POTENTIAL OF () AS A SOURCE OF RAW MATERIAL FOR PULP AND PAPER IN GHANA

Daniel Sekyere

Forestry Research Institut.of Ghana UST P. O. Box 63, Rumasi, Ghana

ABSTRACT - 'Laboratory studies were carried out to determine the pulping characteristics of a local variety of Bambusa vulgaris. The fibre length of 2.65mm and Runkel Ratio of 1.03 suggest that bamboo fibres might be suitable for pulp and paper-making. The bamboo with a lignin content of 26.8% and cellulose of 61.2% was cooked with 18% active alkali for 90mins to obtain a yield of 54.2% and kappa number of 48~2%. The pulp evaluations showed that it is not necessary to separate the node from the internode during pulping. The physical and strength properties of the pulp produced also showed that the bamboo can make good papers.

Keywords - Bambusa vulgaris, alkali pulping, fibre dimensions, chemical composition INTRODUCTION

Bamboo belongs to the family of sulfite process is considered to be graminaceae. In Ghana, the most unsuitable (Ukil, 1961). Bamboo, common species is the Bambusa however, is readily pulped by the vulgaris (Irvine, 1961). The sulphate process to a bleachable structure of bamboo differs from pulp. wood, having solid nodes and hollow internodes at regular intervals. Because development and The solid node has a high density growth characteristics are affected and a high silica content which by enviromental factors, it is causes considerable difficulties important to study the characteris~ and expenses in chipping. Despite tics of in Ghana to this, bamboo has been used ascertain their suitability for successfully for various paper papermaking. grades (FAO, 1973). This paper presents the results of Suitability of bamboo species with pulping of bamboo from pakyi in the different pulping processes for Ashanti Region of Ghana. various grades of paper has been evaluated in different parts of the world. (Guha, 1961; Guha et al, MATERIALS AND METHODS 1975). Fibrous raw material preparation In many respects bamboo offers advantages over wood as a raw The internode was separated from material for paper making. It.grows the solid node and were cut rapidly and is ready for use within separately by hand to chip size of a few years and also coppices about 8 x 10 x 30mm by hand. easily. It is estimated that 6"';'7 The nodes and internodes were times as much cellulosic maeerial weighed; moisture contents were can be obtained per hectare from a determined, and the respective bamboo forest as can be obtained percentage oven-dry weights were from a coniferous or other broad calculated. leaved forest (Lessard and Chouinard 1980). It is reported Fibre Dimension that bamboo plantations will be ready for harvesting from the tenth Portions of the internode (90%) and year, and that the annual yield node (10%) were treated with equal will then be three tons green volumes of glacial acetic acid and weight per hectare (FAO, 1973). hydrogen peroxide (20% volume) in a For pulping of bamboo, the acid beaker. The beaker was suspended in

Gh_ Journal of Forestry Vol.1 1994 49 water at 60°C for 48 hours. The separately. fibre dimensions were measured with a microscope equipped with a Pulp Evaluat.ion micrometer eye piece. Beating was carried out in a Lampen Chemical Analysis Ball-Mill. Hand sheets were prepared according to Tappi T205 Portions of the internode and node Os-71. The sheets were tested after were milled a Willey-Mill and conditioning at 25°C and 65% s~eved through a BS 40 mesh (42um) relative humidity. The physical but retained on a BS 60 mesh characteristics of the pulp were (250um). The following analyses determined Tappi T220 Os-71. were carried out using one per cent (1%) caustic soda solubility (T40s-59) and alcohol-benzene RESULTS AND DISCUSSION solubility (T 60S - 59). Also ho10cellulose (Wise et all, and Fibre dimensions and derived values acid insoluble lignin.(T.130s - 54) for Bamboo were determined. Table 1 shows the fibre dimensions Pulping Method and derived values for Bambusa vulgaris from Ghana, Philippines The chips prepared for pulping were and India. Generally the fibres of put into a 15-1itre stainless steel bamboo are longer than those of the electrically heated ,rotating hardwoods (Tamolang et al, 1957; digester. The cooking ~onditions Tamolang, et al, 1960). Generally, adopted were the following:- the suitability of a maierial for pulp and, paper is largely determined by its,runkel ratio. The Oven-dry weight of chips(g) - 150 & 600 lower the ratio, the better the material ~or paper making (Lessard Bamboo chips to liquor ratio - 1:5 and Chouinard 1980). Ghana's bamboo, with a relatively lower Active alkali (%) - 17,18,19 & 20 runkel ratio compared to those of the Philippines and India will Sulphidily (%) - 25 therefore produce pulp of higher strength. Rise to kmre:'alui s.) 90 Chemical composition of bamboo Maximum lemperalufl' (OC) -170 The results in table 2 show that Cooking time (Mins.) - 90 the holocellulose content of bamboo from Ghana is high compared to that Cooling time (Mins.) - 15 from Philipine. Also the cellulose content of bamboo from Ghana is The sodium hydroxide and sodium higher than that of Bambusa sulphide used were analytical grade arundinacea (FAO, 1973), a species chemicals. The cooked chips were used currently for production of washed free of black liquor and pulp and paper commercially. The broken up in a disc refiner with a high cellulose content of bamboo clearance of 0.508mm. The yield of from Ghana suggests that high pulp was determined by the dilution yields of pulp could be obtained method. In this method a known from the material. There was no volume of water was added to the significant difference between the wet pulp to a specific volume. lignin contents of the bamboo from After thoroughly mixing the Ghana and that of the Philippines. suspension of this pulp and water, B. arundinacea has higher content a litre of the suspension was of lignin than,B. vulgaris from dished out, sieved and dried in air and then oven dried at 105°C. This was repeated. 5 times and the average used to calculate the yield of pulp. The Kappa Number was determined'by TAPPI STANDARD Method T236m-60. For comparative purposes, the nodes, internodes and mixture of them were pulped

