Enhancement of Physical and Mechanical Properties of Sugar Palm Fiber via Vacuum Resin Impregnation - Advanced Materials for Agriculture, Food and Environmental Safety - page 129

Figure 5.4 (a) Optical micrograph of control sample; (b) Optical micrograph of
UP-impregnated i bers (1000 mmHg); (c) Optical micrograph of UP-impregnated i bers
(900 mmHg); (d) Optical micrograph of UP-impregnated i bers (800 mmHg);
(e) Optical micrograph of UP-impregnated i bers (700 mmHg); (f ) Optical micrograph
of UP-impregnated i bers (600 mmHg); (g) Optical micrograph of UP-impregnated i bers
(500 mmHg).
Figure 5.4a clearly shows that the natural surface of the control sample
is dif erent from the impregnated i bers where the latter were enclosed
with the UP resin (Figs. 5.4b-g). It also shows that the UP-impregnated
i ber with an impregnation pressure of 500 mmHg (Fig. 5.4g) was fully
enclosed with the resin, while the i ber with an impregnation pressure of
1000 mmHg (Fig. 5.4b) seemed to be partially enclosed, where only a small
change in the i ber surface was observed. A higher degree of encapsulation
of this i ber (Fig. 5.4g) is also accompanied by the increase in impregnation
pressure that gives deeper penetration onto the i ber surface compared to
the lower pressure (Fig. 5.4b). h is allows resin molecules to be uniformly
distributed onto the i ber surface and more resin molecules are believed
to be embedded into the micropores (small holes that exist at the inter-
microi brillar region along the i ber). h is is because with the increase in
the number of resin molecules being embedded in the i ber surface, the