首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
研究了杉木(Cunninghamia laceolata)木粉不同粒度对羧甲基取代度及丙烯酸接枝高吸水树脂吸水率的影响规律。结果表明,100目和200目木粉与40目木粉X射线衍射峰没有区别,表明100目和200目木粉纤维结晶没有被破坏,木粉粒度对羧甲基取代度的影响不大;100目和200目木粉直接接枝丙烯酸聚合物吸水倍率明显降低,表明木粉颗粒逐渐变小,木粉原有的空间结构被破坏,不足以形成网络结构;红外光谱分析表明,杉木木粉羧甲基化后,纤维素和半纤维素中引进了大量的羧甲基,且保留了木质素特征峰,但在丙烯酸接枝的高吸水树脂中木质素吸收特征峰不存在,说明过硫酸钾引发剂产生的自由基优先与木质素苯环反应,使木质素苯环开裂,导致木质素苯环的吸收特征峰消失。  相似文献   

2.
杉木间伐材高温热处理后化学成分的变化   总被引:2,自引:1,他引:1  
以空气和菜子油为介质,分别用180,200和220℃处理杉木间伐材2和4 h,测定处理样综纤维素、纤维素、Klason木质素和苯醇抽出物相对含量的变化,并用傅里叶变换红外光谱分析高温热处理过程中木材内综纤维素的变化规律.结果表明:热处理后试材综纤维素含量均有不同程度的降低、纤维素总体降低较少,相应的苯醇抽出物含量、Klason木质素含量增加;温度升高、处理时间延长,木材主要化学组成的变化程度增大;在隔氧的油介质中进行热处理,试件的化学成分变化程度低于空气介质中热处理材;方差分析表明不同温度、时间、介质对主要化学组成产生极显著的影响;FTIR分析表明,180℃热处理时开始发生半纤维素分解,到200℃时纤维素也开始分解;氧气氛围对糖残基的热分解具有促进作用.在3 412,1 050,898 cm~(-1)附近相关糖残基,1 736 cm~(-1)附近相关C=O以及2 907 cm~(-1)附近对应C-H的吸收强度的变化也表征出热处理过程中各化学成分的变化规律.  相似文献   

3.
以阔叶材、针叶材、农业废弃物、灌木、果木五类木质资源为研究对象,从中选取桉木、落叶松等11种木质原料,使用傅里叶红外光谱(FTIR)对样本进行检测分析,并参照国家标准,分别对原料中综纤维素、α-纤维素、木质素、乙醇抽提物以及灰分含量进行测定,比较原料化学组成之间的差异。结果表明,11种木质原料的红外谱图,在3 329~3 343、2 892~2 924、1 417~1 423、1 367~1 372 cm~(-1)和1 730 cm~(-1)处,均出现了共同的振动吸收峰。阔叶材、农业废弃物、灌木和果木在1 230 cm~(-1)和835 cm~(-1)附近处出现表征紫丁香基木质素的振动吸收峰;针叶材在1 270 cm~(-1)处出现表征愈创木基木质素的振动吸收峰。阔叶材综纤维素、纤维素和半纤维素含量较高,杉木的木质素含量最高,为33.87%,柠条的乙醇抽提物含量最高,为9.91%,稻壳的灰分含量最高,为17.43%,这为原料及其化学成分的合理利用提供了理论依据。  相似文献   

4.
为了确定蜜环菌对榛子木材木质部和树皮部分的降解作用,以及对其成分的影响,本文对受蜜环菌降解不同时间的榛子木材的红外光谱进行研究。方法:选择蜜环菌作为侵染榛子木材的腐朽菌,以健康榛子木材和受蜜环菌腐朽40d、80d以及腐朽1年的榛子木材为研究材料,利用傅里叶变换红外光谱分析仪(FTIR)测定其红外光谱图。根据图谱中木质素、综纤维素及草酸钙官能团谱峰位置和谱峰相对吸收强度的振动变化情况,分析被蜜环菌腐朽后的榛子木材成分的变化情况。结果表明:榛子木材树皮部分和木质部中主要成分为木质素、综纤维素和一水草酸钙结晶(COM)。这3种成分均能被蜜环菌降解,并随着降解时间的改变,榛子木材成分发生不同程度的变化。其中,草酸钙可以被蜜环菌降解至含量很低,并能够在综纤维素降解时,再大量生成;另外,木质素的相关吸收峰,仅在受蜜环菌降解1年的榛子木材树皮部分发生变化,说明木质素很难被降解。  相似文献   

