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Pulping
The OPF chips 200 g, o.d.basis were pulped using acetosolv method in 4-L stationary stainless
steel digester NAC Autoclave Co. Ltd., Japan itted which a computer-controlled thermocouple.
Different acetosolv pulping conditions were run based on experimental design via the statistical modelling
software DESIGN-EXPERT. After optimization, the OPT was pulped at the best possible acetosolv
pulping conditions, which were; 85 of acetic acid, 0.75 of HCl 155
o
C of cooking temperature and 140 minutes for cooking time. Both the acetic acid and
HCl concentrations were based on volume percentage vv with respect to the cooking liquor. The resultant
OPF pulp was used as virgin pulp for this study.
Paper Making
The papermaking process was carried using semi- automatic handsheet papermaking. The mixing ratio
of OPF Acetosolv pulp to secondary pulp is listed in Table 1. Then, the handsheets were placed in air-
conditioned room 50.0 ± 2.0 RH and 23.0 ± 1.0
o
C [5].
Results and Discussions Effect of Material Mixing Ratio on Density
Fig. 1 shows effect of OPF Acetosolv pulp to ONP pulp mixing ratios on paper density. The result shows
that the sample with 100 of OPF pulp represents the lowest density of 0.5426 gcm
3
. The paper with mixing ratio of 80:20 has the highest density values. Addition
of ONP pulp after that ratio retains the paper density around 0.5700-0.5800 gcm
3
. It seems that addition on ONP pulp increases the
paper density compared to the paper density of 100 OPV Acetosolv pulp. It is believed that the short ibers
of ONP pulp illed up the open spaces between OPF Acetosolv ibers in the paper.
3.2 Effect of Mixing Ratio on Tensile Index
Fig.2 shows a comparison of the tensile index of paper produced from different ratio of pulp. Paper
with 100 ONP pulp shows the lowest tensile index compared to 100 OPF Acetosolv pulp. Tensile index
decreased with the addition of ONP pulp into OPF Acetosolv pulp
Table 1 Mixing Ratio of Pulp Sample
Ratio, OPF Acetosolv Pulp : Secondary pulp
OPF Acetosolv Pulp Secondary Pulp ONP
OD Weight g OD Weight g
1 100 : 0
24 2
80 : 20 19.2
4.8 3
60 : 40 14.4
9.6 4
40 : 60 9.6
14.8 5
20 : 80 4.8
19.2 6
0 : 80 24
Fig 1. Effect of Pulp Mixing Ratio on Density
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The virgin pulp which is believed has long iber length and more lexible contributes to the high
tensile index of the paper from 100 OPF Acetosolv pulp. While, ONP pulp that has a short and stiff iber
decreases the tensile index performance. Therefore, thepa per produced with high percentage of OPF
Acetosolv pulp will produce paper with a higher tensile index.
3.3 Effect of Mixing Ratio on Burst Index
Fig. 3 indicates that paper from 100 OPT Acetosolv pulp give highest burst index at 3.4kPa.
m
2
g. Paper from 100 ONP pulp reveals a modest index value at 3.2 kPa.m
2
g. Paperwhich contains pulp ratio of 20:80 has the lowest burst index.
Generally, it is found that the fracture toughness of the resulting paper decreased with the addition of ONP
pulp. This is due to short iber of ONP pulp cannot form a strong bonding between the ibers. In addition,
it is suspected that the presence of additives such as clay and ink in ONP pulp also lower the fracture
toughness.
3.4 Effect of Mixing Ratio on Tear Index
Fig. 4 shows that addition of ONP pulp on OPF Acetosolv pulp has signiicant impact on tearing
strength. Tear index does not exceed 7 mN.m
2
g and not lower than 5 mN.m
2
g. This value is considered as moderate values for paper. Tear index commonly
used for the purposes of newsprint is 4.70 mN.m
2
g for cross direction CD and 2.35 mN.m
2
g for machine direction MD [6]. And an increase to the addition of
ONP pulp palm fronds, where the highest content in the mixture ratio of 60 OPF: 40 ONP is 6.7 mNM
2
g after it happened declined. This condition may be due
to poor distribution of the ibers in the paper caused as light increase in the index sample of tearing OPF
ratio of 60: 40 ONP. However, this situation does not give any meaning, because as a whole observed
decrease in the index value obtained tearing. Fig. 2. Effect of Mixing Pulp Ratio on Tensile Index
Fig. 3. Effect of Pulp Mixing Ratio on Burst Index
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3.5 Effect of Mixing Ratio on Folding
