蓖麻油聚氨酯丙烯酸酯复合乳液的研制

采用甲基丙烯酸甲酯(MMA)与蓖麻油水性聚氨酯共聚反应制备蓖麻油聚氨酯丙烯酸酯(CPUA)复合乳液,研究了蓖麻油添加量、MMA添加量和引发剂种类对合成CPUA复合乳液及涂膜性能的影响,并应用傅立叶红外光谱(FT-IR)测定反应产物的结构.研究发现随着蓖麻油和MMA添加量增大,CPUA复合乳液胶粒平均粒径增大,粘度减小,涂膜光泽度下降,机械性能和耐水性增强,确定了合适的蓖麻油和MMA含量,分别为体系总固体质量的20%～25%和20%～30%.采用偶氮二异丁腈(AIBN)和过硫酸钾(KPS)复合引发剂可提高单体的转化率;性能测试表明,本研究合成的CPUA复合乳液具有优异的物理机械性能和耐水性.     

蓖麻油水性聚氨酯树脂的合成与性能的研究

采用蓖麻油(C．O．)、聚醚(N210)、二异氰酸甲苯酯(TDI)和二羟甲基丙酸(DMPA)反应合成了聚氨酯脲水分散液，研究了C．O．／N210的质量比、亲水单体含量、NCO／OH摩尔比和NH／NCO摩尔比对聚氨酯乳液及涂膜性能的影响，并应用傅立叶红外光谱仪(FT—IR)测定反应产物的结构。研究发现C．O．可提高水性聚氨酯涂膜的物理机械性能和耐水性，当C．O．／N210的质量比为1：1、NCO／OH摩尔比为1．6：1、DMPA添加量为5．5％、NH2／NCO摩尔比为0．50：1时合成的水性聚氨酯涂料具有较好的成膜性、较高的硬度、优异的附着力和较好的耐水、耐油性。     

丙烯酸异冰片酯改性水性聚氨酯的合成及其表征

通过乳液聚合法制备了丙烯酸异冰片酯(IBOA)改性水性聚氨酯(WPU)复合乳液,考察了引发剂用量、反应温度、IBOA/WPU质量比及保温时间对单体转化率、胶膜吸水率及拉伸强度的影响,同时采用正交试验对工艺条件进行了优化。研究结果表明,较适宜的反应条件为IBOA与WPU固体组分质量比为1∶3,引发剂过硫酸铵(APS)用量为IBOA单体添加量的0.5%,反应温度80℃,保温熟化3 h。利用傅立叶变换红外光谱、透射电子显微镜、热重分析等测试方法对复合材料的性能进行了表征,并探讨了性能与结构的关系,结果显示单体的平均转化率达97.35%,改性水性聚氨酯的吸水率达到5.94%,拉伸强度达到27.17 MPa。制备的乳液为核壳结构,乳液稳定性良好;胶膜发生的热降解分别由硬段降解和软段降解造成。     

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。     

聚氨酯/木质素-丙烯酸酯复合乳液研究

合成了木质素-丙烯酸酯乳液;将该乳液与水性聚氨酯乳液复配得聚氨酯/木质素-丙烯酸酯复合乳液.比较了聚氨酯乳液、丙烯酸酯乳液、聚氨酯与丙烯酸酯共混乳液、木质素-丙烯酸酯乳液及聚氨酯/木质素-丙烯酸酯复合乳液的粒径及各乳胶膜的力学性能、热稳定性及耐水、耐溶剂性.结果表明:木质素-丙烯酸酯乳液与聚氨酯乳液的复合对粒径影响并不显著,复合提高了聚氨酯乳胶膜的耐水性和热稳定性,但其耐溶剂甲苯性、拉伸强度和断裂伸长率有所下降.     

超支化水性聚氨酯羟基组分的制备及成膜性能研究

以季戊四醇为核，丙烯酸甲酯和二乙醇胺的加成产物为单体合成了端羟基超支化聚（胺-酯），将其接枝到端-NCO的聚氨酯预聚体上得到了超支化的水性聚氨酯羟基组分。探讨了温度和时间对羟基组分中-NC0含量的影响，采用化学滴定、红外光谱（FTIR）等方法对产物进行了表征和分析。结果表明：适宜的反应温度为75℃，反应时间为6h；以DesmodurDN作固化剂可以制得性能良好的漆膜。漆膜附着力可达到1级，耐冲击强度50cm，铅笔硬度3H，耐水性24h无变化。     

改进水性聚氨酯性能的方法研究进展

针对水性聚氨酯存在的干燥速度慢、初黏性低、耐水性差、固含量低等问题,人们进行了大量的研究工作,目前已经取得了显著进展。作者对近年来在提高水性聚氨酯耐水性、耐热性、固含量、初黏性及干燥速度等方面的相关研究成果进行了概括总结。     

造纸涂料用丙烯酸增稠剂的合成

通过乳液聚合合成了造纸涂料用的增稠剂，最佳条件是：所用乳化剂以阴离子与非离子复合为优，阴离子与非离子的比例为1．5：1，乳化剂的质量用量为1．5％；所用单体中疏水单体丙烯酸乙酯占70．6％、亲水单体丙烯酸占29．4％、交联剂占O．4％～O．6％；引发剂的质量用量为O．15％～O．24％(单体量的)；羟甲基丙烯酰胺的质量用量为1％～1．4％；乳液固含量以28％～30％为宜；乳液的pH值达4时乳液稳定。     

松香基水性聚氨酯丙烯酸酯复合乳液的研制

以富马海松酸水性聚氨酯(FWPU)和甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)等为主要原料,合成富马海松酸型水性聚氨酯-丙烯酸酯复合乳液(FWPUA)。探讨了引发剂的种类和用量及丙烯酸酯加入量等因素对反应的影响。对所得产品进行了红外光谱分析,并测试了漆膜的拉伸强度、镜面光泽、摆杆硬度和耐溶剂性。结果表明:用偶氮二异丁腈和过硫酸铵为复合引发剂,引发剂用量为0.8%,丙烯酸酯的加入量为30%时,复合乳液的拉伸强度、摆杆硬度、耐水性、耐碱性、耐醇性和镜面光泽均有不同程度的提高。     

Study on Synthesis of Hybrid Emulsion of Rosin-based Waterborne Polyurethane-acrylate

以富马海松酸水性聚氨酯( FWPU)和甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)等为主要原料,合成富马海松酸型水性聚氨酯-丙烯酸酯复合乳液(FWPUA).探讨了引发剂的种类和用量及丙烯酸酯加入量等因素对反应的影响.对所得产品进行了红外光谱分析,并测试了漆膜的拉伸强度、镜面光泽、摆杆硬度和耐溶剂性.结果表明:用偶氮二异丁腈和过硫酸铵为复合引发剂,引发剂用量为0.8％,丙烯酸酯的加入量为30％时,复合乳液的拉伸强度、摆杆硬度、耐水性、耐碱性、耐醇性和镜面光泽均有不同程度的提高.     

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。     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.