5.
采用GC-MS检测方法分别研究了20年生、30年生红心杉和普通杉木中边材及心材乙醇抽提物化学成分组成. 研究表明,醇提物中主要化学成分为:柏木脑和香紫苏醇. 醇提物中柏木脑百分含量范围:29.11%~52.54%,香紫苏醇百分含量范围:3.57%~24.77%. 红心杉和普通杉木心材中柏木脑含量均高于边材中柏木脑含量. 红心杉边材和心材中柏木脑含量均随着树龄的增加而增加,且柏木脑在木材中的横向分布,随树龄的增加呈同步增长趋势.红心杉和普通杉木,心材中香紫苏醇含量均高于边材中香紫苏醇含量.红心杉边材和心材中香紫苏醇含量均随树龄的增加而增加,且心材中香紫苏醇含量约为边材中含量5倍.  相似文献   

6.
东北常见树种木材形成早期组织波谱特征差异分析   总被引:1,自引:0,他引:1  
【目的】研究东北主要商品材树种木材形成早期组织的化学特征及其在树种间的差异,为揭示树木生长过程中木材细胞壁的自组装行为和木材形成的分子机制提供科学依据。【方法】选取东北10种重要商品材树种,采集木材形成早期组织,利用红外光谱和X射线衍射技术分析木材形成早期组织的波谱特征。【结果】红外光谱差别主要在波数900~2 000 cm~(-1)之间的指纹区域。针叶树种木材中波数1 735 cm~(-1)附近由木聚糖乙酰基C O伸缩振动引起的吸收峰相对强度显著小于阔叶树种木材。针叶树种木材中1511cm~(-1)处表征苯环碳骨架振动的吸收峰较明显,尤其是云杉和落叶松。针、阔叶树种木材在波数1 630~1 660 cm~(-1)之间均出现不同强度的吸收峰,峰形较宽,该峰归属为蛋白质肽段中氨基化合物振动引起。红外光谱二阶导数处理后,针叶树种木材在波数1 266 cm~(-1)处有明显吸收峰,阔叶树种木材中并未发现,该峰归属为愈创木基环加CO伸缩振动。而阔叶树种木材在1245cm~(-1)处有较明显吸收峰,该峰由木质素紫丁香基环振动引起。多数树种木材X射线衍射图谱I002有较强的衍射峰,但Iam的衍射峰并不明显,尤其是阔叶树种木材。因此推测木材形成早期组织中纤维素的晶型、晶胞或晶区大小与成熟木材不同。【结论】针、阔叶树种木材形成早期组织中木质素和半纤维素的沉积过程有所差别,这有助于揭示木材形成过程中化学成分和结构的变化规律。  相似文献   

7.
陈山红心杉木材化学成分的研究   总被引:10,自引:2,他引:8  
对不同树龄陈山红心杉和江西省不同产地普通杉木的木材化学成分进行了测定和比较,,分析了红心杉木材化学成分的特点,结果表明,:红心杉的红色物质与木质素,1%NaOH抽提物和苯醇抽提物有关。  相似文献   

8.
杉木和"三北"一号杨磨木木质素化学官能团特征的研究   总被引:23,自引:4,他引:23  
秦特夫 《林业科学》1999,35(3):69-75
本研究使用Bjrkman的提取方法,分离出针叶材杉木和阔叶材"三北"一号杨的磨木木质素(MWL),并采用Lundguist方法对分离出的MWL进行提纯.用红外光谱仪(FTIR)、超导核磁共振波谱仪(1HNMR)、液相色谱(HPLC)及紫外/可见分光光度仪(UV)测定了这两个树种MWL的化学结构和官能团.结果表明:(1)杉木木质素碳的含量较杨树高1.23%,氢和氧的含量分别低0.22%和0.85%,"三北"一号杨木质素中的甲氧基含量比杉木的高6.26%.(2)杉木和"三北"一号杨两种磨木木质素的苯基丙烷结构单元的经验式分别为C9H8.08O2.46(OCH3)0.94和C9H7.86O2.33(OCH3)1.41.(3)杉木磨木木质素中的脂肪族羟基(OHaliph)和酚羟基(OHph)数在每C9单元中分别是0.93和0.25,分别占总羟基的78.8%和21.2%."三北"一号杨磨木木质素中的脂肪族羟基(OHaliph)和酚羟基(OHph)数在每C9单元中分别是1.02和0.49,分别占总羟基的67.5%和32.5%.(4)杉木与"三北"一号杨磨木木质素在210nm附近的吸收波长基本相同.但在280nm附近杨树磨木木质素的吸收波长为280.2nm,而杉木磨木木质素由于愈疮木基丙烷产生了深色化效果,使吸收波长向长波长方向移动至282.2nm.(5)杉木的红外光谱吸收峰强度具有典型的针叶材特征,"三北"一号杨磨木木质素的红外光谱吸收峰强度与温带阔叶材的特征不完全吻合.(6)杉木和"三北"一号杨磨木木质素中每C9单元的β-O-4结构的平均质子数分别为0.33和0.50.β-5结构(苯基豆满香)中的平均H质子数量分别为0.23和0.16.β-β结构中Hα的平均质子数量分别为0.92和0.67.  相似文献   

