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Figure 2.14. Kinetics of Isoramnetine consumption (1) and change of its rate at ultra-violet irradiation
(2).
Plane structure of HAC - L should facilitate aggregation of CC molecules, that leads to
very effective suppression of excited states. Obtained results give the reason to believe that
search for effective photostabilizers should be carried out among macrocyclic aromatic
compounds, having structure approaching to a plane.
Obtained effect of stabilization by hexaazocyclanes appeared to be effective and at
simultaneous action of mechanical load and ultraviolet light. As dependence of durability of
initial and dyed samples of CDA on the value of the load (Figure 2.13) at photomechanical
destruction shows, the durability of stabilized sample is higher than initial one by 1,3 times.
Important property of hexaazocyclanes is their ability to dye acetates into yellow, red,
brown coloures, since in this case additional introduction of dye is not required.
Method of determination of the mechanism of CC action was successfully used while
studying light-stabilizing action of isoramnetine. Isoramnetine (3, 5, 7, 4 - tetraoxy - 3 -
methoxyflavone) LXV, being industrial waste of solvent cake of fruits of sea-buckthorn, is
perspective as the dye of natural origin for products from cellulose acetate. Absorbing in
region λ=256nm close to CDA absorption, isoramnetine also has phonolic hydroxyls and
quinoid group in its structure, that supposes its high light-protective activity. It has been
found that lightfastness of CDA increases by 2,8 times at isoramnetine concentration equal to
3 mass %; polymer is being dyed steadily along the whole depth and intensity of painting is
proportional to the additive content. Changing of painting owing to additive consumption
(fading) is being observed during ultraviolet irradiation of CDA film, containing
isoramnetine. Constant of isoramnetine consumption (Figure 2.14, curve 1) has been defined
at initial section of kinetic curve of the change of optical density value. As it is seen from
Figure 2.13 (curve 2), the rate of additive consumption is inversely proportional to its
concentration. These results well agree with generally accepted information that at low
concentration molecules of the additive equalize among polymer chains forming monolayer
[175]. During increasing of additive concentration interaction forces between them overcome
interaction forces between additive and polymer, in our case - between isoramnetine and
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