1. COMPARATIVE PROPERTIES OF AGROFIBER BASED PARTICLEBOARDS USING NEWLY DEVELOPED BONDING MATERIALS
Zeinab A. Osman, Ph.D
Department of Cellulose Chemistry and Technology
Institute for Technological Research
National Center for Research
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2. Contents Brief introduction Objectives of the study
Experimental, adhesives formulation and Particleboard preparation.
Preparation of cost effective adhesives, labs and semi industrial trials
Results
Conclusion
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3. Introduction 1- To save forests. Surface area 2,558km
2- To provide wood alternatives (renewable resources) to
replace the traditional solid wood.
3- to meet the demand on wood products.
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4. Objectives The objectives of this work are:
To provide technical information on the manufacture of agro fiber particleboard and to develop new bonding materials of high performance and of low cost to compensate for the lighter weight of these fibers which necessitate the use of high level of resin loadings.
It also aimed at evolving the optimum conditions and process technology for the utilization of these fibers without any further treatment (chemical, mechanical) in order to reduce the overall cost of production.
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5. Experimental Adhesives formulations
Solutions of the Pine tannins with two different concentrations (35% and 47%) and two different pH values (5 and 9 respectively) were used in mixtures with different hardeners such as:
1. Tannins modified – 8% paraformaldehyde.
2. Tannins – 5% paraformaldehyde.
3. Tannins – 5% urea and 5 % paraformaldehyde.
The PUF resins were obtained from Dynea Company, Austria and phenol formaldehyde.PF which was synthesized in laboratory according to the procedures outlined in the Advanced Wood Adhesives Technology (Pizzi, 1994) and a commercial PMDl were used to formulate different adhesive systems.
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6. Particleboard preparation
One layer laboratory particleboards of 350 X 310 X 16 mm dimensions were produced from different fibers by using previously mentioned formulations.
Different levels of resins loadings and different board densities comprised between 550 and 670kg/m3 were used. A pressing cycle with an initial maximum pressure of 61 bars and a pressing time of 5.30 to 7.30 minutes was used.
Agricultural wastes and low quality fiber :
- The Bagasse
- The hemp
Eucalyptus
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7. Manufacure of particleboard : Results and Discussion
Panel from the Bagasse
Glue formulations
Internal bond
(MPa)
V100
Thickness swelling
(%)
Density
(Kg/m3)
18% pine tannin
8% paraformaldehyde
0.34
0.11 34
699
11% pine tannin + 3%PMDI
5% paraformaldehyde
0.23
0.00 50
639
11%PUF+3%PMDI + 1% pine tannin+ 0.1paraformaldehyde
0.24 40
629
PUF (15%)
0.31
0.12 26
638
13%PUF+ 2%PMDI
(15%)
0.21 36
PUF
0.46
0.14 54
842 pH
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8. 4/6/2019

9. Manufacure of particleboard : Results and Discussion
Panels from Eucalyptus
Glue formulation
Ref = 0.35
Internal bond
(MPa)
V100
Thickness swelling
(%)
Density
(Kg/m3)
PMDI
(8%)
1.04
0.19 31
596
14 pine tannin+8% paraformaldehyde
0.75
0.11 45
663
14 pine tannin+ 5% paraformaldehyde +5% urea
0.27
0.00
672
10% pine tannin+3% PMDI+5% paraformaldehyde
0.78
0.15 40
614
7%PF +3% PMDI+1% pine tannin
0.1 paraformaldehyde
0.44
0.12 44
610
PF + 10% pine tannin
0.25
7%PUF +3% PMDI+ 1% pine tannin
0.47 53
608
PUF alone
(15%)
0.10 37
810 pH pH
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10. Conclusion
- The Eucalyptus and the bagasse having both a lower pH produced inferior quality panels which did break during the tests. This only applied when resins of lower pH were used or when an acid or neural material such as the urea, polymeric diphenylmethane diisocyanate (PMDI) was mixed with the tannins, PF and the PUF.
- Satisfactory performance of tannin-based adhesives with the Hemp, the Bagasse and  the Eucalyptus at relatively high pH.
- Panels from Hemp (without depithing), can be used for furniture (EN 312 – 3)
- When we increase the density of panel made from Bagasse we obtain panel suitable for furniture and internal uses
- The light weight of agricultural wastes is the necessity of utilizing high percentage of the adhesives.
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11. Formulation of Low- cost adhesives
Why ? :
1 – Light weight of agricultural wastes
Bagasse
2 – Interest of the European industry, Dynea Company
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12. Formulation of Low- cost adhesives : Materials and methods
Formulations
Commercial PUF resin with 46 30 25 20 15 8
+ Low percent of PMDI (10, 8, 5%)
(expensive )
% of Urea
cheap
Addition of urea (heating) (50°C for t 30 min).
Evaluation of the particleboard
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13. Formulation of Low- cost adhesives
Values of V100
Thickness swelling
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14. Semi Industrial trials
Formulations has been chosen for their excellence and cost effective:
PUF + 15 % of urea
PUF + 20% of urea
reference value for V100 = 0.15
Glue formulations
V20
(MPa)
V100
Thickness swelling
(%)
Density(kg/m3)
PUF
0.22
0.10 16
646
+ 10% PMDI
0.73
0.25
727
+ 15% urea
+ 10%PMDI
0.57
0.19 18
714
+ 20% urea
0.52
0.16 17
707
Glue percent = 13.5%
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15. Evaluation of the particleboard from agricultural wastes and cost effective adhesives
Low-cost glue from PUF + 15% urea + 5% PMDI (15%)
Types of agric. wastes
Internal bond
(MPa)
V100
Thickness swelling
(%)
Density
Pressing time
(Min.)
Cotton stalks
0.41
0.14 34
713
5.30
Bagasse
0.34
0.13 21
708
7.30
Groundnut shells
0.00
710
Maize straws
0.10
717
Internal bond value > standard value(0.24MPa)
For panel for general utilisation
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16. General Conclusion
1 - Cost effective formulations have been invented from PUF and PMDI and it can be used for the production of panels with exterior qualities. The lab experience has been transferred to the industry with great successful.
2 - the possibility of using agricultural wastes in the panels manufacture has been proven, the process still to be optimized.
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17. Acknowledgements
National Center of Research and the French embassy sponsorship of this research are very acknowledged.
Dynea company, Austria for the provision of the PUF
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18. Thanks for your attention
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