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1.
With montmorillonite (MMT) organically modified as organophilic MMT (OMMT) and water-soluble phenol formaldehyde resin (PF) as intermediate, Chinese fir (Cunninghamia lanceolata) wood/MMT nanocomposites (WMNC) were prepared via nano intercalation compounding and characterized by XRD, SEM and FTIR. Results show that: 1) the preparation of OMMT is very successful; 2) the self-made PF can effectively intercalate into MMT to increase markably its gallery distance and even exfoliate its nano silicate laminae; 3) the XRD analysis indicates that some exfoliated MMT enters the non-crystallized region of microfibrils in wood cell walls and the crystallinity degree of wood in WMNC decreases; 4) the SEM graphs show that multiform MMT exists in WMNC. Some grains block in wood cell lumen, some layers adhere to the wood surface of the inner cell wall and some exfoliated nanolaminae even insert into wood cell walls; and 5) the FTIR analysis suggests that MMT and wood in WMNC perhaps interact via certain chemical bonding. 相似文献
2.
Design of wood/montmorillonite (MMT) intercalation nanocomposite 总被引：4，自引：0，他引：4
Studying new wood composites through nano science and technology (NSC) will develop new compounding theory of wood, and accelerate the combination of new technology, wood science, material science and other disciplines. The compounding of wood and inorganic MMT on nanoscale molecular level has high potential to greatly improve the mechanical properties, fire retardance, abrasion resistance, decay resistance, dimensional stability and other properties of wood. Based on the great achievements of polymer/montmorillonite (MMT) nanocomposites, this paper reviewed nano intercalation compounding methods (i.e. in-situ intercalative polymerization and direct polymer intercalation), and discussed the structure, properties and modification of montmorillonite (MMT). According to the main chemical components and particular structure of wood, the authors discussed the liquefaction and plasticization of wood, compared the dissolvability and meltability between wood and polymer, and then systematically put forward the basic idea, technological processes and schematic diagram to prepare wood/MMT nanocomposites (WMNC). The key technology to prepare WMNC is either to introduce delaminated MMT nanolayers into wood with the help of some intermediate polymers, or to obtain liquefied wood or plasticized wood from the complicated natural composite. It is applicable and effective to realize wood/MMT nanoscale compounding with the help of proper intercalation agent and medium polymer through the proposed “one-step” or “two-step” impregnating processes. 相似文献
3.
LV Wenhua ZHAO Guangjie. Research Institute of Wood Industry Chinese Academy of Forestry Beijing P. R. China . College of Material Science Technology Beijing Forestry University Beijing P. R. China 《中国林业科技(英文版)》2006,5(1):33-39
INTRODUCTIONWood possesses many special properties, such asbeautiful grain, natural color, high strength-to-weightratio, good electricity and heat insulation; and it can beeasily processed, glued or dyed. It is biodegradable,recyclable and environmental-friendly (Wang Tianminet al. 2002). But as a biomaterial, it also has intrinsicdefects as easy decaying, burning and deforming,which largely limits its usage. Nano science andtechnology opens a completely new way to developwood composites… 相似文献
4.
Studying new wood composites through nano science and technology (NSC) will develop new compounding theory of wood, and accelerate the combination of new technology, wood science, material science and other disciplines. The compounding of wood and inorganic MMT on nanoscale molecular level has high potential to greatly improve the mechanical properties, fire retardance, abrasion resistance, decay resistance, dimensional stability and other properties of wood. Based on the great achievements of polymer/montmorillonite (MMT) nanocomposites, this paper reviewed nano intercalation compounding methods (i.e. in-situ intercalative polymerization and direct polymer intercalation), and discussed the structure, properties and modification of montmorillonite (MMT). According to the main chemical components and particular structure of wood, the authors discussed the liquefaction and plasticization of wood, compared the dissolvability and meltability between wood and polymer, and then systematically put forward the basic idea, technological processes and schematic diagram to prepare wood/MMT nanocomposites (WMNC). The key technology to prepare WMNC is either to introduce delaminated MMT nanolayers into wood with the help of some intermediate polymers, or to obtain liquefied wood or plasticized wood from the complicated natural composite. It is applicable and effective to realize wood/MMT nanoscale compounding with the help of proper intercalation agent and medium polymer through the proposed "one-step" or "two-step" impregnating processes. 相似文献
5.
