Daisy A Sriwendari, Edwin K Sijabat / JBAT 9 (2) (2020) 126-134
Table 1. Raw Material Characteristics.
No.
Parameter
BNC
(OCC) Short Fiber
(OCC) Long Fiber
1.
Fiber Length
26-45 nm
1,006 mm 161 ml CSF (Unbeaten)
1,209 mm
0 ml CSF (Revolution 1000)
318 ml CSF (Revolution 1000)
2.
Freeness
3. 4. 5. 6.
Initial pH
3.90 7.49
7.71
7.87
pH washed with NaOH Particle Charge Detector
-
-
-157 mV
-185 mV
-173 mV
Charge Demand
0.569 μ eq/L
0.421 μ eq/L
0.431 μ eq/L
Solenis. While the equipments used include beater (PTI), disintegrator (PTI), beaker glass, analytic balance (PTI), vacuum (PTI), filter paper, hot plate (L&W/3-3), dispermat (PTI), handsheet maker (PTI), blotting paper, speed dryer (PTI), turbidity meter (PTI), Canadian Standard freeness (CSF) tester accroding to TAPPI, pH meter, ring crush tester (L&W/5-2), concora tester (Buchel BV/75- 08-01-0002), cobb tester (Workshop/100CMQ), densometer (PTI), internal bonding test (Huygen/1314).
RESULTS AND DISCUSSION
The results from the nata de banana and secondary fiber characteristics test are described in Table 1. Based on table.1, the results from raw materials tests indicate that BNC has the same negative charge as the charge of wood fiber in general. But it has an acidic pH, so it must be washed first with a 1% of natrium hydroxide (NaOH) solution.
Methods
Freeness Test Results
The 110 gsm hand sheet test liner was made by preparing the ingredients first, the beating nata de banana and secondary fiber process were done separately. Then the freeness, charge, pH, and consistency checks were conducted. The hand sheet blank was made by using 100% old corrugated containers with additional cationic starch, Poly Aluminum Chloride (PAC), AKD and cationic retention, and coating the surface sizing with the surface sizing agent. Whereas the trial hand sheet was made by using variations in the composition of raw materials of old corrugated containers and BNC based on predetermined compositions of 0%, 5%, 10%, 15%, 20%, 25%, and 30% with the addition of cationic starch and AKD only, and coating the surface sizing using BNC as a substitute for the surface sizing agent. Several wet end stock properties (drainage, turbidity, pH) were then tested along with the tests on several paper properties (ring crush index, concora index, bursting index, ply bonding, porosity, and cobb size). Then an analysis was conducted to compare the test results between blank sample and the trial sample.
Before being used as raw material for the handsheet, the raw material was beaten by using hollander beater, the OCC long fiber has 318 ml CSF freeness after 1000 rpm beating, the secondary fiber of OCC short fiber has 161 ml CSF freeness unbeaten, and BNC has a 0 ml freeness CSF after 1000 rpm revolution. The BNC must be able to be homogeneously mixed with raw materials or other additive materials before it can be added on the surface sizing. Therefore it must be beaten with a hollander beater at a 7000 rpm revolution. Then the freeness value is checked, which is at 0 ml CSF. According to Sijabat et al. (2017), the absence of water coming out in the BNC freeness test is because the structure of the BNC itself is in the form of gel and very small in size, with a diameter of about 2-20 nm and length of 100 - 40,000 nm. The non-branched glucose chain makes a long fibrillar structure, because of the high number of free hydroxyl groups that produce extensive intra and intermolecular hydrogen bonds between adjacent chains (Brown, 1985). These fibres are very small and made of nano-sized fibers thus making the braid really strong and tight that even water will struggle to penetrate it. Therefore, in freeness testing, water cannot get out of the CSF tester mesh.
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