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( Joko Sulistyo ),( Sri Nugroho Marsoem ),( Tomy Listyanto ),( Nam Hum Kim ) 한국목재공학회 2018 한국목재공학회 학술발표논문집 Vol.2018 No.1
The fire-retardancy and thermal degradation of inferior tropical timber, i.e. sengon (Paraserianthes mollucana), overlaid with charcoal composite made from three wood species i.e. asam (Tamarindus indica), rambutan (Naphelium lappaceum) and melinjo (Gnetum gnemon) were studied under fire test. Borax 0%, 3% and 5% of charcoal dry weight were added into charcoal composite. The fire-retardancy of overlaid charcoal composite in fire test was affected by an interaction of charcoal wood species and the percentage of additional borax. The optimal fire-retardancy properties were shown by sengon timber overlaid with 5% borax added charcoal composite from Asam.
Bonding Performance of Maltodextrin and Citric Acid for Particleboard Made From Nipa Fronds
Mahdi Santoso,Ragil Widyorini,Tibertius Agus Prayitno,Joko Sulistyo 한국목재공학회 2017 목재공학 Vol.45 No.4
Maltodextrin and citric acid are two types of natural materials with the potential as an eco-friendly binder. Maltodextrin is a natural substance rich in hydroxyl groups and can form hydrogen bonds with lignoselulosic material, while citric acid is a polycarboxylic acid which can form an ester bond with a hydroxyl group at lignoselulosic material. The combination of maltodextrin and citric acid as a natural binder materials supposed to be increase the ester bonds formed within the particleboard. This research determined to investigate the bond-ing properties of a new adhesive composed of maltodextrin/citric acid for nipa frond particleboard. Maltodextrin and citric acid were dissolved in distillated water at the ratios of 100/0, 87.5/12.5, 75/25 and 0/100, and the concentration of the solution was adjusted to 50% for maltodextrin and 60% citric acid (wt%). This adhesive solution was sprayed onto the particles at 20% resin content based on the weight of oven dried particles. Particleboards with a size of 25 × 25 × 1 cm, a target density 800 kg/m<sup>3</sup> were prepared by hot-pressing at press temperatures of 180℃ or 200℃, a press time of 10 minute and board pressure 3.6 MPa. Physical and mechanical properties of particleboard were tested by a standard method (JIS A 5908). The results showed that added citric acid level in maltodextrin/citric acid composition and hot-pressing temperature had affected to the properties of particleboard. The optimum properties of the board were achieved at a pressing temperature of 180℃ and the addition of only 20% citric acid. The results also indicated that the peak intensity of C=O group increased and OH group decreased with the addition of citric acid and an increase in the pressing temperature, suggesting an interreaction between the hydroxyl groups from the lignocellulosic materials and carboxyl groups from citric acid to form the ester groups.
( Tomy Listyanto ),( Hanan Purana Putra ),( Ganis Lukmandaru ),( Joko Sulistyo ),( Sugi Purwanto ),( Nam Hun Kim ) 한국목재공학회 2018 한국목재공학회 학술발표논문집 Vol.2018 No.1
The aim was to investigate the effect of girdling duration on durability and mechanical properties of 12 years old fast growing teak. Samples were obtained from 12- years old fast growing teak. Four girdling durations, which were 0 month, 3 months, 9 months and 12 months, were applied before harvesting Samples from heartwood and sapwood were tested against dry wood termites for four weeks. The observed parameters were mortality and mass losses. Modulus of Rupture (MoR) and Modulus of elasticity (MoE) were measured to examine the mechanical properties. The data were then tested using variance analysis with significantly level of 5 % and continued by Honestly Significant Difference Tukey to find the difference. The result showed that the durability class against dry wood termites of heartwood among girdling duration of 0 month, 3 months, 9 months and 12 months were class V, IV, II and II, respectively, while the sapwood one were class V, V, V and IV, respectively. The value of MoR and MoE increased slightly as the duration of girdling increased.
Sri Nugroho Marsoem,Fajar Setiaji,Nam Hum Kim,Joko Sulistyo,Denny Irawati,Widyanto Dwi Nugroho,Yus Andini Bekti Pertiwi 한국목재공학회 2015 목재공학 Vol.43 No.2
Fiber morphology and basic characteristics of Legi bamboos (Gigantochloa atter) growing on Yogyakarta were studied considering their age and height positions in the culms. Culms of 4, 16, and 40 months were harvested, and their total lengths were measured. The length, diameter, and wall thickness of each internode were measured. All the sample culms were divided into three different parts along the height, and their fiber dimension and physical properties were observed. The data obtained were analyzed by analysis of variance. The results showed that the culms had a diameter of 5.8 to 10.8 cm. The lowest internodes always showed the shortest length and the thickest wall. The culms had an average fiber length of 2.41 mm and Runkel ratio of 0.61. Fiber length was affected by the height, while fiber diameter, lumen diameter, and fiber wall thickness were affected significantly by the age of the culms. The culms had high green moisture content (GMC) of 157.89%, and basic density (BD) of 456.67 kg.m -3 , a total longitudinal shrinkage of 0.35%, and relatively low R/T shrinkage ratio. The interactions between age and height were affected GMC and BD.
( Tomy Listyanto ),( Galihaji Saka Felix E. K. Sembiring Colia ),( Harry Praptoyo ),( Yus Andhini ),( Joko Sulistyo ) 한국목재공학회 2017 한국목재공학회 학술발표논문집 Vol.2017 No.1
This study was aimed to investigate the effects of various incising density and two type of drying schedules on drying characteristics of teak wood (Tectonagrandis, L.f). Three teaktrees with the diameter of 300-400 mm were cut and sawn into columns with the dimension of 100 x 100 x 5000 mm. Each columnwas cut into five parts with the length of 500 mm. A total of 50 columns with the dimension of 100 x 100 x 500 mm, were used for drying samples. A small sample with the dimension of 20 x 20 x 25 mm was taken in between drying sample to measure initial moisture content. Mechanical incisicing was applied to the the drying sample. Four various incising densities, which were 0, 500, 1000, and 1500 holes/m², were applied to the drying samples. Samples were dried with two different drying schedules, which were low and high temperature, until the moisture content of 12%. Five samples for each factor were used as replication. To evaluate the drying quality, drying rate, defects, and moisture distribution were measured. Static bending test was performed to investigate the strength properties. The results indicated that incising densities of 1500 holes/m² and high-temperature drying could significantly improve drying rate without significants defects. No significant decrease of strength properties among five incising densities was found in this research.