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1.
利用松香对腰果酚改性后制备漆膜,考察了松香用量对腰果酚固化过程的影响,并对漆膜性能进行了研究。通过红外光谱法(FT-IR)分析松香改性腰果酚的固化机理及松香用量对漆膜固化速率的影响。实验结果表明：加热过程中腰果酚的酚羟基与松香的羧基发生酯化反应,松香树脂酸的不饱和结构以及腰果酚不饱和侧链发生氧化交联反应。随着松香用量的增加,腰果酚的固化速率增加,松香用量(以腰果酚质量计)为10%,在5%环烷酸钴催化下,150℃固化24 h能得到高光泽度的综合性能较佳的生物基松香改性腰果酚漆膜,其光泽度为115,附着力为1级,铅笔硬度为2H,冲击强度为35 kg/cm,柔韧性为1 mm。 相似文献
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以腰果酚为原料,通过合成腰果酚酚醛树脂,进而合成腰果酚酚醛环氧树脂(Epoxy-Ⅰ)和高环氧值的腰果酚酚醛环氧树脂(Epoxy-Ⅱ),探讨了各阶段的反应条件。其中腰果酚酚醛树脂合成的最佳条件为:催化剂乙酸锌用量为腰果酚质量的3%,在90℃下反应3 h;Epoxy-I合成的最佳条件为:苄基三乙基氯化铵(BTEAC)催化剂用量为2%,在90℃下醚化反应4 h;当环氧化剂用量为Epoxy-Ⅰ质量的80%,在70℃反应6 h可制备出高环氧值的Epoxy-Ⅱ。采用傅里叶红外光谱和核磁共振光谱表征了两种目标环氧树脂的化学结构。 相似文献
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以腰果壳液中提取的腰果酚(Cardanol)为主要原料,合成了六种新的钛酸酯偶联剂。由反应的出醇率得出合成反应的酯交换率均在88.0～97.5％之间,删定了产物的分子量及元素钛含量;产物的紫外光谱在200nm以上的两个吸收峰与原料腰果酚对比后的位移,以及红外光谱对比原料后,在3370～3t00cm~(-1)附近OH基强吸收峰基本消失,2800cm~(-1)附近羧基中OH基伸缩振动吸收峰的消失,1650～1800cm~(-1)区羧基中C=O基伸缩振动吸收峰的消失等现象都证明了产物的结构。这类偶联剂由于含有腰果酚的苯环和侧链上的多个双键,是一类反应活性高,应用性能较为特殊的偶联剂。它们可在水中直接乳化做为乳化剂,能大幅度降低无机—有机复合体系的粘度,应用于填充聚氯乙烯塑料,可明显改善加工性能和制品的物理机械性能,并能提高无机填料的填充量,降低生产成本。 相似文献
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以腰果酚、六氯环三磷腈(HCCP)为原料,利用NaH作为缚酸剂制备了膦腈环核六取代腰果酚(HCPP),并采用H_2O_2/HCOOH体系对HCPP进行环氧化反应得到膦腈环核腰果酚环氧树脂(EHCPP),实验优化了EHCPP的合成条件,并采用FT-IR和~1H NMR对中间产物HCPP和最终产物EHCPP进行了分析和表征。实验结果表明:EHCPP较佳合成条件为以腰果酚的双键为基准,n(双键)∶n(甲酸)=1.0∶1.0,n(双键)∶n(H_2O_2)=1.0∶1.8,催化剂TsOH添加量为1%(以HCPP质量为基准),反应温度65℃,反应时间6 h;此条件下得到的产物EHCPP环氧值为4.1 mmol/g。FT-IR和~1H NMR分析结果表明:实验得到的HCPP和EHCPP的结构与预期结构基本相符。 相似文献
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以天然腰果酚为原料制备了一种高活性腰果酚基环氧稀释剂(CDE),利用所制备的CDE与双酚A型环氧树脂(E-51)共混,再与甲基四氢苯酐进行交联固化反应,通过力学性能测试,研究了稀释剂含量对固化物性能的影响。实验结果表明:CDE对E-51有显著的稀释增韧作用;随着CDE含量的增加,固化树脂的玻璃化转变温度逐渐降低;当CDE的加入量为20%时,固化物的冲击强度及拉伸强度达到最大值,分别为19.17 k J/m2和56.81 MPa,弯曲强度为108.8 MPa。 相似文献
8.
