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1.
For enhancing fire-resistant properties, a binary system to prepare wood-inorganic composites was studied by adding sodium methoxide (SM) or sodium acetate (SA) to a reaction system for SiO2 composites. Compared with the SiO2 composites, both the Na2O-SiO2 composites prepared could be greatly improved up to 600°C-700°C (glowing). From scanning electron microscopic observations, this enhanced fire resistance was assumed to be due to chemical and physicochemical effects, such as dehydration and carbonization of wood by Na2O gel. The glassy layer and intumescent structure formed over the cell walls were thought to prevent oxidation and heat transfer from proceeding into the inner portion of the wood cell walls. However, the reaction medium with SM to prepare Na2O-SiO2 composites was basic, whereas that with SA was rather neutral. In addition, in the latter composites, most of the inorganic gel was formed within the cell wall, retaining the porous structure characteristic of wood. Therefore, the Na2O-SiO2 composites prepared with SA can be concluded to be preferable for practical purposes.Part of this report was presented at the 50th annual meeting of the Japan Wood Research Society, Kyoto, April 2000 相似文献
2.
Summary A study of the wood-inorganic composites prepared by the sol-gel process with a metal alkoxide indicated that an inorganic modification of wood with TiO2 gels from tetraisopropoxytitanium (TPT) can not improve its properties due to the formation of the gels in the cell lumina by high hydrolysis rate of TPT. In this study, therefore, titanium alkoxides or titanium chelates which have the lower rate of hydrolysis and subsequent polycondensation than TPT were used for preparing TiO2 wood-inorganic composites to study the topochemical effects of the TiO2 gels for the property enhancement of wood. As a result, it was found by SEM-EDXA analysis that the TiO2 gels deposited within the cell walls could improve the properties of wood in dimensional stability and fire-resistance, whereas for the gels in the cell lumina, property enhancement could not be achieved, as observed in SiO2 wood-inorganic composites.This research has been performed in Dept. of Wood Sci. & Technol., Kyoto UniversityThis research was supported by a Grant-in-Aid for Scientific Research (B) (No. 06453176, 1994.4–1996.3) from the Ministry of Education, Science, and Culture, Japan. The authors were grateful to Nippon Soda Co., Ltd. for providing titanic reagents. 相似文献
3.
To enhance the photostability of wood against ultraviolet (UV) light, a UV absorbent, 2,2,4-trihydroxy-4-[2-hydroxy-3-(3-trimethoxysilylpropoxy)propoxy]benzophenone (BP), was applied to the reaction system for preparing SiO2 wood–inorganic composites by sol–gel reaction. The BP–SiO2 wood–inorganic composites obtained were examined for photostability by scanning electron microscope observations, color changes, and diffuse reflectance infrared fourier transform analyses. The results clearly indicated that compared with SiO2 composites, BP–SiO2 composites improved the photostability of wood. In addition, BP was stable against UV light without degradation so that the BP–SiO2 composite should provide sustainable and high photostability of treated wood.Part of this report was presented at the 51st Annual Meeting of the Japan Wood Research Society at Tokyo, April, 2001 相似文献
4.
The representative carbon footprint of product (CFP) value of “certified wood in Kyoto Prefecture” was calculated as 241?kg-CO2/m3. The CFP value was 158?kg-CO2/m3 when wood was not kiln dried and final processing was not involved, whereas that of “kiln-dried, finished wood” was 284?kg-CO2/m3. Comparisons of different types of wood were also conducted to examine CO2 emission-reducing effects of “certified wood in Kyoto Prefecture”. We compared the CFP of lumber produced (in Japan) from logs supplied from Japan and other countries and that of “certified wood in Kyoto Prefecture”; the lumber products as a target for comparison are shipped to markets throughout the country. The CFP of “certified wood in Kyoto Prefecture” was approximately 50% lower compared to that of North American wood lumbered in Japan and shipped to markets throughout the country, and about 30% lower compared to the mean CFP of lumber produced (in Japan) from logs supplied from Japan and other countries and shipped to markets throughout the country. We then compared the CFP of “products imported from other countries after being cut into lumber” to that of “certified wood in Kyoto Prefecture”. The CFPs of lumber products from North America and Europe were lower than that of “certified wood in Kyoto Prefecture” (kiln-dried, finished wood). However, when only woodchips were used as a heat source in the process of kiln drying, the CFP of “certified wood in Kyoto Prefecture” was lower than any other kiln-dried lumber products. Regarding “certified wood in Kyoto Prefecture”, the use of woodchips as a heat source in the process of kiln drying or a shift to air drying decreases the CFP. 相似文献
5.
