硬脂酸/TiO_2/CNF超疏水复合材料的制备与表征

研究了一种利用硬脂酸对纳米二氧化钛(Nano-TiO_2)和纤维素纳米纤维(CNF)复合物进行有机表面修饰的新方法,主要包括纳米二氧化钛、纤维素纳米纤维的制备和利用硬脂酸对Nano-TiO_2/CNF复合体系进行有机表面修饰制得超疏水材料三个工艺过程。通过傅里叶变换红外光谱仪(FTIR)和场发射扫描电子镜(SEM)等对所得的样品进行表征,得出硬脂酸中的—COOH基团与TiO_2/CNF复合体系表面的—OH基团发生脱水反应,并将疏水性—CH_3基团引入复合体系中,复合体系表面构建的纳米级粗糙结构协同体系内引入的疏水基团使最终产物具有超疏水性。     

Preparation and characterization of wood/montmorillonite nanocomposites

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.     

液相混合法制备纳米纤维素晶须/ABS复合材料

采用液相混合法制备了纳米纤维增强苯乙烯-丁二烯-丙烯腈(ABS)复合材料,研究了纳米纤维素晶须(NCW)含量对复合材料性能影响。SEM测试表明,添加少量的NCW即会对复合材料的断裂面形态造成明显影响。热重分析发现,NCW的加入会降低复合材料的热稳定性。当NCW含量为10%时,复合材料热分解温度下降20%。红外光谱(FTIR)测试表明,在复合材料中纳米纤维素间的自由羟基和氢键数量明显下降。拉伸性能和动态机械性能测试表明,NCW含量为5%时复合材料的性能增加明显,拉伸强度上升11%,模量上升19%。研究结果表明,采用液相混合法制备纳米纤维素晶须/ABS复合材料时,丙酮溶液和ABS中存在的—CN对改善复合材料的界面相容性尤为关键。     

纤维素纳米晶/金纳米粒子复合虹彩薄膜的制备与表征

以滤纸为原料，采用浓硫酸水解法制备纤维素纳米晶(CNCs),以柠檬酸钠还原法制备金纳米粒子(GNPs),并将GNPs与CNCs以不同质量比共混制备CNCs/GNPs复合虹彩薄膜；并在CNCs/GNPs体系中添加果糖，研究了果糖对等离子吸收共振效应的影响。采用透射电镜、反射光谱、扫描电镜、偏光显微镜、红外光谱、X射线衍射、紫外-可见光谱和圆二色谱对复合薄膜进行分析，探讨了GNPs与CNCs以不同质量比复合时的结构与性能，以及果糖对体系的影响。研究结果表明：CNCs在成膜过程中发生了自组装，形成了左旋的手性层状液晶结构；复合薄膜具有明显的虹彩颜色，具有周期性层状结构和指纹织构，添加GNPs没有改变CNCs本身的官能团，但复合膜具有明显的等离子共振吸收峰并发生蓝移。添加果糖会使薄膜颜色产生红移现象的同时促进GNPs更加均匀地分散，从而增强GNPs的等离子共振吸收效应。GNPs和果糖的加入不会改变CNCs的晶型结构，对纤维素的结晶度也没有影响。     

壳聚糖/纳米TiO2超声降解甲基橙废水

将壳聚糖(CHS)和改性后纳米TiO)2同步复合,制备得到一种新型复合材料.评估了此复合材料超声催化降解甲基橙模拟废水的性能,探讨了废水pH值、纳米TiO2/CHS不同配比、复合膜投入量,时间对脱色率、降解率及其化学耗氧量(COD)的影响,试验结果表明:室温处理50mL0.02g/L的甲基橙溶液最佳条件为:当复合膜投入量为2.0g,吸附剂的配比为1∶6,废水pH为5,时间为60min时,其COD去除率和降解率分别高达93％和99％.     