腰果壳液的蒸馏及其馏分的色-质谱联用分析 总被引：8，自引：0，他引：8
用蒸馏法从商品腰果壳液中提取主成分腰果酚。采用色谱-质谱-计算机联用仪对蒸馏馏分进行定性和半定量分析。结果表明,常压或减压蒸馏均能得到腰果壳液的主成分。减压蒸馏可大大提高馏分的得率,在真空度1999.832Pa进行减压蒸馏时,最高得率为72％;得率约60％时,其残留物尚能得以利用。蒸馏馏分为淡黄色油状液体,其中含有约75％的腰果酚、10％其它酚类化合物和15％的烷基苯;其颜色比原腰果壳液浅得多。该主馏分腰果酚带有饱和(10％)、单烯(59.9％)、双烯(17.7％)和三烯(12.5％)的长侧碳链,其总不饱和度比原腰果壳液主成分低。 相似文献
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腰果酚光固化材料的研究进展 总被引：1，自引：0，他引：1
《林产化学与工业》2018,(6)
光固化涂料具有固化速度快、节能环保等优势,在诸多领域得到应用。天然腰果酚可替代石油基酚类化合物广泛应用于涂料、胶黏剂、聚合物材料等领域。腰果酚含有酚羟基和侧链不饱和双键,具有较高的反应活性,可通过化学改性应用于光固化涂料。简单介绍了腰果酚的来源及分子结构,从腰果酚直接紫外光固化、酚羟基改性(酯化和醚化)、侧链改性及复合改性等角度,综述了近年来国内外有关腰果酚光固化材料的研究和应用进展,并展望了腰果酚光固化材料未来研究的热点。 相似文献
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腰果酚(CD)和1,3-二溴丙烷经Williamson醚化反应得到一种腰果酚二醚化合物(CDE),然后以CDE、多聚甲醛和二乙烯三胺为原料,经Mannich反应制备得到一种浅色的腰果酚二醚曼尼希碱固化剂(MBCDE)。通过傅里叶红外光谱(FT-IR)和核磁共振氢谱(~1H NMR)表征了产物的化学结构,并与氨乙基哌嗪(AEP)进行对比研究其相关性能。通过热重分析(TGA)、扫描电镜(SEM)和力学性能测试研究了两种固化剂与双酚A环氧树脂(DGEBA)固化材料的相关性能。结果表明:MBCDE/DGEBA的最大分解温度为351.6℃,具有良好的热稳定性。AEP/DGEBA环氧固化物的冲击强度为3.641 J/m,而添加80%的MBCDE后固化物的冲击强度则为5.155 J/m,提高了41.6%。SEM分析结果表明MBCDE固化材料中存在相分离。 相似文献
11.
《Forest Policy and Economics》2006,8(6):877-890
In this paper, circumstances where various human activities and interests clash with the conservation of forest biodiversity are examined, with particular focus on the drivers behind the conflicts. After identifying past and current human-related threats potentially leading to conflicts in forests, the paper will focus on conflict management and monitoring, with an emphasis on inclusionary stakeholder networks and a range of approaches towards sustainable land use. Three dimensions of conflicts are examined: substance (‘how things are’), procedure (‘how things are done’), and relationships (‘how people behave’). These relations will relate to three conflict management approaches: (1) technical, which may contribute to reduce or solve the conflict acting on the ‘substance’ dimension, (2) political, which may influence the ‘procedure’ dimension of the conflict establishing principles or rules, and (3) cultural, which may affect the ‘relationship’ dimension of the conflict. Finally, a general model of adaptive conflict management emphasising communication among the parties and a participatory approach that involves monitoring of the conflict resolution outcomes is proposed. The recognition that strong perceptions among stakeholders have the potential to aggravate conflicts is central to the concept of a inclusionary conflict management framework, improved communication between all stakeholders, and better awareness of the context of the conflicts is emphasised. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):234-240
Proanthocyanidins (PAs), which are common phenolic compounds in plants, are considered to be mainly defensive compounds against different kinds of stress, e.g. herbivory. In addition to increasing after stress, they may condense and/or oxidize to form coloured compounds when cells die, which may affect both the resistance of xylem to rot and its colour. This is important in the mechanical wood industry. The effects of some biological factors (growing site, sampling date, wood location in the trunk) on the concentration of soluble PAs (sPAs) were studied in fresh and dried birch wood. Those factors that affected sPA concentration most were sampling date and radial location. Drying method also had a great effect on the sPA concentration, which in turn correlated with the colour of the wood. 相似文献
13.
