CaCO_3与滑石粉协同改性对水性UV固化木器涂料性能的影响

采用CaCO_3和滑石粉协同改性对水性紫外光(UV)固化木器涂料进行改性,通过优化工艺参数制备了水性UV固化木器涂层。对水性UV固化木器涂层的力学性能(硬度、附着力和耐冲击强度)和光泽度进行了测试。发现当CaCO_3含量为1.0%,滑石粉含量在2.0%左右,在40℃烘箱中干燥10min,UV灯辐射1min,UV灯为2盏时,水性UV固化木器涂层具有良好的硬度、附着力和冲击强度,但是当滑石粉含量高于2.0%时水性UV固化木器涂层的力学性能反而下降。光泽度结果表明,水性UV固化涂层的光泽度随滑石粉含量的升高而下降。当CaCO_3含量为1.0%,滑石粉含量大于5.0%时,水性UV固化木器涂层光泽度呈现亚光。     

硅溶胶含量对UV固化水性木器涂料漆膜质量的影响

采用硅溶胶对UV固化水性木器涂料进行改性,并对改性后的UV固化水性木器涂料涂层的力学性能(耐磨性、硬度、附着力和抗冲击性能)和光学性能进行测试,旨在通过改性改善UV固化水性木器涂料漆膜的力学性能和光学性能,满足市场对水性绿色涂料的需求。试验结果表明:当硅溶胶的含量为1%(质量分数),紫外灯为3盏,干燥时间为20 min时,UV固化水性木器涂料漆膜的力学性能达到最佳,其耐磨性、硬度、附着力和抗冲击强度分别达到0106 g、H级、3级和90 kg·cm,但是当硅溶胶的含量大于1%时,漆膜的耐磨性、硬度、附着力、抗冲击性反而下降;光泽度的测试结果表明,涂层的光泽度随着硅溶胶含量的升高而下降,当硅溶胶含量为2%~6%时,涂层呈现亚光光泽度。该改性工艺步骤简洁、条件可控、价格低廉,且能满足日常生活中对UV固化水性木器涂料的需求。     

协同改性对水性UV木器涂料性能的影响

采用SiO2和CaCO3对水性紫外光(UV)固化木器涂料进行协同改性,通过优化工艺参数制备了水性UV固化木器涂层,并对涂层的力学性能和光泽度进行了测试.发现当水性UV固化木器涂料中CaCO3的含量控制在5.0％,SiO2含量在2.0％ ～3.0％时,先将水性UV固化木器涂料在40℃烘箱中干燥10 min,然后在UV灯下照射1min,得到的水性UV固化木器涂层具有良好的硬度、附着力和抗冲击强度;但是当SiO2含量高于3.0％时,水性UV固化木器涂层的力学性能反而下降.光泽度测试表明,当CaCO3含量控制在5.0％,水性UV固化木器涂层的光泽度随SiO2含量的升高而下降,当SiO2含量超过1.0％时,水性UV固化木器涂层呈现亚光光泽度.     

纤维素纳米晶体/KH560对UV固化水性木器涂层性能的影响

随着人们环保意识的提高,对于木器产品所用涂料的要求也更加严格,安全环保的水性涂料在木器行业的应用将成为趋势。笔者围绕水性UV固化木器涂料展开研究,采用高强度高表面能的纤维素纳米晶体(CNC)和高反应活性的硅烷偶联剂KH560对其进行改性,以求开发出涂层综合性能更优的水性UV固化木器涂料,为扩大水性UV固化木器涂料的产业化应用提供必要的理论依据。结果表明:CNC和KH560对水性UV固化木器涂层的力学性能和光学性能均有影响,经CNC协同硅烷偶联剂改性的水性UV固化木器涂层的耐磨性得到明显提升,同时涂层的抗冲击性、硬度、附着力等也得到改善,光泽度趋向亚光且可调。该方法成本低廉、过程可控、适用性好且能够满足日常对水性UV固化涂料的使用需求。     

