The raw DPF is cylindrical in shape and the fiber surface containing a large number of uncompleted grown fibers and impurities, as shown in Fig. 2 [7]. SEM micrographs show an
improvement in surface morphology after applying soda treatment. This improvement can be seen in Fig. 3. SEM micrographs
show that using soda treatment cleans the fiber surface of a large
amount of impurities and causes fibrillation. SEM micrographs
show that as soda concentration increases, number of pores increases on the fiber surface. This might be attributed to the severity
of reaction that increases as the soda concentration increases.
On the other hand, SEM micrographs show a huge distortion in
surface morphology after applying HCl treatment as can be seen in
Fig. 4. This might be attributed to the acid attack on fiber surface,
as HCl normality increases the surface distortion increases [18]