Wood polymer nanocomposites (WPNC) based on nano-SiO2 were prepared by impregnation of styrene acrylonitrile copolymer (SAN), SiO2 nanoparticles modified with γ-trimethoxy silyl propyl methacrylate (MSMA), and nanoclay into wood. The structure of modified SiO2 nanoparticles and WPNC was characterized by Fourier transform infrared spectroscopy (FTIR). XRD analysis showed the delaminated structure of SAN/SiO2/clay-treated wood composites. The synergistic effect of nano-SiO2 and nanoclay was investigated. Thermal stability of SiO2 nanoparticles decreased after modification, while that of wood treated with SAN, SiO2, and nanoclay improved. Morphological characteristics were examined by scanning electron microscopy (SEM). Mechanical properties, water uptake (%), dimensional stability, hardness, and flammability were found to improve due to incorporation of SiO2 and nanoclay into wood polymer composites. Maximum improvement in properties was observed in the wood polymer composites containing SiO2 and nanoclay at the ratio of 1:1. 相似文献
6.
7.
柠檬桉木材中二氧化硅的分布和含量的测定 总被引：5，自引：0，他引：5
生物矿化所形成的木材-无机质复合材是当前木材科学研究的热点之一，要实现木材一无机质复合材的人工模拟，其关键还在于研究和探讨木材生物矿化的机理，因此要对木材中无机物的分布及其含量进行研究，从而获取生物矿化所形成的木材一无机质复合材料的形成机理，以此来指导木材的生物改性或木材一无机复合材的仿生合成。本研究采用光学显微镜对柠檬桉木材中二氧化硅的分布进行观察，得出柠檬桉木材中二氧化硅主要分布在射线细胞中，同时大量的晶体存在于轴向薄壁细胞中，早材中的硅石多于晚材中的硅石。采用重量法对木材轴向分布、径向分布中灰分和二氧化硅的含量进行的分析表明：柠檬桉木材中灰分和二氧化硅的含量随着高度的增加而降低，柠檬桉木材灰分和二氧化硅的含量从边材部位向心材部位逐渐减少。 相似文献
8.
In order to improve wood properties of triploid clones of Populus tomentosa, urea-formaldehyde (UF) resin was compounded with nano-SiO2, coupling agents and flame retardants in different ways to prepare five kinds of modifiers. The poplar wood samples were
impregnated with the modifiers and heated to prepare UF-SiO2-wood composites. The antiswelling efficiency, resistance of water absorption, oxygen index and hardness of the composites
were measured. Results show that all of the modifiers reduced water absorption of poplar wood and enhanced flame resistance
and hardness. Nano-SiO2 showed a marked effect in improving the hardness of wood. In addition, all of the modifiers, except UF-C-SiO2-polymer, improved the dimensional stability of poplar wood. The UF resin and nano-SiO2 compound improved general properties of poplar wood.
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Translated from Journal of Beijing Forestry University, 2006, 28(2): 123–128 [译自: 北京林业大学学报] 相似文献
9.
Modification of wood with silicon compounds. Treatment systems based on organic silicon compounds — a review 总被引：1，自引：0，他引：1
A wide variety of organo-silicon compounds has been described for application on wood. Some compounds such as organo-functional silanes which are mostly applied in combination with tetraalkoxysilanes (sol-gel process) as well as chlorosilanes and trimethylsilyl derivatives were proposed for a full impregnation treatment of wood. Other systems have been developed for surface treatment of wood such as plasma coating with hexametyldisiloxane and micro-emulsions which mainly contain silane/siloxane mixtures. The effects related to the various treatments vary from an increase in dimensional stability, durability and fire resistance to an enhanced hydrophobation of wood. In the cases of decay and fire resistance a combination of silicon based systems with other chemicals was required to obtain satisfactory results. Due to the excellent water repellent ability and weathering stability of some treatments, application of silicon treated wood under conditions of hazard class III (EN 335 outside above ground exposure) is recommended.Abbreviations ASE anti-shrink efficiency - ATR-FT-IR attenuated total reflectance — Fourier transform infrared spectroscopy - CP MAS-NMR cross polarisation magic angle spinning nuclear magnetic resonance spectroscopy - DTA differential thermal analysis - DTMOS decyltrimethoxysilane - EDX energy dispersive x-ray analysis - EETMOS -(3,4 epoxycyclohexyl) ethyl trimethoxysilane - EMC equilibrium moisture content - ESCA electron spectroscopy for chemical analysis - HFOETMOS 2-heptadecafluorooctylethyltrimethoxysilane - HMDSO hexamethyldisiloxane - IPTEOS 3-isocyanatepropyl triethoxysilane - MPTMOS -methacryloxypropyl trimethoxysilane - MTMOS methyltrimethoxysilane - PDMS polydimethylsiloxane - PTMOS propyltrimethoxysilane - TEOS tetraethoxysilane / triethyl orthosilicate - TFPTMOS 3,3,3-trifluoropropyltrimethoxysilane - TGA thermo-gravimetric analysis - TMSAH 3-(trimethoxysilyl)propyl (carboxymethyl) decylmethyl ammonium hydroxide inner salt - TMSCl trimethylsilyl chloride - TPT tetraisopropyl titanate - VTMOS vinyl trimethoxysilane - WPG weight percent gain - WRE water repellent efficiency 相似文献
10.
