Global Journal of Science Frontier Research, G: Bio-Tech & Genetics, Volume 22 Issue 2

glue spread of 140 g/m 2 with plywood pressed by high temperature (120 and 150°C) by phenol formaldehyde condensation. The results showed that lower temperature pressing was significant without worsening of mechanical properties of plywood. Moisture content of veneer was 10-12%, 2 mm thick, it used cornstarch- tannin-phenol formaldehyde amount 225 g/m 2 , at 125°C in 6 min, loading presser was 12 bars as the result of MOR was 41 N/mm 2 of the control, 70 N/mm 2 of the cornstarch PF, MOE was 2,958 N/mm 2 of the control, 4,271 N/mm 2 of the cornstarch PF, strength tension in 8 hours boiling water was 0.5 N/mm 2 of the control, 1.75 N/mm 2 of the cornstarch PF, wood failure was 11% of the control, 72% of the cornstarch PF and formaldehyde emission was 2.62 mg/m 2 /h of the control, 1.92 mg/m 2 /h (Moubarik et al. , 2009). Lignin phenol formaldehyde resolves were prepared different of lignin at both 20 and 40% phenol replacement (Ghorbani et al. , 2016). Phenol formaldehyde was low formaldehydes effectives with products and user, high water resistance, it was developed for outdoor plywood and PF was used improve teak plywood in Laos and supporting information to Lao industry. Thermo wood modification method has been found since early part of the 20 th century (Callum, 2011). Wood modification could be the best option for improving teak plantation in Laos. For instance, thermo- plywood can increase durability and dimensional properties of the product and it can also reduce chemical use for wood preservation. For example, worldwide is concerning environmental effect, especially, European zone is high restricted use of toxic preservation and the market for new durable products of modified wood during the last few years(Sandberg et al. , 2017). Even though thermal modification is long-known method, considerable amount of research has recently focused on this method and heat-modified wood has an important market share (Kantay & KARTAL, 2007). Thermo-wood modification can be performed in special thermal treatment kilns as well as under pressure and heat using special press equipment. Considering special thermal treatment kilns, five processes have been developed and are currently available at industrial scale. Thermo-plywood products can extend young teak duration, safe for users and environmentally friendly because thermo-veneer to be able chemical composition of teak veneer, thermo-plywood never use chemical elements (toxic) which only using glue ability and the product high resistances with insect destroying such termites, beetles, and others. Generally, Teak log thinned from plantation is less utilization in Laos, which has small diameter and more proportion of sapwood. Famers have been using it for fence, poles, firewood, discard on the ground plantation site and some burning. Young lumber teak is low insect resistance especially termites, fungus, and beetles. The modern alternative to improve wood products needs to be modernized wood technology into wood industrial in Laos. Thermo-plywood method is believed to be able to increase smart teak products without chemical and high insect resistance through removing chemical composition of the wood, thermo- wood is thermal modification. According to Mohamed et al. (2018) found that thermo wood, whenincreasing temperature in the range of 160-220 °C. Thermo-Wood® method for about 1 and 2 hours at temperatures of 190 and 212 °C in an industrial business (Aytin et al. , 2015). Both research article confirms that thermal domification to be change chemical composition of the wood by temperature increasing rang in the range more 160°C. This study objectives to investigated physical and mechanical properties of thermal plywood of PF adhesive. Physical property focused on density, water absorption and swelling. And mechanical property was MOR, MOE, shearing strength and hardness. II. M aterial Teak veneer was peeled insplindleless rotary at the Faculty of Forest Science, National University of Laos, Vientiane Capital, Lao .P.DR. A small wood hot pressure machiner (model STK No. 44-275, DAKE, Grand Haven, MI, USA), A Cole pressure machiner (model No BY 814*4/2B, Production code 7265, Made in China), a hot pressure machiner (model, No BY 214*4/2A-1, Production code 7276 Mad in China), a circular saw cutter (model, No BJ 6116-4B, Production code 180401), dial thickness gaugedigital calipers (code 34-506, Measumax, Melbourne, Australia) were used. And Horizontal Flow Oven (Model WOF-050, serial No WOF050071018002, Made by Daihan Scientific Co., Ltd). III. M ethodology The veneer was cut into pieces measuring 2 mm x 400 mm x 400 mm with a total of 60 pieces of peeled veneer; the moisture content of veneer ranged from 6 to 12% based on air-dry weight. The thermal treatment processes were based on the factorial design as 5 x 13 x 30 = 1,950 (four different temperatures, i.e. , 180, 200, 220, and 240 °C; three different times, i.e. , 4, 8, and 12 min for the treatment of five peeling veneer at a time). The adhesive to apply on teak veneer for teak plywood products is phenol formaldehyde based on Standard (2012). Plywood product consists of 5 layers or 10 mm of thickness, veneer laying should be placed over to another with perpendicular grain. PF glue should be speeded on the veneer by passing them through the roller of a glue transfer spreader between 150 g/m 2 . Dimension of teak plywood product is 40x40 cm which it is hot press machinery. The hot press rate used as 1mm thick per 1 min, thermo-teak plywood and teak © 2022 Global Journals 1 Year 2022 78 Global Journal of Science Frontier Research Volume XXII Issue ersion I VII ( G ) Physical and Mechanical Properties of Teak (Tectona Grandis L.Fil.) Thermo-Plywood from Plantations in Lao P.D.R