9.
为研究树干倾斜角度对应压木木材细胞壁形成过程的影响,以7年生红松苗木为研究对象,对其茎干进行不同角度的倾斜处理.先后测定苗木的树高和胸径、木材形成组织中的木质素和纤维素含量、傅里叶红外变化光谱和极性代谢产物.结果表明:倾斜角度对高生长的抑制作用非常显著,对直径生长无显著影响.倾斜后木质素含量增加,纤维素含量降低;倾斜角度对木质素和纤维素含量均有显著影响.不同倾斜角度FTIR吸收峰强度也有明显差异.糖类、脂类、氨基酸、含氮化合物、有机酸等代谢物随倾斜角度呈现不同的变化规律.因此,红松苗木50°倾斜处理形成典型的应压木结构.代谢物相对含量的变化规律与形成的木材宏观性质相吻合.代谢物的变化也反映了树木对应力刺激的响应机制.  相似文献   

10.
杉木观光木混交林土壤腐殖质组成及特性   总被引:1,自引:0,他引:1  
1999年1月对福建三明莘口教学林场杉木观光木混交林及对照杉木纯林土壤腐殖质的有机碳和胡敏酸(HA)含量、HA/FA、可见光谱、红外光谱特性等进行研究。结果表明,与杉木纯林相比,混交林各土层土壤有机碳、胡敏酸含量及胡敏酸的E4值均有显著增加,HA/FA比值亦有所增加(不显著),而E4/E6值略有降低,胡敏酸红外光谱在1650 cm-1处出现明显的吸收峰。可见混交林中土壤腐殖质腐殖化程度和芳香度较纯林的高,这对土壤结构改良和有效养分供应有利,土壤肥力有一定程度的提高。图1表1参17。  相似文献   