Mariko Yoshioka Keiji Takabe Junji Sugiyama Yoshiyuki Nishio 《Journal of Wood Science》2006,52(2):121-127
New biodegradable cellulose acetate/layered silicate grafted poly(ε-caprolactone) [(CA/layered silicate)-g-PCL] nanocomposites were prepared by in situ polymerization of ε-caprolactone in the presence of cellulose acetate (CA) and organically modified layered silicate (OMLS). The structures of
the resulting composites were investigated. X-ray diffractometry was carried out to survey general structural features of
(CA/OMLS)-g-PCL nanocomposites, and revealed that OMLSs having hydroxyl groups in the organic modifiers greatly altered the layered silicate
structure by monomer intercalation and successive exfoliation through its polymerization. Two of the representative cases
were characterized by wide-angle and small-angle X-ray scattering analyses with a synchrotron source. The morphology of these
nanocomposites was further examined by transmission electron microscopy. When SPN, one of OMLSs having one hydroxyl group
in its modifier, was used, the silicate layers could not be dispersed thoroughly, but existed as aggregates consisting of
several silicate layers. Among them, the crystal growth of PCL developed by transcrystallization, where the crystal growth
was restricted in the confined space. When Cloisite 30B, having two hydroxyl groups within the modifier, was used, the silicate
layers forming the clay were dispersed completely in the composite and random orientation of the OMLS was observed. 相似文献
6.
In this study heartwood from a Chinese fir [Cunninghamia lanceolata (Lamb.) Hook] plantation was treated using a high-temperature drying (HTD) method at 115°C, a low-temperature drying (LTD)
method at 65°C, and freeze vacuum drying (FVD), respectively. The dynamic viscoelastic properties of dried wood specimens
were investigated. The measurements were carried out at a temperature range of −120 to 250°C at four different frequencies
(1, 2, 5, and 10 Hz) using dynamic mechanical analysis (DMA). We have drawn the following conclusions: 1) the storage modulus
E′ and loss modulus E″ are the highest for HTD wood and the lowest for FVD wood; 2) three relaxation processes were detected in HTD and LTD wood,
attributed to the micro-Brownian motion of cell wall polymers in the non-crystalline region, the oscillations of the torso
of cell wall polymers, and the motions of the methyl groups of cell wall polymers in the non-crystalline region in a decreasing
order of temperatures at which they occurred; and 3) in FVD wood, four relaxation processes were observed. A newly added relaxation
is attributed to the micro-Brownian motions of lignin molecules. This study suggests that both the HTD and the LTD methods
restrict the micro-Brownian motion of lignin molecules somewhat by the cross-linking of chains due to their heating history.
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Translated from Journal of Beijing Forestry University, 2008, 30(3): 96–100 [译自: 北京林业大学学报] 相似文献
7.
木材/蒙脱土(MMT)纳米插层复合材料的制备构想 总被引：11，自引：0，他引：11
基于聚合物 蒙脱土纳米插层复合材料的研究成果 ,综述了插层复合方法的原理、工艺过程和产品性能 ,分析比较了单体插层原位聚合和聚合物直接插层等方法。从木材与蒙脱土的结构和组成特性出发 ,分析比较了木材与聚合物溶解、熔融性的不同 ,讨论了利用插层复合原理制备木材 蒙脱土纳米复合材料的基本构想 ,并进一步提出了相应的技术路线和工艺流程概念图。 相似文献
8.
The structures of the solid state products formed by the partial combustion of Korean pine wood treated with fire-retardant
FRW were analyzed by microscopic FTIR. The volatile pyrolytic products of basswood (Tilia amurensis) specimens treated with FRW and its components guanylurea phosphate and boric acid were analyzed by GC-FTIR. The pyrolytic
and charring process, the effects of fire-retardant, and the structural characteristics of the pyrolytic products were discussed.
It was concluded that upon heating and by the catalysis of FRW and its decomposition products reactions of wood took place
successively, namely the dehydration of polysaccharide, the elimination of acetic acid from hemicellulose, the degradation
of polysaccharide, the degradation of lignin, the polymerization of the pyrolytic products of wood, reactions of oxygen-element-elimination
of aliphatic polymers and the structural change of the latter to form aromatic structures, and charring. The pyrolysis process
of wood was altered and the yield of volatile pyrolytic products was decreased by FRW treatment.