An effort was made to develop photocatalytic TiO2 crystallite–activated carbon (TiO2-AC) composites from tetraisopropyl titanate (TPT)-soaked activated carbon in supercritical isopropanol. It was subsequently
found that TPT in supercritical isopropanol could be effectively converted to the anatase form of the TiO2 crystallites. The prepared composites, composed of activated carbon as an adsorbent and the anatase form of TiO2 as a photocatalyst, were evaluated for their adsorption capacity and subsequent photocatalytic activity against formaldehyde,
one of the harmful air pollutants in the environment. As a result, the supercritically treated TiO2–AC composites, particularly at 300°C and 350°C, had much higher formaldehyde-decomposing ability compared to a noncomposite
comprising a simple mixture of activated carbon and TiO2 granules. This indicates that the supercritical treatment can be effective for preparing the photocatalytic composites that
have a high synergetic effect of adsorption and photocatalytic decomposition of formaldehyde for environmental cleaning.
Received: May 18, 2001 / Accepted: March 8, 2002
On leave from Fujian Forestry College, Fujian 353001, P.R. China
Acknowledgments The authors express their sincere thanks to Miss H. Tokoro and Mr. D. Kusdiana for their kind, valuable help and cooperation
and to Dr. H. Miyafuji for SEM observations of samples, all at the Graduate School of Energy Science, Kyoto University.
Correspondence to:S. Saka 相似文献
11.
Nanoscale in Wood,Nanowood and Wood—Inorganic Nanocomposites 总被引：4，自引：0，他引：4
ZhaoGuangjie LuWenhua 《中国林学(英文版)》2003,5(1):44-48
In order to introduce nano science and technology(NST) into the research field of wood science and technology,and promote the research of wood science and wood-inorganic composites to nanoscale ,some new concepts,such as the nano space in wood,nano structure units of wood and nanowood are put forward in this paper based on the layer structure of wood cell wall and the pile-up model of its main components.Furthermore,the process of preparing nanowood is discussed,and wood-inorganic nanocomposites may be operated in three ways with wood (matrix) and inorganic filler phase in 0-2,0-3 or 2-3 dimensions respectively.The following results are obtained:(1) The nanoscale voids in wood indicate that wood has inherent space to accommodate nanosized materials,such as nanoparticles,nanotubes and nanosticks;(2) According to the size from top down,the nano structure units in wood can be classified as :nanolayers,nano CMF (cellulose microfibril) and matrixd,nano crystallite units and cellulose chain clusters,and these can theroretically from nanowood;(3) The preparation of wood-inorganic nanocomposites can be operated on 0-2,0-3 or 2-3 dimensions. 相似文献
12.
要实现木材-无机质复合材的人工模拟,其关键还是在于研究和探讨木材生物矿化的机理,因此要对木材中无机物的情况进行研究,从而获取生物矿化所形成的木材/无机质复合材料的形成机理,以此来指导木材的生物改性或木材/无机复合材的仿生合成。本文采用光学显微镜对几种木材/二氧化硅生物矿化复合材中硅石的分布进行观察发现:硅石主要分布在木射线细胞中,大量的晶体在木射线细胞以及轴向薄壁细胞中均有分布;采用重量法对几种木材/二氧化硅生物矿化复合材中二氧化硅含量情况进行测定表明:子京、山油柑、柚木、柠檬桉、山竹子等5种木材/二氧化硅生物矿化复合材中二氧化硅含量分别为1.5106%、0.8941%、0.8654%、0.2155%、0.1676%。 相似文献
13.
