Bark from trees is considered a worthless raw material. However, this resource could be economically beneficial if utilized efficiently due to its rich chemical compounds. In this study, an ethanol toluene-soluble extractive, alpha-cellulose and lignin obtained from Leucaena leucocephala bark were characterized to determine their chemical functional groups. Based on FTIR spectral analysis, the results indicated that the bands of the functional groups of the extractive from the original bark remain unchanged; however, the absorbance intensity was found to be weaker in the group frequency and fingerprint regions. Removal of extractive, pectin, hemicellulose and lignin from the bark indirectly increased the strong absorbance intensity of cellulose. Broad peaks of OH stretching found in all spectra were assigned to the presence of phenolic OH and aliphatic structures for extractive and aromatic structures of lignin. It was revealed that aromatic functional groups were mainly found in the extractive, while water, carbonyl and ether were the dominant groups in cellulose, and methyl, methylene, carbonyl and carboxyl groups were enriched in lignin. Graphic abstract

Effect of oil heat treatment on physical properties of 3 years old Gigantochloa scortechinii Gamble bamboo was investigated. The bamboo splits within epidermis were heat-treated using crude palm oil at temperature 140°C, 180°C and 220°C for duration 30 and 60 min. The objectives were to determine the effect of oil heat treatment on physical properties of the heat-treated bamboo and to assess any significant changes on physical properties of the heat-treated bamboo. Untreated bamboo was used as comparison for each treatment conditions. The results indicated equilibrium moisture content (EMC), density and volumetric shrinkage of heat-treated bamboo decreased as the treatment temperature and time increases. The EMC and density reduction were 4-27% and 11-18% approximately. This study indicated that bamboo became less hygroscopic when subjected to higher temperature and longer heat treatment time. Volumetric shrinkage of bamboo was also reduced by the treatment conditions (17-53%). The shrinkage properties of bamboo were inversely proportional to the treatment conditions, indicating that oil heat treatment successfully imparts the dimensional stability of the bamboo.

Effect of oil heat treatment on chemical constituents of 3 years old Gigantochloa scortechinii Gamble bamboo was investigated. The bamboo splits within epidermis were heat-treated using crude palm oil at temperature 140°C, 180°C and 220°C for duration 30 and 60 min. After removed the epidermis, the samples were then grind to pass a BS 40-mesh sieve and retained on a BS 60-mesh sieve. The sawdust was air dried for several days before conducted to chemical analyses (cellulose, hemicellulose and lignin) based on TAPPI Standard Methods. The colorimetric method devised by Humprey and Kelly (1960) was adapted to analysis starch in bamboo. Reading was obtained through Baush Lomb UV Spectrophotometer at 650 µm calculated by standard reference using A.R. potato starch. Control was used as comparison for each type of test conducted. There was no significant different between control and condition at 140°C for 60 min (81.4%) of holocellulose content. The value was decreased by 2.1 to 10.7% (79.7 to 72.7%) after heating at 180 to 220°C for 30 to 60 min. The hemicellulose content of bamboo was ranged 24.1 to 27.8% after heating at 140-220°C for 30 to 60 min. The cellulose content of heat-treated bamboo was ranged 47.4 to 55.2% after reduced about 2 to 14%. Lignin content increased about 16% (26%) at 220°C/60 min after reduced approximately 1 to 5% at 140 to 180°C for 30 to 60 min. Starch content was largely reduced about 2 to 54% (4 to 1.9%) at 140 to 180°C for 30 to 60 min of treatment. The results indicated that degradation of cellulose and hemicellulose of heat-treated bamboo was attributed to plasticization of lignin during heating in the same time hydrolysed the starch content.

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Microwave-induced in-situ catalytic co-pyrolysis of empty fruit bunch (EFB) with truck tire (TT) using a low-cost heterogeneous catalyst to produce aromatic-rich pyrolytic oil is proposed. In this study, the effect of catalyst type and catalyst-to-feedstock ratio were investigated. Three types of catalysts were used, namely activated carbon (AC), clay (CL)