聚乳酸/二氧化硅有机无机杂化材料的制备和表征

以聚乳酸(PLA)、正硅酸乙酯(TEO S)为原料,活性单体3-氨基丙基三乙氧基硅烷(APTES)为偶联剂,采用两步法制备PLA/S iO2杂化材料。采用FT-IR、DSC和TEM等技术对杂化材料进行表征。研究结果表明,杂化材料中有机组分和无机组分通过APTES发生了化学键合;材料的玻璃化转变温度(Tg)随着二氧化硅含量的增大而提高;随APTES加入量增大、酰胺化反应温度升高,反应时间延长,杂化材料的溶胶分数减小。     

聚四氟乙烯/二氧化硅杂化材料的性能研究

为解决纳米粒子在聚四氟乙烯(PTFE)树脂中难分散均匀的问题,使用PTFE乳液通过原位溶胶-凝胶法(Sol-Gel)制备了聚四氟乙烯/二氧化硅(SiO2)杂化材料,并对其性能进行了表征与研究.研究表明:杂化材料的拉伸强度在SiO2含量为1.05%(记为FS-2)时达到最大值20.96 MPa,为纯PTFE的两倍;断裂伸长率随着SiO2含量的增加而降低,硬度逐渐升高,接触角由121°降至79°.由SEM结果发现,试样FS-2中SiO2的粒径仅为100 nm左右,但随着SiO2含量的增加,粒径变大.杂化材料的耐热性较PTFE有一定提高,当杂化材料中SiO2含量达到5.00%时,热分解温度由纯PTFE的503℃上升至528℃.     

P(AM PS+AM)/SiO_2高吸水性杂化材料的制备及性能

研究了以2-丙烯酰胺基-2-甲基丙磺酸(AM PS)和丙烯酰胺(AM)共聚物为有机相,通过正硅酸乙酯(TEO S)引入S iO2无机相,采用溶胶-凝胶法制得了P(AM PS+AM)/S iO2高吸水性杂化材料,并着重研究了不同用量的TEO S对材料结构和性能的影响。采用傅立叶红外(FT-IR)、扫描电镜(SEM)等检测方法对材料进行了表征,同时对材料的透光性、吸液性能、热稳定性等进行了评价。结果表明,TEO S用量为5%(相对单体质量百分含量)左右制得的高吸水性杂化材料较为理想。     

(PEO)8LiClO4-TiO2复合电解质膜的制备表征及导电性能

以聚氧化乙烯/高氯酸锂复合物(简记为(PEO)8L iC lO4)为基体,通过钛酸丁酯的水解缩合反应在其中原位生成T iO2粒子,制备了(PEO)8L iC lO4-T iO2复合聚合物电解质膜,采用原子力显微镜(AFM)、差示扫描量热法(DSC)和交流阻抗方法研究了复合电解质膜的形貌、结晶、熔融行为和离子电导率。结果表明,T iO2粒子在基体中分散均匀,加入T iO2后复合电解质体系的玻璃化转变温度和结晶度均有所下降,而电导率明显提高,当T iO2添加量为5%时电导率最大,20℃和80℃的电导率分别为5.5×10-5S/cm和1.1×10-3S/cm。     

原位复合法制备P(AALi-AN-BA)/LiX/SiO2聚合物电解质及其导电性

共聚单体丙烯酸锂(AAL i)、丙烯腈(AN)、丙烯酸丁酯(BA)聚合的同时前驱体正硅酸乙酯(TEOS)水解缩合,在聚合物基体原位生成S iO2粒子,添加复盐L iX(L iC lO4-L iNO3-L iB r共熔盐)后制备了P(AAL i-AN-BA)/L iX/S iO2复合聚合物电解质,用IR和DTA-TG对其进行了表征,采用交流阻抗法研究了电解质膜的离子导电性能。结果表明,原位复合S iO2后体系的热稳定性提高,锂离子传输表观活化能Ea明显降低,电导率增大,当S iO2添加量为10%,L iX含量为75%时,体系的室温电导率达到最大值6.26×10-4S/cm(20℃)。     

可成纤PMMA/SiO2杂化溶胶研究

采用溶胶-凝胶法制备了具有成纤性能的PMM A/S iO2杂化溶胶,分析了反应中体系黏度的变化。实验结果表明,添加了偶联剂的杂化溶胶,在PMM A-TEO S摩尔比为3.8~1时,成纤性能、S iO2含量和产物透明度达到最好的结合点,并用生物显微镜观测了所拉制杂化纤维的外观,用红外光谱表征了PMM A/S iO2杂化材料的化学构成。     

