Identification and Evaluation of Antioxidant Activities of Bamboo Extracts

The antioxidant activity of solvent extracts from two main bamboo species, moso bamboo (Phyllostachys pubescens) and madake bamboo (P. bambusoides) in Japan, was first evaluated by scavenging free radical of 1,1-diphenyl-2-picrylhydrazyl (DPPH), the inhibition activity for peroxidation of linoleic acid, and the reduction power. The methanol-extracts of moso bamboo culms and madake bamboo leaves presented stronger antioxidant activity compared with DPPH scavenging activity. Methanol-extract of moso bamboo culms was further fractionated by different solvents and n-butanol soluble fraction exhibited the most significant activity in the DPPH scavenging assay. The fractionation of n-butanol soluble extract was isolated by silica gel column with gradient mixture solvent of chloroform and methanol. The isolated fractions were directed by the antioxidant activity measured by scavenging the stable DPPH free radical. It was observed that most of the eluted fractions showed the antioxidative activity. Fractions acquired from elution with the mixture solvent of chloroform and methanol (10:1–5:1) showed stronger antioxidant activity than the other fractions.

Secondary Activation of Commercial Activated Carbon and its Application in Electric Double Layer Capacitor

The cheap commercial activated carbon (AC) was improved through the secondary activation under steam in the presence of FeCl2 catalyst in the temperature range of 800-950℃ and its application in electric double layer capacitors (EDLCs) with organic electrolyte was studied. The re-activation of AC results in the increases in both specific capacitance and high rate capability of EDLCs. For AC treated under optimized conditions, its discharge specific capacitance increases up to 55.65 F/g, an increase of about 33% as compared to the original AC, and the high rate capability was increased significantly. The good performances of EDLC with improved AC were correlated to the increasing mesoporous ratio.

Same Recovery Level of Compressed Chinese Fir Wood Can Be Obtained Through Different Heating Fixation Pathways

The recovery of compression set (RS) of wood after dry heating or steam treatment mainly depends on the temperature and time of treatment. For quantitative elucidation, a graph of intermediate RS was built with temperature (T) and time (t) as coordinates. In this graph (abbreviated as T-t planum), a series of curves of RS were created. This leads to a conclusion that same RS can be obtained by numerous different pathways. Further research on pathway equivalency based on T-t planum indicates that a low RS of 10% can be achieved definitely by different combinations of time and temperature. However, the fixation mechanism varies at different temperatures. On the equivalent pathways of higher recovery, the influence of temperature must be taken into consideration. The actual routes must be somewhat modified to achieve an expected result. This makes it possible for us to work out a best fixation pathway among all the possibilities, to eliminate the impact of heat on the mechanical properties of wood.

Properties of Esterified Wood Prepared with Maleic Anhydride/Tetrabr Omophthalic Anhydride/Glycerol Mixture

For overcoming disadvantages of wood, an esterification process was employed and tetrabromophthalic anhydride (TBPA) was used as a reactive chemical agent to prepare an esterified wood with the high dimensional stability, flame resistance, and resistance to biodegradation from water-leaching. The experimental results indicated that esterification of wood plus maleic anhydride / tetrabromophthalic anhydride / glycerol could endow wood with dimensional stability, the antiswelling efficiency during water absorption (ASEw), reduction in water absorptivity (RWA), antiswelling efficiency during moisture absorption (ASEm), moisture excluding efficiency (MEE), and oxygen index (OI) of treated wood increased with an increase in the weight percent gain (WPG). And the treated wood showed great decay resistance and resistance to water leaching, too.

Changes of Chemical Composition and Crystalline of Compressed Chinese Fir Wood in Heating Fixation

The changes in relative crystalline, chemical composition and internal structure of compressed Chinese fir wood after different heating fixations were found strictly related to fixation conditions. The compressed wood powders were fixed either by heating at different temperatures all resulting in a 10% recovery, or by incubating at 180 °C for different periods with subsequent recovery levels. Both X-ray diffraction and infrared absorption of those samples have been measured. Relative crystalline increases at early stage of heating fixation, and then decreased gradually. Hemicellulose and lignin decomposition were induced by the fixation process, especially at 180 °C, and lignin was degraded actively. Furthermore, absorbed water was lost after heating, but cellulose did not change markedly. Although different fixation pathways can result in the same recovery level, the major chemical reactions un- derlying them vary, which is consistent with the difference of fixation mechanisms.