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obtained during introducing 0,25-0,5 mass % of dye into reactive mass both at the stage of
polymerization and directly into polymer melt.
Table 4 presents data on conservation of molecular mass of the crumb of dyed and
undyed PCA samples before and after irradiation, and this shows great increase of
photooxidative stability of dyed PCA samples.
Table 4. Conservation of molecular mass of synthesized PCA stabilized by XLY
compound after 10-hours irradiation by mercury-quartz lamp
Additive
concentration
%
[ή]
Molecular mass
Conservation of
molecular mass,
%
A number
of break
Before
irradiation
After
irradiation
Before
irradiation
After
irradiation
-
0,66
0,44
21000
12000
59,5
0,76
0,25
0,62
0,51
18600
14500
77,9
0,28
0,50
0,61
0,53
18200
15200
83,5
0,20
1,00
0,59
0,58
17500
17100
97,8
0,02
2,00
0,60
0,57
17800
16700
93,7
0,07
5,00
0,45
0,41
12300
10900
88,7
0,13
It should be noted that in the process of dissolving irradiated polymer in H 2 SO 4 and m
- cresol formation of insoluble products was not found, though data [128] obtained during
irradiation of PCA film in vacuum by complete spectrum of the lamp PRK-2 at 30 0 C for 10
hours showed the decrease of PCA solubility by 13% in m-cresol.
Figure 1.4. Dependence of the number of breaks (3) of PCA macromolecules on additive concentration.
As it was mentioned earlier, diffusive restruction of oxygen penetration into polymer
matrix might play here a great role. That is why diffusive factor may be ignored at small size
of particles of polymer crumb or small thickness of obtained PCA fibres.
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