Matteo Patergnani Lapo Mughini Gras Giovanni Poglayen Aldo Gelli Fernando Pasqualucci Marco Farina Laura Stancampiano 《Journal of pest science》2010,83(3):347-359
Anticoagulant poisoning is a common rodent control method in urban areas, but rodents may exhibit versatile feeding behavioural
habits in varying environmental conditions. This study has been conducted to determine those environmental factors that could
directly influence bait consumption and which therefore may affect an urban rodent control plan carried out with chemical
methods. In the city of Bologna (Italy), 2500 bait stations have been monitored in various urban biotopes and the bait consumption
studied in relation to several environmental factors, using both bivariate and multivariate analysis. Results reveal that
the rodent patch distribution triggers the avoidance of baits placed outside of their home-range, hence the importance on
bait placement. The logistic regression model confirms that vegetation, harbourage and water supplies are important variables
in determining bait consumption, probably because they may spatially and temporarily facilitate the agoraphobic rodent movement,
ensuring undisturbed bait consumption. The role of predators (dogs and cats) and food competitors (synanthropic birds) remains
insignificant. However, bait eating invertebrates may consume part of the bait. For a proper rodent control plan the first
real need is to minimize the alternative food sources, which may compete with baits. Weather conditions in which rodents could
possibly pass unnoticed (fog and rainfall) may encourage bait consumption, vice versa with a cold climate. The considered
environmental factors have satisfactorily explained bait consumption, highlighting the importance of human influence. The
study of environmental factors may be useful in categorizing several site-specific conditions where rodent control efforts
should be targeted, enhancing any intervention by matching the correct and specific strategy. 相似文献
14.
Consulting forester business practices are challenged by significant decreases in the sizes of private forest properties and the changes in landowner values that accompany forestland parcelization. Though researchers have discussed the potential ways entrepreneurial foresters could adapt to these new ownership patterns and landscape dynamics, actual responses by foresters working in parcelizing landscapes are largely undocumented. We conducted twenty in-depth interviews with foresters working in New York State to determine (1) how foresters have experienced parcelization of properties they work with, (2) what challenges are associated with forestry projects on decreasing property sizes, and (3) what kinds of changes foresters are making to adapt to decreasing property sizes. We found that foresters across the state observe decreasing sizes of forest properties and see values of forest owners shifting beyond timber production, although most do not consider these changes to be the most urgent challenges to sustainable forestry and profitable forest consulting. Professional foresters are reacting to parcelization in diverse ways; while some are trying entrepreneurial approaches to reach new clients or offer different services, others are primarily interested in maintaining their traditional practices and roles. These findings indicate that strictly relying on independent entrepreneurial responses by private foresters may not be sufficient to close the gap between the historical role of consulting foresters and the trajectory of modern forest parcels. Additional measures like specialized training and policy changes may also be required to address the management challenges associated with forestland parcelization. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(6):555-573