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Translated from Scientia Silvae Sinicae, 2005, 41(4): 149–154 [译自: 林业科学, 2005, 41(4): 149–154] 相似文献
9.
Cao Jin-zhen Yu Li-li You Xiao-di Kamdem D. Pascal 《中国林学(英文版)》2007,9(4):239-245
In order to clarify the interaction between copper and wood substances in wood treated with copper containing water-borne wood preservatives, the dielectric constant ε′ and dielectric loss factor ε″ of untreated wood and wood treated with four concentration levels of copper-ethanolamine (Cu-EA) solutions were determined within a temperature range from –100 to 40°C and a frequency range from 100 to 1 MHz. Three dielectric relaxation processes were observed in the ε″ spectrum; among them R-I is based on the reorientation of methylol groups in the amorphous region of wood cell walls and R-II is related to wood extractives. R-III appeared in Cu-EA treated wood, and its magnitude decreases with the concentration of Cu-EA solutions used in this experiment. This relaxation process was considered to be based on the reorientation of copper-ethanolamine-wood complexes in wood cell walls. At low copper retention, the hydrogen in the complex can form hydrogen bonding with adjacent hydroxyl groups, which results in a strong bonding state between copper and wood; at high copper retention, the numerous copper-ethanolamine complexes not only hinder them from forming hydrogen bonding with adjacent wood molecules due to steric hindrance, but also weaken the interaction between wood molecules themselves, which corresponds to reducing ε″ values of both R-I and R-III processes. The results explain the fact of in-creasing copper leaching in wood treated with high concentration copper-based water-borne preservatives. 相似文献
10.
For a better understanding of the binding between silicon dioxide and wood as well as the dielectric properties of silicon
dioxide/wood composite, dielectric relaxation was measured for untreated wood [Cunninghamia lanceolata (Lamb.) Hook] and for silicon dioxide/wood composite with different weight percentage gain (WPG). Cole–Cole’s circular arc
law, distribution spectrum of relaxation time and relation model were applied to the results of relaxation due to motions
of the methylol groups. The results were as follows. The generalized relaxation time and ε
s
− ε
∞
decreased with increasing WPG. The distribution spectrum of relaxation time decreased more and more and broadened with increasing
WPG. The methylol group in the amorphous region of the wood cell wall participated in hydrolysis reaction and condensation
reaction caused by tetraethylorthosilicate (TEOS), and there is a cross-link between silicon dioxide and wood. The value of
apparent activation energy (ΔE) increased for silicon dioxide/wood composite, and increased with increasing WPG. Activation enthalpy (ΔH) and activation entropy (ΔS) increased, while activation free energy (ΔG) decreased with increasing WPG. The number of hydroxyl groups cut in dielectric relaxation increased with increasing WPG. 相似文献
11.
The nano intercalation compounding of wood and MMT has important implications for the modification of wood and for the development of new materials. With water-soluble phenol formaldehyde resin as an intermediary, the nanocomposites of Chinese fir (Cunninghamia lanceolata) wood and montmorillonite (MMT) were prepared via three impregnation methods, i.e. normal pres-sure, once and twice vacuum methods. Based on the weight percent gain (WPG) of impregnated wood, the effects of compounding wood and MMT in term... 相似文献
12.
The interactions between pine wood nematode and three bacterium strains isolated from the nematode, Bursaphelenchus xylophilus, which are two strong pathogenic bacterium strains, Pseudomonas fluorescens GcM5-1A and Pseudomonas putida ZpB1-2A and a weak-pathogenic bacterium strain, Pantoea sp. ZM2C, were studied. The result showed that the strong-pathogenic GcM5-1A strain and ZpB1-2A strain significantly increased
fecundity, reproduction rate, and the body volume of the adult nematode. Meanwhile, pine wood nematodes significantly promoted
reproduction of the two strong-pathogenic bacterium strains. However, the weak-pathogenic bacterium strain, ZM2C, completely
inhibited reproduction of pine wood nematodes. Aseptic pine wood nematodes significantly inhibited reproduction of the strain
ZM2C. The results indicated that mutualistic symbiosis exists between pine wood nematodes and the two pathogenic bacteria
it carries. The phenomenon showed that the pathogenic bacteria carried by the nematode were not accidentally contaminated,
but rather had existed as symbionts of the nematode with which it had coevoluted over a long period. The role of mutualistic
symbiosis in the process of pine wilt disease was also discussed.
