Profile of wood species used in local and imported plywood and their bond performance
2015
Jimenez, J.P.Jr. | Escobin, R.P. | Conda, J.M.
The wood species currently used in local plywood production, as well as the dominant species used in imported plywood, was determined. The bond performance of both local and imported plywood was also assessed using PNS 196:2000 and ISO 12466-2:2007 standards. With a 20x hand lens and a Leica digital stereoscope, identification was done by examining the physic-mechanical and macro-anatomical properties of the samples and comparing them with wood samples lodged at the FPRDI wood library. Results showed that the majority of the local companies especially those from Mindanao [Philippines] used Falcataria moluccana as the dominant species for plywood production. Depending on veneer quality, this species was used as outerply, core, cross bands and lumber core. Shorea sp., Artocarpus blancoi, Weinmannia sp., Heritiera sp., Pinus sp., and Endospermum peltatum were not only used for outer plies, but also as core and cross bands depending on veneer quality. On the other hand, imported plywood used only Populus sp. a cross band and core. Helicia sp. and an unidentified species (too thin for identification) from the family Anacardiaceae or Burseracease were usually used as outer plies. The bond test revealed that local plywood conformed to both PNS and ISO standards for Type 1 exterior plywood regardless of the species used in the layers as long as the adhesives used was phenol formaldehyde. In contrast, though imported plywood used only Populus sp. in the cross band and core, it did not conform to both standards due to the use of melamine glue, a weaker exterior adhesive than phenol formaldehyde.
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