Chemical, Colour and Strength Changes of Eco-friendly Hot Oil Treatment on 15 Year-old Cultivated Acacia Hybrid

Abstract

The chemical, colour and strength properties of thermally modified cultivated 15-year-old Acacia hybrid were investigated. Logs of A. hybrid were harvested and cut at the bottom, middle and top sections. The wood later underwent hot oil thermal modification using palm oil at temperatures 180°C, 200°C and 220°C for 30, 60 and 90 min. Untreated wood was used as control. The hot oil thermal modification process caused some features changed in the chemical composition, colour appearances and strength properties of A. hybrid wood. Parameters such as temperatures and treatment time were closely monitored as they influence the chemical, colour and strength changes in the treated wood. Temperatures of 180°C, 200°C and 220°C, and treatment time of 1 hr, 2 hrs. and 3 hrs. were used in the study. The degradation in holocellulose, cellulose, and hemicellulose contents was recognized when acacia woods were exposed to oil thermally modified process. Holocellulose and celulose degraded with the increasing of treatment temperature and duration of heating exposure, while lignin showed the increment in content through this treatment. The colour changes in the sapwood and heartwood were measured using the Minolta Chroma-meter CR-310 and the results are presented according to the CIE L*a*b* colour coordinates system. The results show that temperature at certain treatment time enhanced and darkened the treated wood. The colour of the treated sapwood can be enhanced to match the colour of the natural A. hybrid heartwood. The strength properties of the oil heat treated A. hybrid wood decreases in values of both MOR and MOE throughout the treatment process. The decreases in values were influenced by temperature and duration of the treatment.

Effect of Combined Steam and Heat Treatments on Extractives and Lignin in Sapwood and Heartwood of Turkey Oak (Quercus cerris L.) Wood

“…These results have also been reported by Wahab et al (2011). Kamdem et al (2002) have suggested that the increase in lignin conten is probably due to the reduction of other wood components and does not imply that new lignin is formed.…”

“…4), the lignin contents were always greater in heartwood, with the only exceptions coming from samples treated only with heat (Ctrl+H120 and Ctrl+H180). Similar results were found by Wahab et al (2011) in Acacia hybrid wood treated with hot oil, where the lignin content of heartwood was greater than that in sapwood. The differences in chemical composition in the wood, in terms of extractives, cellulose, and hemicellulose (Cao et al 2012) content, could be due to the lignin concentration in sapwood and heartwood.…”

<i>Tectona grandis</i>: Examine an Ultrastructure on Cultivated Teakwood due to the Scanning Electron Microscopy Enhanced by Heat Treatment

“…Next, the teak wood was put into a metal cage and then submerged into the heated oil. The whole process was monitored by a control panel outside the machine [24,25,26]. Once treated, the wood is then removed from the tank, and the residual oil is wiped clean with a cloth to prevent oil absorbance into the wood.…”

Chemical properties of modified mahogany wood by heat treatment

“…Penurunan kadar holoselulosa tersebut lebih besar dibandingkan di Pinus calibria yang dipanaskan pada suhu 130-230°C dalam waktu 2 dan 8 jam maupun kayu Mongolian pada suhu 240°C (Ding et al, 2011). Kisaran nilai penurunan kadar selulosa dan hemiselulosa sesuai pada kayu Acacia hybrid dengan perlakuan suhu 220°C selama 90 menit (Wahab et al, 2011).…”