36
© 2013 Published by Center for Pulp and Paper through REPTech2012
Chloroform CHCl
3
and urea were purchased from R M Chemicals, meanwhile sodium hydroxide
NaOH, sodium chlorite NaClO
2
and 2-naphthol were acquired from Friendamann Schmidt Chemicals
and Sigma-Aldrich, respectively. Choline chloride and standard cellulose were bought from Acros Organics
. Other chemicals were purchased from Systerm. All
chemicals were used as received.
2.2. Dewaxing Process
Kapok iber 8.0 g was added to CHCl
3
800 mL. The mixture was reluxed for 4 h. Then, the mixture
was iltered, washed with methanol and dried. The dewaxed iber was kept in tight container prior to use.
2.3. 2 Naphthol Pre-Treatment
Dewaxed kapok iber 8.0 g was immersed in acetone 800 mL containing 2-naphthol 3.2 g. The
mixture was stirred for 12 h at room temperature. After thorough mixing, the iber was air-blown to dryness at
room temperature. The pre-treated iber was kept in tight container prior to use.
2.4. Conventional Method
Dewaxed kapok 4.0 g was added to 400 mL distilled water and heated for 2 h at 70-80
o
C. For deligniication process, dried CHCl
3
treated iber 3.0 g was added to NaClO
2
5.0 g in water 240 mL, followed by acetic acid 2.0 mL. The mixture
was heated for 3 h at 70
o
C. After that, the iber was iltered, washed extensively with distilled water and
methanol. The process was repeated three times. Then, NaClO
2
treated were dried at 40
o
C in a vacuum until a constant weight was achieved. Dried NaClO
2
3.0 g treated iber was then added to NaOH 4 , 300 mL. The mixture was heated for 4 h at 85
o
C. The obtained cellulose was later washed comprehensively
with aqueous acetic acid and distilled water. Then, the iber was dried in vacuum oven at 40
o
C until a constant weight obtained.
2.5. Dissolution in DES Method
Choline chloride 96.8 g and urea 60.1 g were heated until homogenous colorless liquid formed. Then,
dried 2-naphthol treated iber 3.0 g was added to the prepared DES, followed by the addition of NaOH
3.72 g. The mixture was stirred for 20 h at 90
o
C. The clear liquor obtained containing cellulose-rich extract
was poured to adequate distilled water as non-solvent to precipitate cellulose suficiently. The isolated crude
cellulose was added to 2.0 H
2
O
2
- 0.2 cyanamide solution 180 mL and stirred at 50
o
C under pH 10 for 4 h. The bleached cellulose obtained was iltered and
washed with water and ethanol. Finally, it was dried in an vacuum oven at 40
o
C until a constant weight obtained.
2.6. Organosolv Treatment Method