Gh_ Journal of Forestry Vol.1 1994 50 Table -I: Fibre dimensions and derived values for baaboo from Ghana, Philippines and India. ** * (rom)(Jim)(Jlm)India Bambusa4.00vulgaris2.3-3-23.0017.003.50Philippine7.00137.00182.0014.6066.101,L2Barnbusa3.985.52134.00vulgaris2.0226.4215.062.770,W/12.659.651.03L/D1/0 x 100 Ghana4.95 B ambuvulgarissa LumenSlendernessFibreFibreRunkelFlexibilityFibrewidth,diameter,wallratio,length,thicknessratio,ratio, W (Jlm)

Lessard & Chouinard 1980 Varmah & Bahadur 1980

Table 2: Chemical composition of bamboo

Bambusa Bambusa" Bambusa** vulgaris vulgaris arundinaceae from Ghana from Phillippine

Holocellulose (%) 70.8 66.5

Cellulose (%) 61.2 57.6

Lignin (%) 26.8 26.9 30.1

Solubility in (%)

alcohol/benzene 2.1 4.1

1% sodium hydroxide 14.65 27.9

Data unavailable Lessard G. and Chouinard A. 1980 FAG, 1973

Ghana and Philippines. (table 2) Sulphate pulping: Influence of Comparison of the solubility in active alkali on yield and Kappa alcohol/benzene and! 1% sodium Number hydroxide for Bambusavulgaris from Ghana and Philippine show lower The yield and kappa number of pulp values for that from Ghana. is influenced by the chemical composition of the fibrous material. Table 3 shows that as the amount of active alkali increases

Ghana Journal of Forestry Vol.1 1994 51 121

...... IIlO 80 --.--.--.-.• '-'~ ...... -. -.--'

60 .--.~~. ~.:~ --.-- .. --.-•.--'--' ...•... ..--- ..--' ~ . • 40 AA - Active Alkali

111% AA 17% AA 19% AA

a\ Mixture {node &internod~)X Internode • Node o Internode • Mixture{internode & node) o Mixture A Node G> Node • Internode

2 ''0 sooo. 10000 15000 20000

Beating Revolutions'

Fig. 1 Sulphate pulping of internode, node and mixture of node and Internode of Bamboo: Pulp evaluation: Tensile index vrs Beating revolutions.

Ghana ;Journal of Forestry Vol.1 1994 52 • Node) & Internodel • InterNodeIntel'Active• NodAlkali•• ! 17% M ) c:J ...... •. e Node 12-i18% M ) \ ~ \ A .....•...... 0 "A Inter 10~ M-

...• eo • '3 ••l>4II.,,s 6 :a...•.H"K

"'"

4

o·~ 5000 10000 15000 20000 Beating Revolutions

Fig.2: Sulphate pulping of internode. node and mixture of node and internode of Bambool Pulp evaluationl Teal' index vI's. beating revolutions.

