The reason for this can be nanofiber agglomerates with higher CNF
contents, as dispersion of nanosized reinforcement in the
matrix polymer is the main problem in melt compounding
of nanocomposites [9,19]. Nevertheless, with the addition
of 10 wt.% of CNF, the strength of a neat thermoplastic
starch nearly doubled (8.8 and 16.4 MPa). The Young’s
modulus increased linearly with the increasing cellulose
nanofiber content, and the material containing 20 wt.% of
CNF had the highest modulus of elasticity.When compared
to the neat thermoplastic starch, the modulus increased
from 455 to 1317 MPa (190%) with the addition of
20 wt.% cellulose nanofibers. As expected, the elongation
at break reduced with the addition of cellulose nanofibers
(Table 1, Fig. 3).