This work demonstrates that MMT acts as a major strengthening
component when added to soy-protein films since the strong
interactions that exist between the proteins and the clay occur
with the latter being thoroughly dispersed throughout the protein
matrix and to a high degree intercalated by the protein components
to the point of exfoliation. Also, the protein–protein,
protein–glycerol, protein–water and glycerol–water interactions
are modified by the presence of the layered silicate in the
formulation, as it is demonstrated by differential solubilization of
proteins of the nanocomposites films.
The improvements observed in the mechanical properties of
the soy-protein films and in their resistance to water upon
inclusion of MMT in their formulation is very likely related to
the degree of intercalation and consequent exfoliation of the two
components that results. This propitious restructuring of the
admixture of soy protein and MMT, in turn, can be attributed to
the use of the appropriate procedure to adequately disperse the
clay as well as the beneficial interactions generated between the
MMT and the soy protein within the films. That the uniform
dispersion of the laminas of clay within the matrix increases the
area of protein–clay contact further contributes to the efficient
functionality of these nanocomposite films. In comparison with
the control protein film Soy–MMT films showed an improvement
in their resistance to mechanical deformation, protein solubilization
in water and water vapor permeability, without affecting their
visual appearance. The nanocomposite film with the highest
content of clay analyzed conferred the most beneficial properties
on the resulting nanocomposites.