photolysis of poly-acyl styrene polymers
abstract
the following is a study of the long wave (wavelength >300 nm) photolysis
of a series of poly acyl styrenes, in particular, poly-p-acetyl-styrene (ppas), polyp-
propionyl-styrene (ppps), poly-o-acetyl-styrene (poas), poly-o-proponylstyrene
(pops).
all photoreactions are initiated from the carbonyl triplet. it is seen that in
the solid state, below tg the main photoprocesses that take place in all systems are norrish i cleavage and photoreduction. in addition, the ortho polymers have the
proper structure to allow for photoenolization. gas product analysis of these ortho
polymers, in the solid state below tg suggest evidence for ground state control.
transient spectroscopy does indicate the presence of enol formation in these ortho
polymers. viscosity studies on solutions showed that secondary reactions with
these polymers include competitive cross linking and chain scission. there is a
definite solvent effect observed for all of these systems and the solvent quality has
an effect on the balance of these secondary reactions. a detailed explanation of this
solvent effect is discussed.
collections
- retrospective theses [1604]