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sample increases almost linearly with the increase of temperature up to 390ºC, while
inhibiting effect in modified samples is observed up to 400-450ºC, HC-3 and HC-4 being an
exception. At much higher temperatures decay depth sharply increases.
Analysis of DTA, DTG, TG curves of modified and unmodified PETP - fibres has
shown, that though all additives - modifiers being used belong to one class of compounds,
they have different effect on PETP - fibre. Additives HC-2 and HC-1, being isomers of
phenyldiamine (HC-1 - para-product; HC-2 - meta-product), have different effect on PETP -
fibre. Additive HC-2 has greater plasticizing effect, then HC-1 (Table 29), though they have
small difference in structure.
Introduction of HC-1 into polymer increases temperature of polymer decay at isothermal
heating both in the presence of oxygen and without it. Additive HC-2 increases temperature
of PETP decay still more (almost by 30ºC higher, then HC-1). Hence, HC-2 protect PETP -
fibre from thermal and thermooxidative destruction more effectively.
Results of introduction of HC-3 and HC-4 are depart from general tendency of
hexaazocyclanes effect on PETP - fibre.
Introduction of HC-1, HC-2, HC-5, HC-6, HC-7 additives into PETP causes the increase
of polymer resistance to thermal and thermooxidative destruction. Addition of HC-3 and HC-
4 into PETP - fibre causes decrease of polymer resistance to these types of destruction.
Thus, all used additives may be devided into two groups: 1) increasing polymer
resistance to thermal and thermooxidative destruction; 2) decreasing polymer thermal
stability. Moreover, effect of additive on thermo- and thermooxidative stability will depend
on the length of conjugation chain in modifier's molecule.
Irradiation of PETP - fibres was carried out in the air for evaluation of dyes effect on
light stability of these fibres modified by hexaazocyclanes additives. Relative conservation of
initial specific viscosity was taken as criterion of ultra-violet irradiation effect.
Table 30. Change of specific viscosity of PETP solutions after ultra-violet irradiation for
24 hours
Additive and its concentration
in PETP, in mass %
Specific viscosity
Before irradiation
After irradiation
Conservation, %
Without additive
0,279
0,199
64,3
HC-1/1,0
0,335
0,241
71,8
HC-2/1,0
0,319
0,266
83,4
HC-3/1,0
0,312
0,194
61,5
HC-4/1,0
0,327
0,209
63,9
HC-5/1,0
0,325
0,236
72,6
HC-6/1,0
0,305
0,252
82,6
HC-7/1,0
0,346
0,256
74,0
Results of evaluation (Table 30) show, that little decrease of viscosity characteristics
takes place at irradiation in the air, but besides specific viscosity of fibres is more conserved.
HC-3 and HC-4 are the exception.
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