The results of DMTA for the PA-6 and PA-6/silver–zinc
crystals casings are shown in Table 3. Note that there is no
significant changing ( p > 0.05) in the Tg values of PA-6 with the
inclusion of silver–zinc crystals in the matrix. It can be seen
significant differences ( p 0.05) only between PA-6 and PA-6/
silver–zinc chicken sausages casings for the case of loss
modulus; the microcomposite films exhibited higher values
than PA-6, although this difference does not have practical
importance and suggest that the addition of the antimicrobial
component did not change these thermodynamic properties
of the packing material. All casings, control and active for
chicken and beef sausages, presented a typical dynamic
mechanical thermogram of polyamides, reporting the Tg of the
polymer in the maximum of the loss modulus and Tan Delta
curves, whereupon it was found that the inclusion of silver–
zinc crystals did not alter the properties of the films.
With the purpose of assess the distribution of the silver–
zinc crystals on the surface of PA-6 microcomposites, SEM
images are presented in Fig. 3. Agglomeration may be observed
from some microparticles forming secondary structures, but
in general the silver–zinc microparticles are well dispersed in
the polymeric material. The tactoid structure predominating