Sequence distribution and intramolecular excimer formation in styrene-acrylonitrile copolymers

✍ Scribed by D.J.T. Hill; D.A. Lewis; J.H. O'Donnell; P.W. O'Sullivan; P.J. Pomery

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 508 KB
• Volume: 18
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(82)90135-5

✦ Synopsis

Abstraet--Styrene-acrylonitrile copolymers, like many other copolymers containing styrene, exhibit both normal and excimer fluorescence. We have shown that the ratio of the excimer to monomer fluorescence intensities in random styrene-acrylonitrile copolymers is linearly dependent upon the concentration of styrene-styrene bonds in the copolymer. This observation is consistent with a photophysical model which allows the energy absorbed by styrene units to migrate freely along the copolymer chain. Some of the energy is emitted in the form of normal fluorescence; some of the energy, trapped by neighbouring styrene-styrene pairs suitably oriented to allow excimer formation, is emitted as excimer fluorescence. The fluorescence characteristics of acrylonitrile-styrene copolymers are contrasted with those of methyl methacrylate-styrene copolymers, in which the methylmethacrylate sequences are believed to present partial barriers to energy migration along the copolymer chains.