聚乙烯醇/纳米纤维素晶体复合膜热学性能

以微晶纤维素(MCC)为原料,通过硫酸水解得到纳米纤维素晶体(NCC),再将纳米纤维素晶体与聚乙烯醇复合共混制备聚乙烯醇/纳米纤维素晶体复合膜,研究复合膜的热学性能,同时采用场发射透射电镜(FETEM)、场发射扫描电镜(FE-SEM)、原子力显微镜(AFM)、热重分析(TG)、差示扫描量热仪(DSC)等仪器对纳米纤维素晶体及其复合膜进行表征与分析。结果表明:所制得的纳米纤维素晶体直径约2～24nm,50～450nm长,呈棒状;由FE-SEM图可观察到纳米纤维素晶体与聚乙烯醇具有良好的界面相互作用,但在较大添加量7%时,NCC出现部分团聚,与基体的相容性下降;由TG和DSC分析说明NCC与PVA基体可较好相容,形成了热稳定性较好的复合膜,但当NCC添加量较大时,由于团聚使复合膜热稳定性下降。     

天然纤维微/纳米纤丝改性家具涂料的可行性

纤维素是木材及农作物秸秆的主要组分,约占木材及农作物秸秆质量的50%,在纤维细胞壁中起骨架作用.其化学性质和超分子结构对材料性质和加工性能有重要影响.纤维素微/纳米纤丝是利用物理或化学方法从天然纤维中分离出来的,因为在分离过程中一部分无定形区被破坏,结晶区相对增加,使分离出来的微/纳米纤丝具有较高的刚性.本文简要叙述了天然纤维微/纳米纤丝的分离方法及其作为家具用涂料改性剂的可行性.     

超声波分散纳米TiO2溶液的工艺研究

应用超声波技术对光触媒纳米TiO2溶液的分散性进行研究,分析超声波功率、溶液温度、超声分散时间与溶液放置时间等工艺因素对TiO2分散效果的影响。试验结果表明超声波功率300W、超声分散时间10min、溶液温度20℃、放置时间40min之内,TiO2溶液的分散性良好,为纳米TiO2改性薄竹的应用提供了理论基础。     

纳米TiO2改性薄竹的工艺试验

研究了纳米TiO2改性薄竹机理与工艺,分析薄竹切面、薄竹厚度、浸渍压力与浸渍时间等工艺因素对薄竹附载TiO2效果的影响,并运用X射线光电子能谱与环境扫描电镜技术手段,分析了薄竹改性处理前后的表面元素组成、元素变化、TiO2分布效果。试验结果表明:浸渍时间90 min、浸渍压力0.10 MPa、薄竹厚度0.3 mm、径切面纹理的薄竹、纳米TiO2溶液浓度0.5 g/L、浴比1∶10～20、常温浸渍纳米TiO2溶液改性薄竹工艺是可行的,TiO2附载率约为1.3%。     

Chalcididae undLeucospidae

Ohne Zusammenfassung     

《瑶溪二十四景诗》的山水园林文化机理

古人崇尚自然山水,从对自然山水的喜爱、感悟,发展成对中国传统文化影响深远的山水文化观。《瑶溪二十四景诗》正是受传统山水文化观影响的清代文人刘彤以诗文描述的瑶溪二十四处景色。对景诗的赏析,能感受到瑶溪蕴含的人居环境山水文化,更能为现代“诗文造园”带来启发。现代诗文造园者往往更需要具备学识广博的才能,通晓山水园林文化意境的特点,因地制宜、巧用心思,精细设计施工,才能创作出与环境相融,并能引人共鸣的优秀园林作品。     

混合接种Glomus与Pisolithus菌株对尾叶桉矿质营养吸收的影响

对混合接种ＶＡ菌根真菌苏格兰球菌霉和ＥＣＭ真菌彩色豆马勃影响尾叶桉苗期矿质营养元素吸收情况进行了研究。接种苗根真菌对苗木吸收Ｎ、Ｐ、Ｋ和Ｂ产季了较大的影响,主要体现在促进苗木对上述营养元素的吸收和积累。     