Nitrogen (N) is the only nutrient that promotes forest growth when given individually. An extra stem growth of 15 m 3 ha -1 is obtained during a 10 yr period following an application of 150 kg N ha -1 . Larger growth increases have often been the result of more intensive N fertilization. Lime or wood ash give a minor growth stimulation on sites with a carbon (C) to N ratio below 30 in the humus layer, while the opposite effect prevails on N-poor sites. Nutrients given as soluble fertilizers are readily taken up by trees. Boron deficiency may be induced in northern Sweden after N fertilization or liming. The ground vegetation may be altered by single-shot N fertilization, but long-term effects occur only for intensive regimes. Lime or wood ash may modify the flora if soil pH is significantly altered: the change will be in response to N availability. Fruit-body production of mycorrhizal fungi is disfavoured by chronic N input, but also by lime or ash. However, the mycorrhizal structures on root tips are less affected. Faunistic studies are not common and those present are mostly devoted to soil fauna. A practical N dose of 150 kg N ha -1 has no clear effect, but higher doses may reduce the abundance in some groups. Hardened wood ash does not significantly affect the soil fauna. Lime favours snails and earthworms, while other groups are often disfavoured. The response of aquatic fauna to terrestrial treatments has hardly been studied. N fertilization generally results in insignificant effects on fish and benthic fauna. Lime and wood ash reduce the acidity of the topsoil, but practical doses (2-3 t ha -1 ) are too low to raise the alkalinity of runoff unless outflow areas are treated. N fertilizer use in forestry and N-free fertilizers lack effects on acidification. N fertilization may, however, be strongly acidifying if nitrification is induced and followed by nitrate leaching. N fertilization often results in increased long-term C retention in trees and soil, but does not promote significant N 2 O losses. N may temporarily reduce CH 4 oxidation in soil, but there are indications of a long-term opposite effect. Lime and poorly hardened wood ash may cause losses of C from N-rich soils. Only a few per cent of added N are leached to surface water following practical N fertilization, while N-free fertilizers do not induce N leaching. Soil incubations and soil-water studies suggest an increased risk for nitrate formation and leaching where lime or wood have been added to N-rich soils, but increased leaching to surface water has not been observed. Wood ash causes a temporal increase in bioavailability of cadmium (Cd). Other fertilizers may indirectly increase the availability of heavy metals. Wood ash may contain radioactive caesium 137Cs, but addition of such ash does not increase radioactivity in plants and soil. 相似文献
16.
Water and nutrient dynamics and tree growth 总被引：1，自引：0，他引：1
The balance in the investment of assimilate at any time into leaves and roots may depend on whether water, nutrients or radiation are limiting to growth. Also, for the same investment of assimilate into roots, the root configuration may range from intensive to extensive in both space and time, to take best advantage of the distribution and amount of water and nutrients. Intensive root configurations, which include mycorrhizas and proteoid roots, assist in the uptake of nutrients (such as phosphorus) which are rate-limiting in soil. Mycorrhizas may assist in water uptake in dry or coarse textured soils with low unsaturated hydraulic conductivities.
Adaptations which assist trees to survive in dry and nutrient-deficient environments are discussed. These mechanisms may reduce, maintain or increase growth. In production forestry, it is desirable to exploit those mechanisms which increase growth. When soil water and nutrients limit tree growth, productivity may be improved by increasing the amount of uptake of water and nutrients, or by increasing the efficiency by which they are used in growth. Maximizing water-use efficiency when soil water supply is limiting may be dependent on whether the trees are in mixed stands or in monoculture. Selecting trees with relatively less root may improve productivity in monocultures when weeds are controlled and fertilizer is added. It is well known that trees can ‘re-use’ nutrients by retranslocating them within the tree to zones of demand. Relatively little is known, though, about differences in the biochemical involvement of nutrients at the cellular and subcellular level which contribute to differences in nutrient-use efficiency in trees. 相似文献
17.
