WOOD RESEARCH Volume 68, Number 3, 2023
Sarah Augustina, Wahyu Dwianto, Muhammad Adly Rahandi Lubis, Ratih Damayanti, Danang Sudarwoko Adi, Jamaludin Malik, Imam Wahyudi, Wayan Darmawan, Philippe Gerardin, Sari Delviana Marbun, and Hiroshi Isoda

Effect of Anatomical Structure on Dimensional Stability of Low Molecular Weight Phenol-Formaldehyde Impregnated Wood

This research deals with low molecular weight-phenol formaldehyde (LMW–PF) impregnation on sepetir (Sindora spp), nyatoh (Palaquium spp.), and pisang putih (Mezzettia spp.) woods to determine the effect of different anatomical structure on weight percent gain and dimensional stability improvement. The wood samples were impregnated using LMW–PF solutions with 7, 8, 9, 10, and 11% of concentrations (w/w), vacuum-pressured (–98 kPa, 15 min, 350 kPa, 4 h), and re-immersed in 80°C for 3 h. According to the findings, LMW–PF impregnation reduced coefficient of swelling by 9.64–29.95%, and increased anti-swelling efficiency by 12.24–29.91%. Additionally, the water absorption and thickness swelling reduced by 2.43–38.75% and 15.94–34.21%, respectively, indicating the improvement of dimensional stability. Microscopy and NIR analysis revealed the presence and reaction of LMW–PF within porous wood matrix. The effect of diverse anatomical structures caused complexity on LMW–PF impregnation. Sepetir-treated wood with fewer anatomical barriers resulted in better dimensional stability improvement than others.

WOOD RESEARCH Volume 67, Number 6, 2022
Jamaludin Malik, Erlina Nurul Aini, Deazy Rachmi Trisatya, Sona Suhartana, Imam Wahyudi, and Sarah Augustina

Dimensional stability and durability of hybrid sandwich panel made from oil palm lumber, sengon and gmelina with boron-alum impregnation

In this study, sandwich panels made from oil palm lumber, sengon, and gmelina wood were impregnated with a boron-alum solution to improve their water and termite resistance. Water resistance testing was evaluated using a thickness swelling test following the method in SNI 03-2105. The sandwich panel was also tested for its durability against dry wood termites, according to SNI 01-7207. The weight loss, mortality, and attack degree were used as the parameters for evaluating termite durability. The results showed that the treatment with a boron-alum solution can increase the stability, water resistance, and weight loss properties up to 73%, 41%, and 100%, respectively. The best properties of the sandwich panel were obtained by the sengon-isocyanate panel with 8% boric acid-borax and 5% alum treatment which has thickness swelling of 2.37%, water absorption of 49.04%, weight loss of 0.0124%, termite mortality of 100%, and attack degree of 0.

WOOD RESEARCH Volume 66, Number 5, 2021
Sarah Augustina, Imam Wahyudi, Wayan Darmawan, Jamaludin Malik, Naoki Okano, Taiyo Okada, Kazushige Murayama, Hikaru Kobori, Yoichi Kojima, and Shigehiko Suzuki

Selected properties of compregnated wood using low molecular weight phenol formaldehyde and succinic anhydride

The aim of this study was to investigate the effect of impregnating materials (low molecular weight phenol formaldehyde or LmwPF and succinic anhydride or SA), their concentrations (5 and 10%), and compression ratios (20 and 40% from initial thickness) on improvement of specific gravity (SG) and dimensional stability on nyatoh, sepetir, and pisang putih wood; and then compared them to control and densified wood. The results showed that SG and dimensional stability of compregnated wood were affected by all parameters studied. Higher compression ratio and concentration will result in a greater improvement. In general, SG and dimensional stability of compregnated wood were better than the control. SG of LmwPF- and SA-compregnated wood increased by 10.69‒22.31% and 6.96‒23.09%, respectively. Utilization of LmwPF and SA has significantly reduced the spring-back, but the latter is better. The compression-set recovery after compregnation was 18.34‒33.99%, while after densification was 47.86‒71.49%.

WOOD RESEARCH Volume 66, Number 4, 2021
Kidung Tirtayasa Putra Pangestu, Wayan Darmawan, Dodi Nandika, Imam Wahyudi, Lumongga Dumasari, and Hiroshi Usuki

Performance of coated tungsten carbide in milling composite boards

The purpose of this research was to analyze the performance (wear resistance, surface roughness, chip formation, and noise level) of AlCrN, TiN, and TiAlN coated tungsten carbides in cutting composite boards. The composite boards of wood plastic composite, laminated veneer lumber, and oriented strand board were cut by the coated tungsten carbide tools in a computer numerical control router. The results show that the differences in structure among the composite boards resulted in the difference in clearance wear, chip formation, surface roughness, and noise level phenomenon. The abrasive materials in wood plastic composite generated the highest clearance wear on the coated carbide tools tested. TiAlN coated carbide tool provided better wear resistance, smoother composite boards surfaces, and lower noise levels.