WOOD RESEARCH Volume 61, Number 3, 2016
Mehmet Yeniocak, Mehmet Colak, Osman Goktas, and Ibrahim Koca

Fire resistance performance of wood materials colored with eco-friendly pomegranate skin (Punica granatum) extracts

The main goal of this study was to determine fire resistance properties of wood treated with pomegranate extract and mordant mixes. According to that wood materials Scotch pine (Pinus sylvestris L.), Oriental beech (Fagus orientalis Lipsky) were chosen. Aluminum sulphate (KAl2(SO4)3.18H2O) copper sulphate (CuSO2.5H2O) and vinegar were used as mordant agent and a synthetic dye was used for comparison. Ultrasonic assisted method were used for extractionthe plant dyestuff from pomegranate skin (Punica granatum) and then applied to wood blocks by immersion (classic) and immersion ultrasonic assisted methods. The combustion test was realized according to ASTM-E 69-02 (2002) standard. The mass losses release of gasses (CO, O2) and the temperature differences of samples were detected for each 30 seconds during combustion. The results showed that the aluminum sulphate mixes were showed the best results on all tests. Unfortunately test performances are not enough to retard the fire effect on the wood materials. Eco-friendly natural colorant might be developed to use them as fire retardant.

WOOD RESEARCH Volume 64, Number 4, 2019
Wayan Darmawan, Muhammad Azhari, Istie S. Rahayu, Dodi Nandika, Rumanintya L. Putri, and Satoru Nishio Malela

The chips generated during up milling and down milling of pine wood by helical router-bits

Development of new helical edge router bits (helix angle 15°, 30°, 45°, and 60°) with a cutting circle diameter of 8 mm was studied. The purpose of the research work was to investigate chips formation and surface roughness characteristics in milling the pine wood by the straight and helical edge bits. The generated chips were classified in four types by sieving into spiral chip (5 mesh), flow chip (10 mesh), thin chip (30 mesh), and granule chip (< 30 mesh). The experimental results showed that the spiral chip was generated most often (on a weight percentage basis) by the bits during down milling process. More flow and thin chips were produced by the bits during up milling process. Better surface roughness was produced by bits during down milling compared to up milling. When the helix angle of the bits increased the amount of spiral and flow chips were increased and granule chip was reduced. The machined surface was better in roughness (lower Ra values) as the helix angle of the bits increased both in up milling and down milling processes.

WOOD RESEARCH Volume 64, Number 3, 2019
Shaoxiang Cai, Naihua Zhang, Kang Li, Yanjun Li, and Xinzhou Wang

Effect of pressurized hot water treatment on the mechanical properties, surface color, chemical composition and crystallinity of pine wood

The effect of a pressurized hot water treatment (PHWT) on the mechanical properties, chemical composition, surface color, and cellulose crystalline structure of Pine wood were examined in this study. The effects of PHWT of pine wood at 140, 160, 180, and 200°C for 1, 3 and 5 h were investigated in terms of changes in mechanical properties, chemical composition, surface color and cellulose crystallinity of pine wood by means of a GB/T standard, NREL LAP, Color Difference Meter, and X-ray diffraction (XRD). Both the temperature and treatment time showed significant effects. The results showed that the bending strength and elastic modulus decreased with an increasing temperature and duration. Changes in the chemical components and surface color occurred because of the degradation of the cellulose, hemicelluloses and lignin in the wood during the PHWT. Additionally, the relative degree of relative crystallinity of the samples increased. These findings demonstrated the potential of PHWT for the wood modification.