Latitudinal shifts in tree species distributions are a potential impact of climate change on forest ecosystems. It has been hypothesized that some tree species may become extirpated as climate change effects may exceed their migration ability. The goal of this study was to compare tree species compositions in northern urban areas to tree compositions in forestland areas in the eastern U.S. as an indicator of the potential for urban trees to facilitate future forest tree species migration. Results indicated that a number of tree species native to eastern U.S. forests of southern latitudes are currently present in northern urban forests. The biomass density (Mg/ha) of urban tree species is typically less than half of forestland densities with the majority of urban tree species found in nearby (<100 km) forestland. Urban tree propagation is often facilitated by humans, whereas the necessary pollinators and agents of tree seed dispersal in forestlands may be lacking regardless of climate change. It is suggested that urban areas may serve divergent, dual roles as both a native tree seed source and refuge for a limited number of forestland tree species, but also a facilitator of non-native tree invasion. 相似文献
18.
Identifying, managing and monitoring conflicts between forest biodiversity conservation and other human interests in Europe 总被引：3，自引：0，他引：3
Jari Niemel Juliette Young Didier Alard Miren Askasibar Klaus Henle Richard Johnson Mikko Kurttila Tor-Bjrn Larsson Simone Matouch Peter Nowicki Rosa Paiva Luigi Portoghesi Ren Smulders Alan Stevenson Urmas Tartes Allan Watt 《Forest Policy and Economics》2005,7(6):877-890
In this paper, circumstances where various human activities and interests clash with the conservation of forest biodiversity are examined, with particular focus on the drivers behind the conflicts. After identifying past and current human-related threats potentially leading to conflicts in forests, the paper will focus on conflict management and monitoring, with an emphasis on inclusionary stakeholder networks and a range of approaches towards sustainable land use. Three dimensions of conflicts are examined: substance (‘how things are’), procedure (‘how things are done’), and relationships (‘how people behave’). These relations will relate to three conflict management approaches: (1) technical, which may contribute to reduce or solve the conflict acting on the ‘substance’ dimension, (2) political, which may influence the ‘procedure’ dimension of the conflict establishing principles or rules, and (3) cultural, which may affect the ‘relationship’ dimension of the conflict. Finally, a general model of adaptive conflict management emphasising communication among the parties and a participatory approach that involves monitoring of the conflict resolution outcomes is proposed. The recognition that strong perceptions among stakeholders have the potential to aggravate conflicts is central to the concept of a inclusionary conflict management framework, improved communication between all stakeholders, and better awareness of the context of the conflicts is emphasised. 相似文献
19.
世界木材制浆技术新进展 总被引：1，自引：0，他引：1
文章论述了木材制浆技术的新进展，在硫酸盐法制浆技术的革新方面，推荐了间歇蒸煮的快速置换加热（ＲＤＨ）技术与连续蒸煮的改良连续蒸煮（ＭＣＣ）和深度脱木素改良连续蒸煮（ＥＭＣＣ）技术。还介绍了超高得率制浆方法，特别是碱性过氧化氢机械制浆（ＡＰＭＰ）法和爆破制浆（ＥＰ）法，用这两种方法生产的纸浆得率高、白度高、强度高、能耗较低。 相似文献
20.
Plant functional groups based on vegetative and reproductive traits in a subtropical forest community 总被引：1，自引：0，他引：1
Plant functional types (PFTs) are essential for us to research on community structure and dynamics. A proper criterion for assessing PFTs in a broad-leaved community is yet to be established, and the reports for correlations between PFTs and plant succession are still rare. The current study aimed to: (1) detect which functional trait(s) of woody species would best characterize PFTs in a forest community, and (2) explore general trends of functional traits with plant succession. We sampled fruit-bearing twigs of 55 woody species in a subtropical forest in southwest China, and recorded two sets of sizes of functional traits including both vegetative and reproductive organs. A principal components analysis (PCA) was performed on the functional traits studied, and the functional types were grouped out with K-means clustering. Next, the relationship between PFTs and species succession status was examined. The PCA revealed that of all the functional traits studied, twig sizes may exert a greatest impact on the traits assemblages and PFTs’ performances in this community, i.e., twig size may act as an important determinant for PFTs at the species level. The 55 woody species were classified into three distinct PFTs whose sizes tended to increase with the advance of species succession. Twig size tended to combine with leaf size, and so was the fruit size with seed size. 相似文献