纳米碳化硼对水性聚氨酯木器涂料性能的影响

围绕水性聚氨酯木器涂料(WPU),以纳米碳化硼(B_4C)为改性剂,采用物理共混的方法制备改性水性聚氨酯木器涂料,利用磁力搅拌和超声处理的方式提高B_4C的分散性,从而改善WPU的硬度、耐磨性和附着力等,通过扫描电子显微镜(SEM)观察不同添加量下纳米B_4C在涂层中的分散性。结果表明:纳米B_4C的添加显著增强了固化后水性聚氨酯涂层的硬度、耐磨性和附着力,但光泽度和涂料黏度有所下降。当B_4C添加量为3%时,涂层表面B_4C分散均匀,漆膜表面没有产生明显粗糙感,没有明显团聚现象产生;改性水性聚氨酯的涂层力学性能达到最佳,涂层硬度由2H提高至4H;涂层耐磨性与未改性涂层相比明显提高,磨耗量降低50%,最佳磨耗量为0.042 g;涂层附着力没有明显变化,在B_4C各添加量配比下均保持1级;涂层的光泽度随着B_4C的添加逐渐降低,由18.6%变为8.3%。碳化硼改性水性聚氨酯涂料的制备原理简单、实验过程易操作且绿色无污染,为纳米改性功能型水性涂料的制备提供了新的有效途径。     

紫外光固化桐油基水性聚氨酯木器涂料的制备

紫外光(UV)固化木器涂料具有环保、节能、高效等特点,近年来成为涂料行业的研究热点,是木器涂料领域的发展方向之一。为应对化石原料不断消耗及环境污染日益严重的现状,利用可再生且廉价的生物质材料制备紫外光固化木器涂料受到广泛关注。笔者通过改性桐油制备桐油基二元醇(TOP)来替代石油基多元醇,制备了一种可UV固化的桐油基水性聚氨酯(WPU)木器涂料。结果表明：当TOP添加量为42.5%(质量分数)时,薄膜力学性能最好,拉伸强度为(1.38±0.13)MPa,断裂伸长率为(179.32±4.05)%,弹性模量为(31.28±3.17) MPa,粒径为287.9 nm,水接触角为(75.89±0.91)°,耐水性较好;硬度、附着力、光泽度、粗糙度和漆膜磨损质量分别为4H、1级、10.24°、1.66μm和每100 r 0.003 g,所制备的WPU硬度、附着力及耐磨性分别满足GB/T 6739—2006《色漆和清漆铅笔法测定漆膜硬度》、GB/T 4893.4—2013《家具表面漆膜理化性能试验第4部分：附着力交叉切割测定法》及GB/T 4893.8—2013《家具表面漆膜理化性能试验第8部分：耐...     

硅烷偶联剂改性水性UV木器面漆性能研究

水性UV木器涂料是一种新型的水性涂料,它将传统涂料和UV固化涂料进行有机结合从而改善其性能。相比于传统的UV木器涂料,水性UV木器涂料具有抗划伤性、耐化学性和柔韧性等优点,所以得到较快发展,但水性UV木器涂料也有很多不足。笔者用改良剂硅烷偶联剂KH560对水性UV木器涂料面漆进行改性,通过实验测试力学、光学和颜色等各方面性能,为改良水性UV涂料木器提供参考依据。结果表明,将试验所用木质基材面漆的质量固定为1.5 g,KH560质量分数为3%,烘箱温度设置为40℃,干燥时间为10 min,UV灯的数量为3盏,辐射时间1 min时,涂膜硬度和附着力分别达到H和1级。涂膜在单瓣豆木质基板的综合效果较佳,同时产生亚光效果,色差最小。面漆中KH560的含量继续增加,涂膜的附着力不变,硬度先升高而后降低,光泽度上升,色差增大。     

