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Figure 1 Results of DTA
1 – ITA-31; 2 – VP-1AP (OH –
); 3 – ITA-31+VP-1AP(OH –
); 4 – ITA-31+ VP-1AP(OH –
)+ELUR; 5 – VP-1AP (NO3
417
–
);6 – VP-1AP (I –
)
The thermal experiments have demonstrated that the IER containing chemical analogues of investigated
elements enter into chemical reactions with polyimide binders like ITA-31 and it is possible
in such a manner to produce the heat-resistant matrices for incorporation of the above elements in
the course of subsequent carbonization process. In the range of 600 - 1000°� no significant losses
of rhenium and europium are observed and only some marked losses of iodine occur due to lower
melting point of its compounds.
3.2 Synthesis of composites incorporating ITA-31 binder and elements under study
The technology for production of carbon-plastics elaborated in the previous works [4] involved the
ITA-31 synthesis, the procedure for impregnation of a required number of carbon-fabric layers, the
pressing at 300�� for 1 hour under excess pressure of 0.1 – 0.5 atm. The mass ratio between binder
and carbon fabric was 1:1.
The composite (prepreg) being converted into carbon-plastic state was then subjected to carbonization
in vacuum or inert medium in the temperature range of 20 - 600�� at a rate of 7 �/min. It should
be noted that both prepreg and carbon-plastic produced in accordance with this technology possess
high mechanical and thermal strength. The properties of the carbon-plastics produced by incorporation
of IER (for example VP-1AP) into their composition at various ratios between components are
shown in the Table 1.
As it is seen from the results obtained, the strength values of carbon-plastics remain rather high
over a wide range of ratios between ITA-31 and IER. These values meet the requirements of the
Russian and International standards for RAW incorporating matrices.
However, by using such carbon-plastic molding technique a partial loss of composite occurs due to
its flowing out of press mold. In production practice of carbon-plastics containing no harmful
chemical and radioactive substances these losses can be collected and returned into the process
without any radioactive substances these losses can be collected and returned into the process without
any technical difficulties. However, in the case of producing the carbon-plastics (matrices) containing
radioactive substances the composite flowing from press-mold may lead to non-controlled
contamination of equipment and work places.
Other variants of molding matrices were elaborated in this work, which could prevent the noncontrolled
losses of RAW during molding.
In the first case the preliminarily prepared prepreg containing ITA-31 and ELUR was crushed to
sizes of 5 – 10 mm and mixed on heating with the resin saturated by element being investigated. At