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Translated from Journal of Nanjing Forestry University, 2005, 29(3): 1–4 [译自: 南京林业大学学报, 2005, 29(3): 1–4] 相似文献
13.
In this study, the contact angles of four different reference liquids (including distilled water, diiodomethane, formadide
and glycerol) formed on the surfaces of wood, treated with chromated copper arsenate (CCA) and two other emerging copper-based
water-borne systems (commercial names: NW and NS) were measured with sessile drop method. Based on the contact angle data,
the surface energy was obtained from the acid-base approach. The total surface energy consisted of Lifshiz-van der Waals parameter
and acid-base parameter. Results showed that the NW and CCA treatments made the wood surface more hydrophobic while the NS
treatment had the reverse effect on the wood surface mainly owing to the increased penetration of earlywood. By using three
liquids, diiodomethane, formamide and distilled water, the total surface energy obtained for untreated earlywood, untreated
latewood, CCA-treated earlywood, CCA-treated latewood, NW-treated earlywood, NW-treated latewood, NS-treated earlywood and
NS-treated latewood were 43.1, 44.5, 43.4, 45.1, 49.4, 40.6, 46.0 and 40.9 mJ/m2, respectively. The surface energy of CCA-treated wood was almost the same as untreated wood. After NW and NS treatments,
the surface energy of both earlywood and latewood changed a little. However, the change was not so obvious as to draw any
further conclusion concerning the influence of NW and NS treatments on the surface energy of wood.
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Translated from Journal of Beijing Forestry University, 2006, 28(4): 1–4 [译自: 北京林业大学学报] 相似文献
14.
Haili Qiao Chengming Tian Youqing Luo Jianhua Sun Xiaofeng Feng 《Frontiers of Forestry in China》2008,3(3):347-351
To better understand the distribution of soil microorganisms in Populus euphratica forests in Xinjiang, northwestern China, we studied and compared the populations and numbers of bacteria, fungi and actinomycetes
in the soil at four different age stages of natural P. euphratica forests, i.e., juvenile forests, middle-aged forests, over-mature forests and degraded forests. Results showed that there
were clear differences in the amount of microorganism biomass and composition rates across the four forest stages. Dominant
and special microorganisms were present in each of the four different soil layers. The vertical distribution showed that the
microorganism biomass decreased with increasing soil depth. The population of microorganisms was the lowest at 31–40 cm of
soil depth. The microorganisms consisted of bacteria, actinomycetes, as well as fungi. Bacteria were the chief component of
microorganisms and were widely distributed, but fungi were scarce in some soil layers. Aspergillus was the dominant genus among the 11 genera of fungi isolated from the soil in different age stages of P. euphratica forests.
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Translated from Journal of Beijing Forestry University, 2007, 29(5): 127–131 [译自: 北京林业大学学报] 相似文献
15.
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
16.
Guangjie Zhao Wensheng Luo T. Furuno Qiang Ren Erni Ma 《Frontiers of Forestry in China》2007,2(2):231-236
In order to investigate the pyrolytic characteristics of the burning residue of fire-retardant wood, a multifunctional fire-resistance
test oven aimed at simulating the course of a fire was used to burn fire-retardant wood and untreated wood. Samples at different
distances from the combustion surface were obtained and a thermogravimetric analysis (TG) was applied to test the prrolytic
process of the burning residue in an atmosphere of nitrogen. The results showed that: 1) there was little difference between
fire-retardant wood and its residue in the initial temperature of thermal degradation. The initial temperature of thermal
degradation of the combustion layer in untreated wood was higher than that in the no burning wood sample; 2) the temperature
of the flame retardant in fire-retardant wood was 200°C in the differential thermogravimetry (DTG). The peak belonging to
the flame retardant tended to dissipate during the time of burning; 3) for the burning residue of fire-retardant wood, the
peak belonging to hemicellulose near 230°C in the DTG disappeared and there was a gentle shoulder from 210 to 240°C; 4) the
temperature of the main peaks of the fire-retardant wood and its burning residue in DTG was 100°C lower than that of the untreated
wood and its burning residue. The rate of weight loss also decreased sharply; 5) the residual weight of fire-retardant wood
at 600°C clearly increased compared with that of untreated wood. Residual weight of the burning residue increased markedly
as the heating temperature increased when burning; 6) there was a considerable difference with respect to the thermal degradation
temperature of the no burning sample and the burning residue between fire-retardant wood and untreated wood.