脲醛树脂包覆氟树脂微胶囊制备及对木器表面涂层性能的影响

木器水性涂料因其安全环保特性逐渐替代传统溶剂型涂料,但其力学性能较差,在使用过程中易产生微裂纹,影响木器表面涂层的性能与使用寿命。通过微胶囊技术对木器水性涂料进行改良,包覆含有修复功能的芯材材料,可以实现木器表面涂层的自修复功能。氟树脂性能优良,并且可在常温下固化。本研究以脲醛树脂为壁材,氟树脂和水性涂料为芯材,通过原位聚合法制备了脲醛树脂包覆氟树脂微胶囊,并探讨了微胶囊对木器表面水性涂层光泽度、力学、色度及修复效果的影响。结果表明:微胶囊芯壁比为0.75时包覆效果最佳,微胶囊添加量(质量分数,下同)为1%时漆膜中颗粒物团聚现象最少,表面最光滑;漆膜光泽度随微胶囊添加量升高而降低;微胶囊的芯壁比和添加量对漆膜硬度和附着力影响较大,对抗冲击力影响不大;微胶囊芯壁比为0.65、添加量为4%～10%时对漆膜耐老化性能改善效果最显著。微胶囊芯壁比为0.65、添加量为7%时椴木表面水性面漆漆膜综合性能最佳,此研究为氟树脂微胶囊应用于木材表面水性涂层提供了技术基础。     

UV固化硅溶胶改性水性聚丙烯酸酯木器涂料的制备

用硅溶胶改性、紫外光固化构成的体系,弥补水性纯聚丙烯酸酯木器涂料力学性能不佳、硬度较低、固化速度较慢的缺陷。通过将具有环氧基团的KH-560硅溶胶引入带有活性羟基的水性聚丙烯酸酯乳液中,以提高水性聚丙烯酸酯膜的力学性能及附着力;进而通过调控功能性单体季戊四醇三丙烯酸酯(PETA)的添加量制得紫外光固化硅溶胶改性水性聚丙烯酸酯木器涂料。研究了不同水性聚丙烯酸酯乳液配方对漆膜、涂膜固化速度及性能的影响。结果表明:硅溶胶含量为10%、PETA含量为12%时,制备的硅溶胶改性水性聚丙烯酸酯分散体具有良好的贮存稳定性,且90 d内无沉淀分层现象,乳液有效粒径为250 nm,固含量达到44.98%,紫外光固化涂膜玻璃化转变温度为21.78℃,拉伸强度为21.98 MPa,断裂伸长率为31.5%,凝胶率为92.62%,漆膜紫外光固化时间10 s,硬度达到3H,附着力达到1级。与传统水性纯聚丙烯酸酯体系相比,紫外光固化硅溶胶改性聚丙烯酸酯体系制得的漆膜力学性能优异,硬度较高,固化速度明显提高。     

UV固化蓖麻油改性水性聚氨酯丙烯酸酯木器涂料的性能优化

利用多官能度活性稀释剂,将具有3个碳碳双键的季戊四醇三丙烯酸酯(PETA)引入到自乳化型紫外光(UV)固化蓖麻油改性的水性聚氨酯丙烯酸酯(WPUA)乳液中,增加体系的交联密度,以提高漆膜的力学性能、固化效率和硬度等,解决蓖麻油改性的WPUA木器涂料固化时间长、漆膜机械性能欠佳、乳液储存稳定性不良等缺点。研究表明:随着PETA添加量(质量分数)从2.3%增加至4.6%,水性聚氨酯丙烯酸酯乳液粒径变化范围为39.7～132.5 nm,乳液粒径分散指数(PDI)变化范围为0.072～0.289。随着PETA添加量的增加,涂膜质量损失率逐渐减小,而涂膜力学性能、硬度、耐水及耐化学品性能均逐渐增加。当PETA添加量为4.6%时,涂膜的拉伸强度最大为7.45 MPa,弹性模量最高为113.61 MPa,断裂伸长率最小为6.23%,涂膜硬度最高4H,光泽度最高为57.2,耐化学品、耐水性能最优;储存稳定性较佳,但是附着力由0级降至2级。因此,多官能度活性稀释剂PETA的引入对蓖麻油改性水性聚氨酯丙烯酸酯木器漆膜在力学性能、硬度、耐水及耐化学品等方面的性能优化可起到关键作用。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.