"'ana Journal of Forestry Yol.1 1994 53 lU% M 19% M 17% M

A Node X Internode •. Node 60 Internode

o Node' 60 Internode Q Node 60 Internode o Internode 4 Internode \!) Node e Node

M· Active Alkali

8J n

o

6 ------'--• - -=-."...<::...- - --4- - .------. cP

././ ,,- 4 /' ...... - Uy,-::---/~--:-::.,/ // // /.,/ iI/ / ~

o 5000 10000 ISOOO 20000

Deating Revolutions

Fig. 31 Sulp~ate pulping of internodu. node and mixture of node and internode of b:lmbuo: Pull' evaluations: Burut index vrs Dea'ting revolutions.

Ghana Journal of Forestry Vol.1 1994 54 Table 3: Sulphate pulping: Influence of active alkali on yield and Kappa Number.

Active(%) InternodeNode49.257.054.657.454.049.0 Yield % Node and Internod~__Mixture alkali as Na20 201819 17 Yield % Kappa48.243.255.536.0 No. 57.1~ 45.554.249.3

p.rcentage yield decreases. CONCLUSION Increased concentrations of sodium hydroxide not only result in high The results have shown that Bambusa rates of lignin removal but also vulgaris from Ghana with fibre accelerate the rate of attack on length of 2.65mm and runkel ratio the resistant hemicellulose and of 1.03 is suitable for paper• cellulose (Sekyere et al 1983). It making. Thus in Ghana's endeavour can be observed that when nodes, to establish a pulp and paper internodes and the mixture of the industry one of the raw materials two are cooked separately the which could be considered is bamboo differences in yield are not because it is fast growing and has 5!ignificant for the corresponding good pulping characteristics. active alkali cooks, indicating that node has no adverse effect on REFERENCES yield in bamboo pulping. For the mixture, kappa number decreases FAO (1973). Guide for planning pulp with increasing alkaline treatment. and paperenterprise.- FAO Forestry and Forest Products Studies FAO, Rome, 1973. No.18, 362pp Physical properties of the pulp Guha, S.R.D. (1961). Bamboo as a Fig. 1 shows the effect of beating raw material for paper and board revolutions on tensile strength at making. Indian Buyer 1 (2): 142. varying active alkali treatments. Tensile index increases with Guha, S.R.D.; Dhoundiyal, S.N.; & beating revolution. For these Mathur, G.M. (1975). Sulphate treatments the node tends to have pulping of giant bamboo the lowest tensile index. The 17% ( giganteus). Indian alkaline treatment of the Forester, 101 (5): 296-300. internodes gives the highest tensile index. Irvine, F.R. (1~61). Woody of Ghana, London, Oxford University Fig 2 shows the relationship Press, p.787. between beating and tear index. Tear index begins to increase at Lessard, F.G.& Chouinard, A. (1980) the onset of beating to some Properties and utilization of maximum point and thereafter Philippine erect bamboos.In Bamboo decreases. Research in Asia, Proe. of Workshop held in Singapore on 28-30th May Figure 3 shows the relationship 1980. IDRe, Singapore, p.194. between bursting index and beating revolution. Bursting strength Sekyere, D.; PIa, F. & Robert, A. increases with beating. The results (1983) Delignification of Pinus show that nodes have the lowest caribaea by oxygen and sodium burst strength while 18% alkali hydroxide. Ho1z-Forshung und Holz• treatment of node and internode Verwertung, 35:6 mixture gives the highest bursting strength.

Ghana Journal of Forestry Vol.1 1994 55 Tamolang, F.N.; Lopex, F.R.; TECHNICAL ASSOCIATION OF THE PULP Semana, J.A.; Casin, R.F. & AND PAPER INDUSTRY. (1972) TAPPI Espiloy, B.Z. (1960). Fiber Standards: Official provisional and dimensions of certain Philippine ~seful test methods. Atlanta,U.S.A. woods, bamboos agricultural crops and wastes and grasses, Part 3 Ukil, T. (1961). Bambus und Wert TAPPI, 43 (6): 527-534. fur die papierhe~s tellung Zellosteff, U. Papier 14 (10):149- 157. Tamolang, F.N. & Lopex, F.R. (1957). Fiber dimensions of certain Varmah, J .C. & Bahadur, K.N. ; Philippine broad-leaved woods and (1980). Country report and status bamboos, Part I. TAPPI 40 (8): 671• of research on bamboo in India. 676 Indian Forest Records (Botany) 6 (1) : 28

Ghana Journal of Forestry Vol.1 1994 56