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1) PhD student, Center for Wood Sciences, University Hamburg
goran.schmidt@uni-hamburg.de
2) Project leader, Dr., Fraunhofer WKI Institute for Wood Research
dirk.berthold@wki.fraunhofer.de
3) Wood scientist, Fraunhofer WKI Institute for Wood Research
mathias.belda@wki.fraunhofer.de
www.holz.uni-hamburg.de
www.wki.fraunhofer.de
Establishment of the bamboo panel industry
sector in East Africa
Development of a scrimber panel based on Ethiopian highland bamboo
Goran Schmidt1), Dirk Berthold2), Mathias Belda3)
Set up a cooperation network
Ethiopia is one of the rising economies in Sub-Saharan
Africa with a large gap between available raw
materials and strong industrial growth.
Ethiopia owns ca. 1 million ha bamboo lands (2/3 Africa)
Lack of process knowledge and industrial involvement
limited the bamboo sector to low-value products
The strategic alliance framework “Development of the
industrial bamboo sector in Ethiopia” funded by GIZ
Incubator company, African Bamboo established a pilot
plant in Addis Abeba in 2013
Combined expertise of glue suppliers (Dynea, Solenis,
BASF), machinery developers (Dieffenbacher, Raute,
BigonDry) and research (WKI)
Bamboo scrimber panel in brief
Common bamboo scrimber are highly densified board
materials with densities >1.2 g/cm³ for high wear areas.
Chinese producers refer to it as woven strand board
Decentral supply chain involving about 2.000 bamboo
farmers and microenterprises
Culms are split and roller-crushed to strand mats
Strand mats are kiln-dried and “carbonized” in hot air
or saturated steam chambers
Glue applied by dipping bundles into tanks, controlling
glue concentration (>20 %) by soaking and drip-off time
Hot-pressing with >15 N/mm² and cooling down
Goals to achieve
We aimed to develop a lighter and more resource
efficient scrimber bamboo panel based on the African
highland bamboo Yushania alpina.
Analyse raw material properties and fluctuations
Adopt Asian WSB process to existing machinery
Find appropriate glue and application method
Identify process steps for enhancing product quality
Conduct testing programme for market entrance
The most promising variant was selected for further
investigation in commercial scale.
Spraying application of 10 % PF-System 2 (50/50)
Mix of 2 % Pro A18 Sasol wax
Heat treatment was not necessary to fulfill thresholds
Resistance against biodeterioration remains unclear
Market entrance facilitation
A test programme according to European quality
requirements shall help market entrance.
Commercial scale panels were produced and undergo
comprehensive standard testing
Absence of full standard for outdoor products made
from alternative lignocellulosic raw materials
First oriented to WPC standard EN 15534
Recently drafted EN 17009 will regulate requirements
Ongoing investigations
Does raw material assorting enhance product quality?
The fibre content increases with culm height
Density profiles and physical properties will be
analyzed for panels made from three different raw
material groups (top, middle, bottom)
Does thermal treatment effect biological performance?
The influence of thermal treatment on the resistance
against different biodegrading agents (soft rot, brown
rot, white rot, termites) is currently investigated
Overcome raw material challenge
Bamboo contains high amounts of silica, waxes, water
and sugars.
Silica 0,1 to 1,6 [m%] was found in extracellular spaces
Only negligible wax was found in the epidermal layer
Significant moisture fluctuations (86 < MC < 130 [%])
Metabolic sugars fluctuate less in mature culms
Starch changes amounts to 4,68 in dry and 3,05 m% in
the rainy season
Investigate production parameters
A screening test of a production parameters was
conducted for lab-scale panels.
Untreated vs. treated (160, 180, 200, 220 [°C]; 3, 5 [h])
Three different types of glue (four PF-based, one
acrylate and one soy-based)
Different glue applications (spray, powder, curtain)
With or without hydrophobic agents
The results were compared to LVL and OSB3 references
threshold values.
Thickness swelling threshold TS < 6 %
Internal bond threshold IB > 0,5 N/mm²
Flexural strength threshold MOR > 90 N/mm²
Flexural strength threshold MOE > 16 kN/mm²
1) Loading a combined kiln-drying and thermal treatment chamber with a stack of strand
mats 2) Spray application of PF resin with industrial scale equipment 3) Mat formation
showing narrow strands in the core and broad strands in the face layers
1) Average content of sugars in 4 yr. old culms of the dry and rainy season based on culm
dry mass, 2) Manual culm harvest in the dry season in Ethiopia‘s South
2 3 1
1 2
Promising test results for spray application and identification of „best variants“
1. Plantation 2. Culm harvest 3. Post-harvest 4. Mechanical
processing
8. Condition, Sand,
Finish 7. Hot press 6. Glue application 5. Thermal
treatment
Simplified process flow scheme showing the main technological challenges
1
1) Fungal mycel appears in voids in between compressed fibres 2) Phenolic glue did not
hinder basidiomycetes 3) Intact parenchyma attracts fungal attack (Coniophora puteana)
2 3
1) Planks cut from final product produced at WKI 2) Top view of untreated panel
1 2
0
250
500
750
1000
1250
04812 16 20
Density kg/m³
Panel thickness [mm]
Density Average sample density
Density profile of a scrimber panel using untreated and unsorted bamboo strands
Pre-
Treatment
Glue type
TS (%)
0 % Wax
TS (%)
2 % Wax
IB (N/mm²) MOR
(N/mm²)
MOE
(N/mm²)
160°C / 3h PF-System 1 9,8 4,1 0,6 109,3 24400,2
160°C / 3h PF-System 2 4,3 2,8 0,3 87,2 18361,0
160°C / 5h PF-System 1 4,6 4,9 1,0 171,7 26048,8
160°C / 5h PF-System 2 2,1 1,8 1,3 136,0 21906,1
180°C / 3h PF-System 1 3,2 3,1 1,0 146,5 23595,3
180°C / 3h PF-System 2 6,4 2,6 0,2 119,7 26571,0
180°C / 5h PF-System 1 2,8 3,4 0,6 104,7 23098,7
180°C / 5h PF-System 2 2,0 1,3 0,7 130,6 24322,6
200°C / 3h PF-System 1 6,0 2,4 0,4 87,3 26245,7
200°C / 3h PF-System 2 3,6 3,0 0,8 115,0 26464,6
200°C / 5h PF-System 1 2,9 1,8 0,6 97,3 22052,2
200°C / 5h PF-System 2 4,3 1,9 1,0 131,0 25580,2
220°C / 3h PF-System 1 3,2 0,5 72,0 21807,8
220°C / 3h PF-System 2 3,2 0,4 73,4 21453,6
Untreated PF-System 1 1,8 2,3 0,8 126,1 19282,0
Untreated PF-System 2 5,8 3,1 1,0 195,5 26490,4