Chemical composition and potential uses of Leucaena leucocephala stem bark

Leucaena leucocephala stem bark that was eleven years old was studied for its chemical composition and usage. The samples were subjected to chemical analyses based on ASTM standard procedures after being air-dried for several days. The results found that the bark of L. leucocephala has a pH value of 6.04 and that the solubility of the bark in 1% NaOH alkali is the highest compared to the solubility in hot water (14.45%) and cold water (14.36%), while the chemical composition of the bark of L. leucocephala was ash (15.76%); extractives (8.39%); holocellulose (132.85%); hemicellulose (103.66%); cellulose (29.19%) and lignin (38.24%). Based on the findings, L. leucocephala bark was less acidic. When used as a source of carbohydrates, bark has a high solubility, and its chemical composition may have an impact on how quickly it burns when it is pyrolysed.

Dynamic relationship between mechanical properties and chemical composition distribution of wood cell walls

Wood is a natural composite material with a complex structure. Its mechanical properties are mainly due to the cell walls. In order to investigate the relationship between mechanical properties and chemical composition of wood cell wall. Nanoindentation and Raman imaging were used to characterize the longitudinal mechanical properties and chemical composition distribution of wood fibers of three years old fast-growing poplar (Populus×euramericana cv. ‘74 /76’) during the growing season at different times. The results were showed that the content and distribution of cellulose and lignin are closely related to the mechanical properties of wood fiber cell walls, especially the cellulose for the longitudinal elastic modulus and the lignin for the hardness of cell walls. It was also demonstrated that the longitudinal elastic modulus and hardness of the secondary wall 2 layer (S2) were strongly correlated to the micro fibril angle (MFA) and crystallinity of cellulose during the active phase.

Changes in physical-mechanical properties and chemical compositions of Toona sinensis wood before and after thermal treatment

Vacuum heat treatment was used to improve the dimensional stability of Toona sinensis wood in this study, the shrinking and swelling rates, the physical-mechanical properties, and the chemical compositions before and after the thermal treatment were evaluated. The results revealed that the volume shrinkage and swelling rate for the heat-treated wood samples were decreased by 45.60% and 49.95%, respectively at 220°C for 6 h indicating that thermal treatment could obviously improve the dimensional stability of Toona sinensis wood. Thermal treatment also decreased the mechanical strength. The surface color was changed by the treatment. The chemical composition results showed the decrease in density and mechanical strength was due to the partial degradation of hemicellulose during the treatment. The results of this study that vacuum heat treatment could improve the dimensional stability by sacrificing somewhat mechanical strength, the treatment conditions mainly the temperature should be properly controlled to archive an optimized improvement in dimensional stability with minimum reduction in mechanical strength.

Comparison of fibre from maize stalk domains and sugar cane bagasse

The aim of this study is to investigate properties of pulverised cellulosic material from parts of maize stalks and sugar cane bagasse (SCB). Both materials were foremost subjected to a cutting mill before boiling with water. The chemical compositions and mechanical properties of the maize stalk residues and sugar cane bagasse were performed using a TAPPI standard. Optical microscope, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Ultraviolet-visible spectroscopy (UV-Vis) were used to characterise the materials. Rind displays thinner and longer fibres, which are less unequal and almost quadrangular. In fact, it has a highest crystallinity trailed by nodes and sugar cane bagasse in sequence. Interestingly, thermal stability of SCB is dominating followed by rind and nodes.

Characteristic features of the oil-heat treated woods from tropical fast growing wood species

This study aimed to evaluate the effect of oil-heat treatment on the anatomical, physical, and chemical properties of the tropical fast-growing wood species as gmelina (Gmelinaarborea) and mindi (Melia azedarach) wood. Vessel lumen area and diameter in radial and tangential direction of both species increased with increasing temperature. The fiber lumen areas in both woods were remarkably decreased by oil-heat treatment, and the fiber wall area increased considerably with increasing temperature. Both woods tended to gain weight after heat treatment at 180°C and 200°C, and then lose weight after heat treatment at 220°C. The density of mindi increased greatly at 180°C and 200°C and slightly decreased at 220°C. The dimension of the specimens in tangential direction increased with heat treatment, but the rate decreased with increasing temperature. The relative crystallinity and crystallite width of the heat-treated woods were greater than those of the untreated wood. In the Fourier transform infrared analyses, the peaks from the carbohydrates were changed after oil-heat treatment, mainly due to the degradation of hemicellulose. Consequently, it was revealed that the heat treatment affected various properties of gmelina and mindi woods. Differing characteristics between the species were also noted.

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.