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Translated from Journal of Beijing Forestry University, 2006, 28(3): 133–138 [译自: 北京林业大学学报] 相似文献
17.
Jiying Song Youqing Luo Juan Shi Xiaosu Yan Weiping Chen Ping Jiang 《Frontiers of Forestry in China》2006,1(4):460-463
In November 2003 and June 2004, the insect borers and their spatial distribution within Pinus massoniana were investigated in Zhoushan City, in East China’s Zhejiang Province, where pine wood nematode (Bursaphelenchus xylophilus) are typically found. The niche width, proportional similarity of niche and the niche overlap of dominant species of dying
trees were computed. Results show that five insect species infect and damage Pinus massoniana, which had been infected by pine wood nematodes, among which four are wood boring beetles and one termite. Species within
host trees vary from winter to summer and all the species have their own niche width, proportional similarity of niche and
the niche overlap. They can achieve competitive equilibrium and coexistence according to their biological characteristics
and life habits.
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Translated from Journal of Beijing Forestry University, 2005, 27(6): 108–111 [译自: 北京林业大学学报, 2005, 27(6): 108–111] 相似文献
18.
Dynamic properties of bamboo, Phyllostachys pubescens, with moisture content (MC) ranging from −130 to 130°C, were studied by dynamic mechanical analysis (DMA). The results showed
that the hygrothermal effect on dynamic mechanical properties was negative. The storage modulus decreases with increasing
temperature and MC, and glass transition temperature decreases with increasing MC. The glass transition temperature and tan
delta of bamboo were 30.5°C, 0.02 and 10.61°C, 0.04, when MC was 10% and 34%, respectively.
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Translated from Journal of Nanjing Forestry University (Natural Sciences Edition), 2006, 30(1): 65–68 [译自: 南京林业大学学报(自然科学版), 2006, 30(1): 65–68] 相似文献
19.
Régis Mendonça André Ferraz Othar Kordsachia Gerald Koch 《Wood Science and Technology》2004,38(7):567-575
Scanning UV-microspectrophotometry was used to investigate the topochemistry of lignin removal from pine wood (Pinus taeda and P. elliottii) chips during biopulping involving wood treatment with Ceriporiopsis subvermispora (Pilát) Gilbn. & Ryv. followed by alkaline sulfite/anthraquinone delignification. A delignification front starting from the lumen towards the compound middle lamella was clearly observed in micrographs recorded from individual cell wall layers of wood samples biotreated for 30 days. Lignin was removed without cell wall erosion. UV-micrographs of wood samples cooked for a short time (90 min pulping) showed that the S2 of biotreated samples are more homogeneously delignified compared to the S2 of the undecayed controls. Similarly, the compound middle lamella and cell corners are also more delignified in biotreated samples. On the other hand, UV-micrographs of samples cooked for a long time (150 min pulping at 170°C) showed that there are no significant differences in the contents of residual lignin retained in the S2 of undecayed and biotreated wood samples. 相似文献
20.
We have studied the structural mechanism of micron flaky wood fiber light density board (MFLB), of which voids are an important
structural characteristic. A new parameter called hole compressibility (η) was added to study the characteristics of MFLB
further, in order to produce various levels of hole compressibility. A set of hot pressures was applied, and uniform parts
at cross-sections of MFLB were selected to study the effects of hole compressibility on the modulus of elasticity (MOE) and
modulus of rupture (MOR) of MFLB by microscopic analyses. The results showed that MFLB (0.3 g/cm3 in density) processed at various hot pressures (from 1.6 to 2.2 MPa) all meet the norms of the Japan Light Particleboard
Industrial Standard JISA 5908, where η ⩽ 0 ranging from −0.0487 to −0.068. The critical value of hole compressibility at which
the strength began to decrease was also obtained. We compared the void distribution, size and shape at different void contents
and hole compressibility and discussed the effects of hole compressibility on MOE and MOR of MFLB as well. To a certain density
of raw material and micro-fiber of a certain thickness, the strength of MFLB can be decreased with an increase in hole compressibility.
When the hole compressibility of MLFB exceeds a certain critical value, loading at a lower level will decrease MOR and MOE
of MFLB considerably.
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Translated from Scientia Silvae Sinicae, 2007, 43(6): 123–127 [译自: 林业科学] 相似文献