The aim of this research was to synthesize surface-treated nano-titanium dioxide (TiO2) particles and incorporate them into water-based acrylic systems, which could offer long-term protection for UV-sensible wood substrates. To suppress the photocatalytic activity, the surface of TiO2 nanoparticles in rutile crystal structure was coated with amorphous silica (SiO2) layer. The amounts of SiO2 were 5 and 10 wt%, respectively. Formation of SiO2 layer on TiO2 surface was analyzed using scanning and transmission electron microscopy. SiO2 layer thickness increases as a function of precursor loading. In addition, the influence of SiO2 loading on rutile UV-protective properties was determined. Transparent UV-protective coatings were developed by incorporating surface-treated nano-TiO2 into water-based acrylic stain. The particle size distribution was determined using dynamic light-scattering measurements, which indicate that the suspension of surface-treated rutile is stable against agglomeration. Furthermore, the color change and ability of protection against UV light of coatings after nanoparticles incorporation were determined. TiO2, surface treated with 10 wt% of SiO2, yielded coatings of higher transparency; however, TiO2, surface treated with 5 wt% of SiO2, improved UV protection. 相似文献
14.
Caroline Narayan Paulo M. Fernandes Jo van Brusselen Andreas Schuck 《Forest Ecology and Management》2007
The current paper analyses the potential for prescribed burning techniques for mitigating carbon dioxide (CO2) emissions from forest fires and attempts to show quantitatively that it can be a means of achieving a net reduction of carbon emissions in the context of the Kyoto Protocol. The limited number of available studies suggests that significant reductions in CO2 emissions can be obtained and that prescribed burning can be a viable option for mitigating emissions in fire-prone countries. The present analysis shows that the potential reduction attained by prescribed burning as a percentage of the reduction in emissions required by the Kyoto Protocol varies from country to country. Out of the 33 European countries investigated, only in one the requirements of the Kyoto Protocol could potentially be achieved by applying prescribed burning, while three other nations showed a potential net CO2 emissions reduction of about 4–8% of the Kyoto requirements and the majority showed a reduction of less than 2%. This implies that prescribed burning can only make a significant contribution in those countries with high wildland fire occurrence. Over a 5-year period the emissions from wildfires in the European region were estimated to be approximately 11 million tonnes of CO2 per year, while with prescribed burning application this was estimated to be 6 million tonnes, a potential reduction of almost 50%. This means that for countries in the Mediterranean region it may be worthwhile to account for the reduction in emissions obtained when such techniques are applied. 相似文献
15.
The effects of physical properties of wood, including specific gravity, porosity, and water retention, on the water activity (a
w) of wood meal media for the cultivation of edible mushrooms were examined. Five species of wood, selected from an initial set of 11 species, and six species of fungi popularly cultivated in Japan were used. The water activity of each fungal species was measured using liquid media in which a
w had been reduced by adding NaCl, KCl, sucrose, or ethylene glycol. From the water activities of the media and fungi, we estimated the most suitable wood species for the cultivation of each edible mushroom in wood meal media. Suitable wood species for the wood meal cultivation of shiitake, nameko, and maitake, which had relatively high a
w, was limited to hardwoods like arakashi, konara, and irohakaede because of their higher water activities. Edible mushrooms with lower levels of a
w, like hiratake, enokitake, and bunashimeji, could be cultivated in all kinds of wood species used in this experiment, but especially in sugi.Parts of this report were presented at the 49th, 50th, 51st, and 52nd Annual Meetings of the Japan Wood Research Society, in Kyoto (April 2000), Tokyo (April 2001), Gifu (April 2002), and Fukuoka (March 2003), Japan 相似文献
16.
Simon P. Whittock Gregory W. Dutkowski Bruce L. Greaves Luis A. Apiolaza 《Annals of Forest Science》2007,64(3):239-246
A system where carbon sequestration was directly dependent upon biomass production in a plantation was modelled to assess whether economic breeding objectives for the genetic improvement of Eucalyptus globulus were sensitive to potential revenues from carbon sequestration. Carbon dioxide equivalent accumulation in the biomass (CO2e) of the Australian E. globulus plantation estate established between 2004 and 2012 was estimated. Total carbon dioxide equivalent (CO2e) accumulation was in the order of ～146 t CO2e ha?1, of which 62 t CO2e ha?1 were tradable in 2012 (the 1st Kyoto Protocol commitment period) and a further 30 t CO2e ha?1 were tradable in 2016 (a hypothetical second Kyoto protocol commitment period). The correlated response of breeding objectives with and without carbon revenues (ΔcG h 1) never fell below 0.86 in sensitivity analysis, and the mean was 0.93. Where economic breeding objectives for the genetic improvement of Eucalyptus globulus for pulpwood plantations are based on maximizing net present value by increasing biomass production, the consideration of carbon revenues in economic breeding objectives will have no significant effect on the relative economic weights of the key economic traits, wood basic density and standing volume at harvest. 相似文献
17.