11.
Summary A complete understanding of the processes underlying the transformation of sapwood into heartwood requires consideration of the chemical as well as other aspects of the change. A review of recent investigations into chemical topics is presented. There is a decrease in the storage materials from the outer and middle sapwood to the heartwood boundary, although there is one case where the reverse trend of sugar content was found and this may be a seasonal effect. The evidence presented shows that, in some species, some metabolic pathways operating at the sapwood-heartwood boundary differ from those in the sapwood. It is not known whether the reactions operating at the heartwood boundary include those previously operating in the sapwood or whether the new compounds are added to those already present. The composition of the heartwood extractives in a species is the same in different samles. Examples are given to show that the affected wood resulting from different forms of damage can be chemically different from normal heartwood. Consequently, the processes leading up to the death of the living cells can have a great influence on the composition of the extractives. Accordingly it is not only the constant composition of normal heartwood extractives that is under genetic control, but also the processes which initiate their formation. The intermediate zone and the factors which could initiate heartwood formation and control the amount of extractives formed, are considered. Evidence shows the extractives to be formed at the heartwood periphery from translocated carbohydrate, the amount of which is possibly under the control of growth-promoting hormones.
Zusammenfassung Zum Gesamtverständnis des Vorganges der Umwandlung von Splintholz in Kernholz müssen sowohl chemische als auch andere Gesichtspunkte in Betracht gezogen werden. Es wird zunächst ein Überblick über die neuesten Untersuchungen mit chemischen Zielsetzungen gegeben. Man findet vom äußeren und mittleren Splintholz gegen die Kernholzgrenze hin eine Abnahme der Inhaltsstoffe, obwohl es auch einen Fall gibt, wo es sich mit dem Zuckergehalt genau umgekehrt verhält, was auf eine jahreszeitliche Gegebenheit zurückzuführen sein dürfte. Die gewonnenen Erkenntnisse weisen darauf hin, daß bei einigen Holzarten die Art und Weise des Stoffwechsels in der Nähe der Splint-/Kernholzgrenze von demjenigen im reinen Splintholz wesentlich abweicht. Es ist bisher nicht bekannt, ob die Prozesse, die an der Kernholzgrenze ablaufen, auch diejenigen Prozesse einschließen, die zuvor im Splintholz stattfanden oder ob die neugebildeten Bestandteile einfach zu den schon vorhandenen hinzutreten. Die Zusammensetzung der Inhaltsstoffe des Kernholzes einer Holzart bleibt dieselbe innerhalb verschiedener Proben. Es werden Beispiele dafür aufgeführt, daß Holz mit Verletzungen, die das Ergebnis verschiedener Formen von Beschädigung sind, sich chemiseh vom normalen Kernholz unterscheidet. Infolgedessen kann der Vorgang, der schließlich zum Absterben lebender Zellen führt, einen beträchtlichen Einfluß auf die Zusammensetzung der Inhaltsstoffe haben. Es ist ferner nicht nur die konstante Zusammensetzung der normalen Kernholz-Inhaltsstoffe, die einer genetischen Steuerung unterliegt, sondern auch der Vorgang, durch welchen ihre Entstehung eingeleitet wird. Die Zwischenzone und jene Faktoren, welche die Kernholzbildung einleiten und die Menge der gebildeten Inhaltsstoffe steuern, werden erörtert. Das Ergebnis zeigt, daß die Inhaltsstoffe an der äußeren Hartholzgrenze aus umgelagerten Kohlenhydraten geformt werden. Ihre Menge wird möglicherweise von wuchsfördernden Hormonen gesteuert.


The paper was prepared for the Symposium Heartwood Formation and its Influence on Utilisation at the XIV. IUFRO Congress Section 41, Munich, September 1967.  相似文献   

12.
The inverse of the relative increment rate of size is proposed as a measure of the maturity of a forest tree. The heartwood content within bole cross sections is modeled semiempirically using asymptotic fitting. It is shown that the present proposal for a definition of maturity statistically explains heartwood content far better than age or size. The heartwood content appears to be independent on growth rate and tree size.  相似文献   

13.
Fractions of methanol and ethanol extracts from the heartwood of white cypress pine (Callitris glaucophylla Thompson et Johnson) were investigated for their repellent activity against subterranean termite Coptotermes formosanus Shiraki worker using a two-choice semicircular filter paper test at 0.5% (w/w) concentration. Fraction CY-E2 composed of (−)-citronellic acid, guaiol, α-, β-, and γ-eudesmol isomers as well as an unknown compound, showed the highest statistically significant repellency (97.8% ± 2.2 SEM) of all fractions tested. Bioactivity-guided fractionations using high-performance liquid chromatography led to the isolation of two, oxygenated eudesmane-type sesquiterpenes with α-methylene moieties, both termite-repellent compounds. These compounds were subsequently identified as ilicic acid methyl ester (IAME) and costic acid by means of spectroscopic analyses, electron impact mass spectrometry, and nuclear magnetic resonance spectroscopy. We report the isolation of both IAME and costic acid from C. glaucophylla heartwood for the first time. Part of this paper was presented at the 47th Symposium on the Chemistry of Terpenes, Essential Oils, and Aromatics, Tokyo, November 2003  相似文献   

14.
Antimicrobial activity of the heartwood of Taxus baccata   总被引:3,自引:0,他引:3  
The ethanolic extract of Taxus baccata heartwood showed significant activity against selected gram-negative bacteria and against five out of nine tested fungi.  相似文献   

