无机填料对NMMO法纤维素包装膜性能的影响

利用NMMO技术溶解纤维素,并向纤维素溶液中添加无机填料制备成膜,研究了不同填料种类和添加量对纤维素包装膜力学性能的影响,比较了无机填料用硅烷偶联剂处理前后纤维素包装膜力学性能的变化.结果表明:SiO2、多孔沸石、CaCO3、和TiO2添加量(质量分数)分别为1.5%,1%,0.5% 和0.1%时制备的无机充填纤维素包装膜的力学性能较好;1%硅烷偶联剂处理后的无机充填纤维素包装膜力学性能更好.     

NMMO工艺纤维素膜结构与性能的研究

以纤维素为原料,N-甲基吗啉-N-氧化物(简写NMMO)为溶剂,采用相转化法制备非对称纤维素膜.利用扫描电子显微镜对NMMO工艺纤维素膜的微观结构进行了观察,分析了不同纤维素浆粕、聚合度、铸膜液浓度、溶解温度及凝固浴温度等工艺参数对成膜结构和性能的影响.     

溶解工艺对离子液体法纤维素膜力学性能的影响

利用1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为溶剂制备纤维素膜,探讨了浆粕种类、浆粕质量分数、溶解条件等对纤维素膜力学性能的影响。研究表明:聚合度为1460,质量分数为6%的针叶木浆,在溶胀8h,90℃溶解条件下制得的纤维素膜有较好的力学性能。     

以N-甲基吗啉-N-氧化物为溶剂的纤维素氨基甲酸酯纤维的制备及性能

以纤维素氨基甲酸酯(CC)为原料,采用Lyocell工艺,以N-甲基吗啉-N-氧化物(NMMO)为溶剂,通过干湿法纺丝成功制备了CC纤维,并采用X射线衍射、力学性能测试、热重分析、扫描电子显微镜等方法对所得CC纤维的结构与性能进行了研究。结果表明,CC能够很好地溶解于NMMO溶剂中,所纺制的CC纤维具有纤维素Ⅱ晶型结构;随着喷头拉伸比的提高,纤维力学性能提高;纤维表面光滑、结构致密,具有较好的热稳定性和抗原纤化性能。     

羧甲基纤维素增强膜的制备及性能

目的为了获得一种可用于食品包装的羧甲基纤维素增强膜。方法以羧甲基纤维素(CMC)为成膜基底,甘油为增塑剂,分别将质量分数为1%,3%,5%和10%的纳米纤维素(NCC)添加到CMC中,共混流延制备羧甲基纤维素增强膜(CMC-NCC)。结果 NCC的加入,提高了CMC的力学性能和对水蒸气的阻隔性能,还提高了CMC的热性能。FT-IR分析结果表明,CMC与NCC两者间形成了分子间氢键;XRD分析结果表明,NCC可以改变CMC的结晶排列。当添加质量分数为5%的NCC时,CMC-NCC的拉伸强度比纯CMC膜提高了25.6%,断裂伸长率降低了21.3%,透湿量降低了9%,热稳定性提高了2%,透光率维持在87%以上。结论 CMC增强膜具有力学性能高、阻湿性能好等优点,NCC提高了CMC的成膜品质。     

成膜条件对NMMO工艺纤维素膜拉伸强度的影响

以纤维素为原料,N-甲基吗啉-N-氧化物(简写NMMO)为溶剂,采用相转化法制备非对称纤维素膜.对该工艺法成膜的拉伸强度的影响因素进行了研究,以期为提高薄膜性能提供理论基础.实验结果表明:随着溶解纤维素的温度的升高,薄膜拉伸强度降低;随着刮膜时所施加的外力的增大,薄膜的拉伸强度增强;随着凝固浴温度的升高,薄膜的拉伸强度降低;随着塑化剂(甘油)浓度的增加,薄膜拉伸强度降低.     

天然纤维素纤维的溶解及成膜性能研究

采用电晕处理方法来活化棉纤维表面,然后用不同浓度(质量分数,后同)配比的NaOH/尿素和NaOH/硫脲,2种溶剂体系来溶解该纤维,通过对纤维素溶解度和纤维素溶液成膜性能的研究,发现电晕处理是一种很好的表面活性处理方法,其处理功率的大小,对纤维素的溶解度和成膜性能有较大影响.另外,NaOH/硫脲溶剂体系的溶解性能更优,其纤维素溶液成膜性能更好.     

氯化铵改性Lyocell纤维的研究--(Ⅱ)氯化铵对Lyocell纤维结构与性能的影响

在纤维素/NMMO·H2O溶解纺丝体系中,氯化铵改性得到的Lyocell纤维的结晶结构为纤维素Ⅱ和Ⅲ的混合结晶结构;在相同的纺丝条件下,少量氯化铵存在可以明显改善Lyocell纤维的力学性能,对于平均聚合度为818的棉浆纺丝液(纤维素质量分数为9%),加入0.5%的氯化铵(以纺丝液质量为基准)时,得到的Lyocell纤维拉伸强度比未加氯化铵时提高约30%.通过研究氯化铵对最终Lyocell纤维结构与性能的影响,提出了氯化铵改善Lyocell纤维力学性能的机理模型.     

载银纳米纤维素/聚乙烯醇复合膜的制备及性能研究

目的制备一种具有良好力学性能和抑菌性能的新型抗菌聚乙烯醇复合膜。方法通过酸水解微晶纤维素制备纳米纤维素,经高碘酸钠氧化获得醛基纳米纤维素,加入银氨溶液原位合成载银纳米纤维素(Ag-DCNC)。以聚乙烯醇(PVA)为成膜基底,加入Ag-DCNC共混流延制备载银纳米纤维素/聚乙烯醇复合膜。结果 Ag-DCNC体积分数为3%时,复合膜的拉伸强度比纯PVA膜提高了8.8%。Ag-DCNC体积分数为5%的复合膜对大肠杆菌和金黄色葡萄球菌均具有较好的抑菌效果。结论载银纳米纤维素/聚乙烯醇复合膜具有较好的力学强度,对2种细菌均有良好的杀菌效果。该材料不但具有良好的性能,而且合成工艺简单,可以作为一种很有前途的抑菌膜用于包装行业。     

HPMC/KGM水溶性包装薄膜的制备及性能研究

目的以魔芋葡苷聚糖(KGM)为基体,加入羟丙基甲基纤维素(HPMC)改性制备水溶性包装薄膜,探索HPMC改性后其力学性能最佳时HPMC的质量分数。方法通过将HPMC,KGM依次加入去离子水中制备共混溶液,再采用流延法制备薄膜,调节HPMC质量分数,测试并分析对薄膜结构和性能的影响。结果随着HPMC质量分数的增加,薄膜的拉伸强度和断裂伸长率呈先增大后减小的趋势,存在最大值;其水溶性基本呈逐渐降低的趋势,水溶性降低的幅度不大,仍能满足水溶性包装的需求;透光度逐渐升高,雾度逐渐降低,有利于应用在包装中。结论 HPMC和KGM质量分数为1%的成膜液,在HPMC质量分数为总量的20%时,薄膜力学性能较好。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.