Influences of moisture content on the catalysis of sulfur dioxide and physical properties of reaction products were examined for a vapor-phase treatment of spruce wood with formaldehyde. The reaction rate was strongly dependent on the amounts of water and sulfur dioxide in the reaction system, and this was consistent with a proposal that the hydroxymethylsulfonic acid (HOCH2SO3H) formed from sulfur dioxide, water, and formaldehyde acts as a catalyst for the reaction. However, not all water molecules contributed to the formation of HOCH2SO3H, because some were adsorbed by the wood components. When the initial moisture content was high, polymeric cross-linking was likely because the ultimate weight gain was much greater than the value estimated based on monomeric cross-links. The lower values of antiswelling efficiency and higher equilibrium moisture content at a specific level of weight gain also suggested the existence of polymeric cross-links. However, the difference in the length of cross-links did not significantly influence the mechanical properties.Part of this research was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, April 2003 相似文献
18.
Takuyuki Yoshioka Kazuhiro Aruga Toshio Nitami Hiroshi Kobayashi Hideo Sakai 《Journal of Forest Research》2005,10(2):125-134
Using the method of a life cycle inventory (LCI) analysis, the energy balance and the carbon dioxide (CO2) emission of logging residues from Japanese conventional forestry as alternative energy resources were analyzed over the entire life cycle of the residues. The fuel consumption for forestry machines was measured in field experiments for harvesting and transporting logging residues at forestry operating sites in Japan. In addition, a total audit of energy consumption was undertaken. It involved an assessment of materials, construction, and the repair and maintenance of forestry machines as well as the costs associated with an energy-conversion plant. As a result, the ratio of energy output to input was calculated to be 5.69, indicating that the system examined in this study could be feasible as an energy production system. The CO2 emission per MWhe (e: electricity) of the biomass-fired power generation plant was calculated to be 61.8kgCO2/MWhe, while that of coal-fired power generation plants in Japan is 960kgCO2/MWhe. Therefore, the reduction in the amount of CO2 emission that would result from replacing coal with biomass for power generation by as much as 3.0 million dry-t/year of logging residues in Japan was estimated to be 1.66 million tCO2/year, corresponding to 0.142% of the national CO2 emission. This study provides evidence that Japan could reduce its domestic CO2 emission by using logging residues as alternative energy resources. 相似文献
19.
Thermal treatment of sawdust and coal-tar pitch mixture to produce porous carbon materials by chemical activation 总被引：1，自引：1，他引：0
Svetlana Ivanovna Tsyganova 《Wood Science and Technology》2013,47(1):77-82
In this work, different activated carbons were prepared from composites based on birch sawdust and coal-tar pitch by chemical activation with zinc chloride, phosphoric acid, and potassium hydroxide followed by carbonization. The influence of different chemical agents (ZnCl2, KOH, and H3PO4), final temperature of carbonization and media on yield and structural properties of the carbonic product was studied. It was shown that chemical agents allow increasing yield of carbonic residue. Composite modification by H3PO4 or ZnCl2 facilitates the formation of molded porous carbonic residue during the carbonization process. However, addition of KOH to the composite leads to formation of powder-like carbonic residue having a specific surface area of 1,600 m2 g?1 at 800 °C. It was established that all samples aged in air medium at 800 °C have higher values of specific surface area in comparison with the same samples aged in argon medium at similar conditions. 相似文献
20.
Simulated organic waste was biodegraded in a laboratory-scale machine using matrices prepared from four wood species to investigate the effects of wood species on the degradation rate and the bacterial community. The degradation rate, estimated by measuring weight loss and CO2 evolution, was found to be equal among the four wood species. Changes in viable cell counts and microbial communities over time were examined. Viable cell counts were also similar among the wood species, but initial bacterial communities differed owing to differences in wood species, although these communities became similar with time. The sensitivity of isolates to wood extractives was examined using paper discs. The extractive-insensitive bacteria species were dominant at the initial stage of biodegradation. However, occupancy of sensitive bacteria increased with time. It was thought that antibacterial extractives were degraded or inactivated after some time.Part of this report was presented at the 50th annual meeting of the Japan Wood Research Society, Kyoto. Japan, April 2000 相似文献