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concentration 3% of polymer mass does not influence CA durability after irradiation as well,
whereas introduction of XXXV and XXXVI almost completely conserves durability of
irradiated polymer.
Experimental data show that efficiency of light stabilization at photoageing depends on
the extent of conjugation of introduced CA-product-PAC [180].
On the basis of above mentioned it may be assumed that effect of light stabilization is
probably linked with the increase of electronic excitation transfer from polymer to PAC. And
it may be expected that the more complex is PAC molecule the more vibrating degrees of
freedom it has and the more is the observed effect of excitation suppression [180].
2.7.
L
IGHT
S
TABILIZATION OF
CDA
B
Y
N
ITROGEN AND
S
ULPHUR
C
ONTAINING
A
ROMATIC
C
OMPOUNDS
It is known that aromatic compounds containing heteroatoms of nitrogen may have light
stabilizing effect at polymers irradiation. Some derivates of carbazole, according to literature
and patent data, may be CC and antioxidants during oxidative destruction of polymers.
So, it seemed interesting to study the influence of substitutes in sulphuryl amides
concerning light stabilizing effect intensity. For this purpose we modified cellulose diacetate
(CDA) with the help of sulphuryl amide derivatives of carbazole and indan.
Among sulphuryl amide derivatives of indan the first to be synthesized was 5-indan
sulphonyl chloride - a result of indan and chlorosulphonic acid interaction. Then amines of
benzene series were acetated by previously produced 5-indan sulphonyl chloride. Some of the
appearing sulphuryl amides came through alkylation by dimethyl sylphate in sulphuryl amide
group. Carbazole derivatives were obtained by acetating of aniline with special carbazole
sulphanilchlorides according to the method [181].
These synthesized sulphuryl amide were used for cellulose diacetate (CDA) modification.
The obtained samples were formed as films and radiated by mercury vapour lamp in the air
during the period of 24 hours at T 35
0
С. Change of viscosity of cellulose diacetate solution
before and after irradiation was considered as the index of stabilizing effect of additions -
modifiers[182].
Tables 19 and 20 display the experimental results of sulphuryl amide derivatives of
carbazole and indan stabilizing effect.
Obtained data show high light-protective activity of studied compounds, which, perhaps,
may be either compared or exceed the activity of Tinuvine II.
Taking into account the fact that carbazolsulfonamide XXI-XXVIII (Table 19) absorb in
the same field as in CDA, then it may be supposed that stabilizing effect is caused by
“shielding” action.
In order to elicit the light stabilizing mechanism of the examined additions, modified
CDA- films were dissolved in acetonitrile before and after being radiated. The obtained
solutions were spectrographed in Ultra-violet (Figure 2.28-2.30).
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