Impregnation of Bamboo (Gigantochloa Scortechinii) with Phenolic Resin for the Production of Dimensionally Stable Plybamboo
Low molecular weight phenol formaldehyde (LMwPF) resin was used to enhance the dimensional stability of bamboo strips (Gigantochloa scortechinii). Resin was impregnated into bamboo strips via vacuum process before the strips were converted into plybamboo. The present study was undertaken to devel...
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| Format: | Thesis |
| Language: | English |
| Published: |
2008
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| Online Access: | http://psasir.upm.edu.my/id/eprint/5104/1/FH_2008_8.pdf http://psasir.upm.edu.my/id/eprint/5104/ |
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| Summary: | Low molecular weight phenol formaldehyde (LMwPF) resin was used to
enhance the dimensional stability of bamboo strips (Gigantochloa scortechinii).
Resin was impregnated into bamboo strips via vacuum process before the strips
were converted into plybamboo. The present study was undertaken to develop
a process to produce high dimensionally stable plybamboo. The work included
evaluation of resin impregnation process, establishment of suitable
drying/curing technique and final pressing of phenolic-treated bamboo strips.
Evaluation of bonding properties, dimensional stability and mechanical
properties of phenolic-treated plybamboo were also conducted. The bamboo
strips were taken from basal and middle portions of bamboo culm. To treat the
bamboo strips with LMwPF resin, firstly, a vacuum period of 1 hour was applied before the strips were soaked in resin for at least 90 minutes. The
samples were later dried in an oven at 60°C for 9 hours. The mean weight
percent gain (WPG) and moisture content (MC) of dried phenolic-treated
bamboo strips were 14.5% and 7%, respectively. Drying the phenolic-treated
bamboo strips for > 9 hours resulted in cupping of the strips.
Phenolic-treated strips were then hot pressed for 5, 8, 11, 14 and 17 minutes at
14 kgm-2 and 140°C. Water absorption (WA), thickness swelling (TS) and linear
expansion (LE) of the strips decreased when the curing time was extended from
5 minutes to 17 minutes but antishrink efficiency (ASE) increased. The mean
value of modulus of rupture (MOR) for untreated strips (177 Nmm-2) was
significantly lower than the phenolic-treated strips (224 Nmm-2) after 17
minutes pressing time. However, no significant difference was observed in
modulus of elasticity (MOE) and compression parallel to grain. Results showed
that the optimum pressing time for phenolic-treated strips was 11 minutes.
This work also established an optimum pressing time to produce high
dimensionally stable plybamboo. For this, phenolic-treated bamboo strips were
glued together edge-to-edge using phenol resorcinol formaldehyde (PRF) resin
to produce a veneer. The veneers were then assembled perpendicular to each
other to form a 3-ply (12 mm) and 5-ply (20 mm) plybamboo using phenol
formaldehyde resin as a binder. The plybamboos were hot pressed at an optimum pressing condition of 140oC (pressure 14 kgm-2) for 22 (3-ply) and 33
(5-ply) minutes. The bonding strength of the plybamboo obtained in this study
met the minimum requirement of MS 228-1991. WA, TS, and LE of phenolictreated
plybamboo were significantly lower compared to those of untreated
plybamboo.
The MOR, MOE and compression parallel to grain of the phenolic-treated
plybamboo were significantly higher compared to those of untreated
plybamboo. For 3-ply, the values were 164 and 127 Nmm-2 for MOR, and 19767
and 16778 Nmm-2 for MOE, and 60 and 41 Nmm-2 for compression parallel to
grain, respectively. Similarly, for 5-ply phenolic-treated plybamboo the MOR,
MOE and compression parallel to grain of were 38%, 30% and 33% respectively
higher than those of untreated plybamboo. Generally, the treatment of bamboo
strips with LMwPF resins were found to significantly improve the properties of
plybamboo made from them. |
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