Enhancement of Physical and Mechanical Properties of Sugar Palm Fiber via Vacuum Resin Impregnation - Advanced Materials for Agriculture, Food and Environmental Safety - page 135

Properties

Shrinkage

Strength

MC (%)

0 30

FSP

Figure 5.10 Relation of shrinkage and strength of natural i ber upon FSP.

PF: y = 0.1666x + 2.8654
R 2 = 0.9846

UP: y = 0.1004x + 2.9629
R 2 = 0.9554

5

PF
UP

3.89 f

3.73 e 3.98 g

3.59 f

4

3.55 d

3.51 e 3.6 f

3.39 c

3.15 b

3.41 d

3.27 c

3.07 a

3.1 b

3

2

1

0

Control 1000 900 800 700 600 500

Impregnaton pressure (mmHg)

Figure 5.11 Tensile modulus of PF- and UP-impregnated sugar palm i bers at various
impregnation pressures.

modulus as the pressure increases. h e impregnated i bers became brittle
as impregnation pressure increased. h e opposite trend was obtained for
tensile strength where the PF-impregnated i bers showed a signii cantly
higher tensile modulus than UP-impregnated i bers, as observed in their
regression trends. It is also observed that the i bers reached a signii cant
maximum tensile modulus when impregnated at a pressure of 500 mmHg:
3.98 GPa (PF) and 3.60 GPa (UP). h ere was also no signii cant dif er-
ence in the tensile modulus of UP-impregnated i ber between pressures
of 600 and 500 mmHg. h e increase in brittleness, especially for the i ber
impregnated with PF, explains that less energy was absorbed before rup-
ture, which means a reduction in i ber toughness. h is information is vital
in designing materials used in structural applications where it is important
to produce a tough material as opposed to a brittle material.
As observed earlier in the stress strain curve, the elongation at break
of i ber at er impregnation was reduced considerably as the impregna-
tion pressure increased, as shown in Figure 5.12. h e i gure shows that the