15.
ABSTRACT

This paper describes the chemical composition of sapwood (SW) and heartwood (HW) of Pinus halepensis Mill stem. Extractives were first isolated by accelerated solvent extraction and then analysed by gas chromatography-mass spectrometry (GC-MS). The cellulosic polysaccharide content present in the pre-extracted wood samples was determined with acid hydrolysis and GC. The hemicelluloses content was determined with acid methanolysis and GC. Free monomers were additionally analysed by GC. The amount of lignin was determined gravimetrically by the Klason lignin method and the acid-soluble lignin was determined by a UV method. Formic and acetic acids in wood were determined after alkaline hydrolysis and analysed by HP-SEC. It was found that lipophilic and hydrophilic extractives were more abundant in heartwood (1.6% and 2.5%) than in sapwood (1.1% and 1.8%). Celluloses content was higher in sapwood (42.5%) than in heartwood (39.7%), whereas lignin, hemicelluloses and sugar monomer contents were more abundant in heartwood (28.9%, 26.8% and 0.3%) than in sapwood (28.0%, 24.5% and 0.2%). The variation in acetic and formic acids and ash contents between sapwood (0.7%, 0.2% and 0.5%) and heartwood (0.6%, 0.1% and 0.4%) was small. The acetylation degrees were found to be slightly similar in sapwood (0.4) and heartwood (0.3).  相似文献   

16.
In order to find new utilization method of woody wastes, we examined the bioactivities of extracts from branch heartwood of Chamaecyparis obtusa (hinoki) and compared to extracts from trunk heartwood. The bioactivities examined were antifungal activities against four fungi (Trametes versicolor, Fomitopsis palustris, Trichoderma virens, Rhizopus oryzae), and bioassay with brine shrimp (Artemia salina) which shows any allelopathic activities not measurable with fungi. Antifungal activities were observed in the hexane and ethyl acetate extracts of branch and trunk heartwood. The hexane and ethyl acetate extracts of branch and hexane extract of trunk showed strong lethality against brine shrimp. The yields of the active extracts of branch were much more than that of trunk. The identified compounds in the active extracts of branch were germacra-1-(10),5-dien-4??-ol, t-cadinol, t-muurolol, hinokiresinol, and hinokinin. Hinokiresinol and t-muurolol showed strong antifungal activities. Hinokiresinol showed bioactivities against T. virens, R. oryzae and brine shrimp. Germacra-1-(10),5-dien-4??-ol was lethal to brine shrimp. Germacra-1-(10),5-dien-4??-ol and hinokiresinol were minor components in trunk heartwood, but major components in branch. These qualitative and quantitative results suggest that the branch heartwood could be a valuable chemical resource because it contains large amounts of antifungal and allelopathic compounds.  相似文献   

17.
The aim of this work was to isolate a lectin from Myracrodruon urundeuva heartwood and to evaluate its antimicrobial activity against bacteria and fungi that attack plants, including woods. The lectin was isolated from heartwood through affinity chromatography on a chitin column monitored by hemagglutination assay. The lectin inhibited Gram-negative and Gram-positive bacteria and was more effective than antifungal Cercobin in growth inhibition of phytopathogenic fungi. The detected antimicrobial activity reveals the possible role of the lectin in the resistance of M. urundeuva heartwood against deteriorative biological agents. The M. urundeuva lectin is the first bioactive peptide found in heartwood, probably stored as a chemical protection against biodegradation.  相似文献   

18.
19.
J. Wilkes 《Forest Pathology》1983,13(4):215-218
Bacteria were not detected in clear or decaying heartwood from four eucalypt species. This may be associated with an observed intolerance of sapwood isolates to the highly acidic conditions and abundant extractives in the heartwoods.  相似文献   

20.
The purpose of this study was to compare the distribution of moisture contents (MCs) along the radial direction during radio-frequency/vacuum (RF/V) drying of log cross sections of heartwood (HLC) where sapwood was removed from a green log cross section and log cross section of mixed sapwood and heartwood (MLC) prepared with debarked logs of Japanese larch (Larix leptolepis) and locust (Robinia pseudoacacia). For Japanese larch, an even distribution of MC was observed over the entire cross section in HLC not only at the initial stage of drying but also up to the completion of drying. Furthermore, the moisture gradient between the outermost slice and the adjacent inner slice was more gradual compared with that in MLC. For locust, the moisture gradient between the outermost slice and the adjacent inner slice became severe as drying progressed. It decreased after reaching the maximum during the middle stage of drying but continued until the late stage of drying. Furthermore, despite the fact that the average initial MC of mixed slice within MLC was higher compared with that in heartwood slice, this trend reversed immediately after drying started. It was suggested that the possibility of formation of border checking would be high during drying the MLC, since it would be so complicate that the sapwood and heartwood reach fiber saturation point together because of differences in their green MCs and permeability between them.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号