Biomedical Engineering Reference
In-Depth Information
9.20
Aging kinetics of SC nanocomposites with 20% PE content [21].
12K respectively (Fig. 9.20). These results confirm the supposition that,
even at ambient temperatures, the process of intercalation of macromolecule
fragments into the layered structure of ceramic grains takes place (albeit
slowly), leading to the formation of local nanocomposites.
9.8.2 Aging of the SC characteristics of polymer-ceramic
nanocomposites with Mn, Co, Zn and Ni
Samples of metal-containing SC polymer-ceramic nanocomposites with
various metal polymers were used to investigate the effects of aging. The
results of measurements of SC nanocomposite characteristics before and
after aging, in the course of 1 year, are given in Table 9.12. It can be seen
that during aging of Mn-, Co-, Zn- and Ni-containing polymer-ceramic
nanocomposites,
Т
c
increased by 1-3K, while the SC transition width
narrowed down to 4-6K. There are, as yet, no reasonable explanations for
this.
9.9 Conclusions
The superconducting (SC) characteristics of polymer-ceramic composites
are determined by two main competing factors.
1. Interaction of the elements of the binder macromolecule with the
surface of the ceramic. Further intercalation of these elements into the
interstitial layer of the ceramic causes some elevation of T
c
(by 1-3K)
of the composites compared with the initial ceramic.
2. The stability of the polymeric binder against thermo-oxidative
destruction via macromolecule disintegration (for example as a result
