Civil Engineering Reference
In-Depth Information
1.25 g/mL at 25°C, 12-15 wt%; the form of polymer was powder and was used in pow-
dered form as well.
13.2.2
Whisker Isolation
h e whiskers were isolated from kenaf bast i bers following the method of Siquera
el
al.
[10]. Kenaf bast was ground to 0.25 mm size by FRITSCH universal cutting mill
pulverisette and treated with 4% (w/w) NaOH solution at 80°C for 2 hours. h is treat-
ment was repeated 3 times. At er each treatment, i bers were i ltered and washed with
distilled water until the alkali was completely removed. A subsequent bleaching treat-
ment of the i bers using the same amount of acetate buf er, aqueous chlorite (1.7%
w/w), and distilled water was applied in order to bleach the i bers. h e bleaching treat-
ment was carried out four times at 80°C under mechanical stirring. Acid hydrolysis
was performed by subjecting 4-6% (w/w) bleached kenaf bast pulp into preheated 65%
(v/v) sulfuric acid at a temperature of 50°C for 60 min. h e suspension was constantly
mixed using a magnetic stirrer. h en, the hydrolyzed pulp was centrifuged at 4,000 rpm
for 30 min and dialyzed in distillated water. Subsequently, the whiskers suspension was
homogenized by using an Ultra Turax T25 homogenizer for 5 min. Some drops of chlo-
roform were added as protectant to the whiskers suspension which was stored at 4°C.
13.2.3
Nanocomposite Preparation
h e composite materials were prepared by solution casting. A mixture of dif erent
weight percentages of whiskers and CAB in acetone (15 wt% CAB in acetone) was pre-
pared by stirring on a hot magnetic plate at 50°C for 3 hours until a homogenous mix-
ture was obtained. Dif erent whiskers percentages were used as reinforcement in the
CAB matrix. h e percentages of reinforcement used in this study were 2.5, 5, 7.5, and
10%. At er the well-mixed solution was achieved, the prepared formulations were soni-
i ed for 5 min. h e solutions were cast on well-dried glass petri dishes. h e glass petri
dishes were wet with lubricant in order to prevent composite sticking to the glass. h e
formulations were placed in a vacuum oven at 45°C for 48 hours to evaporate the sol-
vent. h e nanocomposites produced were kept at room temperature for 5 days before
preparation of the specimens. h e thickness of i lms was around 0.5 mm with a total
dry weight of about 5 g. Formulations can be seen in Table 13.1.
Table 13.1
Formulation of prepared materials during processing.
No
Composition
CAB
Whiskers
1.
CAB (100)
100
2.
CAB-whiskers (97.5/2.5)
97.5
2.5
3.
CAB-whiskers (95/5)
95
5
4.
CAB-whiskers (92.5/7.5)
92.5
7.5
5.
CAB- whiskers (90/10)
90
10
