Effect of cold setting adhesives and glue spread on properties of oil palm trunk laminated veneers
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Date
2009
Authors
Sarmin, Siti Noorbaini
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Abstract
Researches on Laminated Veneer (LV) manufactured from oil palm trunk
(OPT) veneers are being developed in line to reduce waste from oil palm
biomass. However, there was little information available concerning the
effects of adhesives types on tensile shear strength, bonding, shrinkage and
swelling of these laminated products from oil palm. The objective of this study
was to investigate some of the properties of LV made from OPT using cold
setting adhesives namely Emulsion polymer isocyanate - copolymer Vinyl
acetate (EPI-VAc), Emulsion polymer isocyanate - copolymer Styrene
butadiene rubber (EPI-SBR) and Polyvinyl acetate (PVAc). Three layers of
LV were produced based on the lab scale size (23 cm width by 23 cm length
by 4.5 mm of each veneer) using two different adhesives spread level; 250
g/m2 and 500 g/m2 on single bonding surface of the veneers (single glue
line). Adhesives were spread uniformly on the veneers manually. The panels
were pressed at 1MPa for different duration. Oil palm trunk LV bonded with
EPI-VAc and EPI-SBR was pressed for 30 minutes at a temperature of 30oC.
Oil palm trunk LV bonded PVAc were pressed for 60 minutes at 30oC. Ten
replicates were used for each adhesives type. Laminated veneer made from
rubberwood was used as a control samples. The anatomy and properties of
OPT were also evaluated. The wettability of veneer by an adhesive was
measured by the contact angle. From the study, the liquid viscosity and the
roughness of the surfaces affected the final measurements of contact angle
droplets. The results showed that there was significant interaction between
adhesives and properties of the LV panels. Values of shear strength for OPT
LV panels were comparable with rubberwood LV especially those produced
using PVAc adhesive. The OPT LV bonded with EPI-SBR was showed the
lowest percentage of thickness swelling and water absorption as compared
to OPT LV bonded with EPI-VAc and PVAc adhesive respectively. The
physical and mechanical properties were decreased after exposed to cold,
hot and cyclic treatment. From the observation on absorption and desorption
properties in different relative humidity condition, OPT LV manufacture with
EPI-VAc perform the highest fibre saturation point and the least was
experienced by OPT LV bonded using PVAc. The OPT and rubberwood LV
panels were detected to have a dimensional change as the relative humidity
was shifted. The soil burial study showed OPT LV was easily proned to
biodeterioration attack. The OPT LV and rubberwood LV produced with EPISBR
were exhibited the highest percentage of weight loss as compared to
OPT LV and rubberwood LV bonded with EPI-VAc and PVAc. From the
observation on using different spread level, panels bonded using 500 g/m2 of
spread level was showed better performances through the physical and
mechanical properties for both as compared to 250 g/m2 spread level; OPT
and rubberwood LV respectively. As compared to BS 6566: Part 8 (1985)
standard, the OPT LV bonded with those adhesives was comparable and
acceptable.
Description
Master
Keywords
Chemical science , Adhesives , Oil palm trunk