杉木、马尾松、甜槠等林分下土壤养分状况研究

对中等立地上杉木、马尾松,甜槠等林分的土壤养分状况进行了综合比较,结果表明：不同林分对土壤有机质及矿质养分的影响不尽相同,阔叶林能增加土壤有机质积累,改善土壤养分状部;马尾松林对提高土壤有效性Ｎ、Ｐ、Ｋ含量具有一定作用,特别是对提高有效Ｐ作用很大;杉木纯林不利于改善土壤养分状况及土壤理化性质;针阔混交林能改良土壤养分状况,尤其能较好地改良土壤有效性微量元素状况,防止地方衰退,有利于林业持续发展,另     

Lignans ofLinum flavum var.compactum

A new dibenzylbutyrolactone lignan 7.6-dihydroxybursehernin, together with six known lignans (pinoresinol, lariciresinol, secoisolariciresinol,-peltatin,-peltatin, 5-methoxypodophyllotoxin) were isolated from the methanol extracts ofLinum flavum var.compactum. The enantiomeric analysis of pinoresinol and lariciresinol isolated from the species, which are upstream lignans in the lignan biosynthetic pathway, indicated that they are not optically pure, which is in accordance with our recent findings on lignans occurring in other plant species.Parts of this report were presented at the 42nd Lignin Symposium, Sapporo, October 1997; and the 43rd Lignin Symposium, Fuchu, October 1998     

Properties of PP/wood flour/organomodified montmorillonite nanocomposites

In this research, composites based on polypropylene (PP), beech wood flour, and organomodified montmorillonite (OMMT) were prepared and characterized for their properties. The blend nanocomposites were prepared by melt mixing of PP/WF at 50% weight ratios with various amounts of OMMT (0, 3, and 6 per hundred compounds (phc)) in a Hakee internal mixer. Then the samples were made by injection molding. The influence of organomodified montmorillonite contents on clay dispersion, physical and mechanical properties of PP/wood flour composites were investigated. Results indicated that the flexural strength and modulus, tensile strength and modulus increased by addition of 3 per hundred compounds (phc) of organomodified montmorillonite (OMMT), but decreased with 6 phc OMMT addition. However, impact strength, water absorption and thickness swelling of the composites decreased with increasing nanoclay loading. X-ray diffraction patterns (XRD) and transmission electron microscopy (TEM) revealed that the nanocomposites formed were intercalated. Also, morphological findings showed that samples containing 3 phc of OMMT had higher order of intercalation.     

Oak/Douglas-fir/sheep: A three-crop silvopastoral system

A small scale agroforestry study which was begun in 1952 was revisited in 1985 to evaluate the long-term influence of site preparation and grazing on tree growth and survival in a Douglas-fir (Pseudotsuga menziesii)-white oak (Quercus garryana)-sheep silvopastoral system. In 1952–1953, two-year-old Douglas-fir seedlings were planted at the rate of 2500 trees/ha under three levels of site preparation: (1) no treatment, (2) oak thinned by 50%, and (3) oak clearcut. From 1954 to 1960, yearling ewes grazed one-half of each of the three thinning treatments for 3–4 weeks each spring. The conifers have been undisturbed since grazing was discontinued in 1960. Survival of planted conifers averaged 64% in 1985 and did not vary among either site preparation or grazing treatments. From 1964 to 1985, trees on the thinned and clearcut plantations grew an average of 1060 and 990 cm in height, respectively, compared to 900 cm on the unthinned plantation. Diameter at breast height (dbh) averaged 3.8 and 5.6 cm greater on thinned or clearcut plantations, respectively, than on the unthinned control by 1985 (p < 0.05). Conifers on grazed plantations had increased height and dbh growth during the first 12 years of plantation life, averaging 63 cm taller (p < 0.10) and 0.7 cm greater in dbh (p < 0.05) than the ungrazed plots by 1964. By 1985 the difference in height (122 cm) and dbh (1.0 cm) between grazed and ungrazed plantations was not statistically significant. These data suggest that although site preparation can positively influence conifer growth, total clearfelling is no better than thinning oaks. Furthermore, proper grazing can increase height and dbh growth of the conifers during and immediately after the grazing years.