The arrow mark on the specimen indicated fibers orientation
of the extruded bio-composites as shown in Fig. 6b
and c. These fibers orientation also depend on the die
geometry. By changing die geometry the fibers orientation
could be changed to some extent. The end product exits
from the die this is why die is able to guide the melt flow
toward the exit path. As soon as the extruded materials
come from the die the soft materials were also stretched
for better fibers orientation. For instance, tapering shape
or straight channel makes difference in the fibers
orientation. Therefore, it is important to understand the
mechanism of fibers orientation in bio-composites through
extrusion technique. However, it is difficult to identify the
single fibers in bio-composites due to possibly less density
difference between PLA and wood fibers. Some void spaces
were observed in bio-composites for air trapping during extrusion. Fig. 6c also showed a 3D image of PLA/WP/bioadimide
bio-composites. There is no significant difference
in between Fig. 6b and c. No remarkable features were
noticed for bioadimide in bio-composites. However, a clear
difference was observed as compared to neat PLA. In conclusion,
the fibers can be aligned in different directions
by using different die geometry which could result in better
mechanical properties as expected.