence of oxygen. The build-up of carbonyl groups was found to decrease as the isotactic content was increased. Conversely, the dehydrochlorination quantum yield appeared to increase linearly as the isotactic content increased. It is proposed that the former result is due to a less favoured hydrogen abstraction reaction at the isotactic triads, resulting from a higher shielding of the hydrogen atoms at CHCl groups. The latter result is associated with both the occurrence of some chlorine atoms of low dissociation energy located at a definite type of isotactic triad and the favoured hydrogen abstraction reaction at the CH 2 group in syndio and heterotactic triads. The conclusions are discussed on the basis of the local conformations of the various triads. In particular, the role of the isotactic GTTG − triad conformation in the mechanisms above is emphasized.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
