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found, as there is great difference in PA oxidation in the air or in oxygen atmosphere.
Investigation of thermal and photooxidative destruction of polyamide fabric in the presence or
absence of nitrogen oxides [9] is worth of paying attention to. Analyses of products at ultra-
violet light irradiation of ε - caprolactam in nitrogen oxide atmosphere in the absence of
oxygen shows presence of α-nitrocompounds, from which hypnitric acid splits out forming
caprolidenimide (hydrolyzed further intro amide ε-oxocapronic acid identified by 2,4-
dinitrophenylhydrazone) and ε - oxocapronic acid and its ester. Fabric irradiation in the
atmosphere with very large concentration of nitrogen oxides leads to the formation of
aldehydes, not found in the absence of nitrogen oxides. This shows that photolithic
destruction of PA in the atmosphere of nitrogen oxides is connected additionally with
reactions of splitting.
Mechanisms of aliphatic PA photooxidation under light action in the conditions of amide
group absorption [4] where studied. These reactions way flow under the action of short-wave
light which boundary at the Earth's surface is 290 nm. The main result of investigations was
discovery of the role of radical -
CONHCHCH
2
- (R
1
*),
being the precursor of all basic
products of alkylamide oxidation, for example,
RC*O
and
P
1
*,
formed at primary
photochemical process of photodissociation of amide bond according to the reaction:
Photolysis of PA-6 in solid state by light 253,7 nm is considered in works [7,8]; gas
composition of products is also investigated and this shows the presence of CO-groups.
Analysis of the products of nonsensibilized oxidation of PA and model amides proved
special role of radical P
1
* which, being formed by stage of H breaking from α- methylene
group, led to further autooxidation according to a following scheme [10]:
Р
1
Н
Wo
→ Р
1
*
(1)
Р
1
*
+ О
2
→ Р
1
О
2
*
(2)
Р
1
О
2
*
+ Р
1
Н → Р
1
ООН + Р
1
*
(3)
Р
1
ООН
hν
→ Р
1
О
*
+ О
*
Н
(4)
where W
0
- the rate of primary initiation; reaction (1) -reaction of initiation; (2-4)-
reactions of extension and branching of the chain.
It has been supposed that probability of radical decay of P
1
OOH is small and photodecay
of peroxides does not make considerable contribution to formation of radicals and products of
oxidation, and appearance of radicals P
1
* and P
1
O
2
in PA leads to efficient breakage of
macromolecules. Under some conditions there is possibility for quantitative transformation of
redicals P
1
* and P
1
O
2
and formation of P
1
* with quantitative yield from radicals of other
types.
While studying kinetics of photooxidation of polyundecanamide, substituted at nitrogen
atom by heptyl groups by 20 and 33% it has been found that accumulation of hydroperoxides
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