Biomedical Engineering Reference
In-Depth Information
Figure 1. The dependence of the change of the molecular mass of the polymethylacrylate from the time
of the fungus A.terreus effect on the hybrid block-copolymer CHITOSAN-МА: 1-control, 2- the films
were placed under the agar medium of the fungi culture, 3- the films were placed on the fungi culture
([МА]/[ glycosamine]= 3,3 mole/base-mole).
The effect of the metabolism products of the fungi Aspergillus terreus upon the physical-
mechanical properties of the films is inconsiderable (the sample was placed under the agar
medium of the fungi culture). The exposition results in case with the grafted copolymer differ.
The objective of the given experiment series was to study the physical-mechanical properties
of the film samples under the effect of Penicillium cyclopium upon the films placed on fungi
culture and under the effect of inoculation of the spore suspension upon the film samples
(suspension variant). In the two variants both the strain at failure and failing stress properties
decreased 1.5 times. It was noticed that the given decrease was observed within the first six
weeks. After that period no changes in the physical-mechanical properties are observed. It
turned out that a considerable influence upon the physical mechanical film properties was not
only the metabolism of the fungi itself but simultaneous effect of the fungi life activity
products (suspension variant).
The change in the physical-mechanical film properties is connected with the destruction
the (co)polymer structure. The fungi hyphae penetrate into the polymer film and destroy
gradually not only its supramolecular structure but also its macrochain structures.
Figure 3 shows the photographs of the results of the effect of the micromycetes upon the
films after 2 and 12 weeks which give an opportunity to visually estimate the bioconversion.
It can be clearly seen in the photographs that all the samples placed on the fungi culture are
almost completely covered with fungi hyphae after 12 weeks. The samples placed under the
agar medium of the fungi culture have even colouring probably due to the chemical
interaction of the fungi life activity products with the film components which, as it was said
previously, which also tells on their physical-mechanical properties.
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