聚氨酯接枝改性环氧树脂的微观结构

由端-NCO基聚氨酯预聚物(PU)与环氧树脂(EP)反应制备了聚氨酯接枝改性环氧树脂(EP-g-PU),考察了PU和活性稀释剂含量及异氰酸酯结构对EP-g-PU固化物玻璃化转变温度(Tg)和微观形貌的影响。结果表明,EP-g-PU固化物的Tg随PU含量增加而升高,随活性稀释剂含量增加而降低;三种异氰酸酯制备的EP-g-PU固化物的Tg顺序为IPDIMDITDI。异佛尔酮二异氰酸酯(IPDI)和二苯基甲烷二异氰酸酯(MDI)型EP-g-PU固化物的断面形貌为以EP为细胞核、PU为细胞壁的两相细胞状结构,甲苯二异氰酸酯(TDI)型EP-g-PU固化物的断面形貌为PU以岛状分布于EP基体中的海岛结构,但岛相也是以EP为细胞核、PU为细胞壁的两相细胞状结构。     

CeO2-ZrO2-聚苯乙烯杂化材料的制备与性能

以非离子表面活性剂P123为模板剂,ZrOCl2.8H2O和Ce(NO3)3.6H2O为原料,制备出CeO2-ZrO2介孔粒子。采用油酸对介孔CeO2-ZrO2粒子进行有机改性后,与苯乙烯原位聚合得到CeO2-ZrO2-聚苯乙烯杂化材料。该杂化材料的热分解温度达到417℃,与纯的聚苯乙烯分解温度相比有显著提高;当CeO2-ZrO2用量达到m(CeO2-ZrO2)/m(苯乙烯)=2/100时,杂化材料的拉伸强度达到最大值42.3MPa;当CeO2-ZrO2用量达到m(CeO2-ZrO2)/m(苯乙烯)=3/100时,杂化材料的缺口冲击强度达到最大值3.18 kJ/m2;有机分子进入CeO2-ZrO2介孔材料孔道内的方式和表面包覆作用,促进了无机粒子与基体间形成强有力的界面粘合,极大改善了聚苯乙烯的力学性能和热性能。     

基体温度对中频脉冲非平衡磁控溅射技术沉积类金刚石薄膜结构与性能的影响

利用中频脉冲非平衡磁控溅射技术在不同的基体温度下制备了类金刚石(DLC)薄膜,采用Raman光谱、X射线光电子能谱(XPS)、纳米压痕测试仪、椭偏仪对所制备DLC薄膜的微观结构、机械性能、光学性能进行了分析。Raman光谱和XPS结果表明,当基体温度由50℃增加到100℃时,DLC薄膜中的sp3杂化键的含量随基体温度的升高而增加,当基体温度超过100℃时,DLC薄膜中的sp3杂化键的含量随基体温度的升高而减少。纳米压痕测试表明,DLC薄膜的纳米硬度随基体温度的增加先增加而后减小,基体温度为100℃时制备的薄膜的纳米硬度最大。椭偏仪测试表明,类金刚石薄膜的折射率同样随基体温度的增加先增加而后减小,基体温度为100℃时制备的薄膜的折射率最大。以上结果说明基体温度对DLC薄膜中的sp3杂化键的含量有很大的影响,DLC薄膜的纳米硬度、折射率随薄膜中的sp3杂化键的含量的变化而变化。     

PU/SiO_2-HDI杂化微胶囊的制备及其在自修复防腐涂层中的应用

以六亚甲基二异氰酸酯(HDI)为芯材,通过界面聚合法和溶胶-凝胶原位生成法制得聚氨酯(PU)/二氧化硅(SiO_2)-六亚甲基二异氰酸酯(PU/SiO_2-HDI)杂化微胶囊。研究了3种催化方式酸催化、碱催化、酸碱催化对杂化微胶囊产率、密封性、热稳定性以及微观形貌的影响,结果表明:与未杂化微胶囊相比,PU/SiO_2-HDI杂化微胶囊的上述性能均有所提高,其中酸碱杂化微胶囊的粒径较大,分布均一,产率为71.24%,在168h浸泡条件下的泄漏率为12.03%,初始分解温度为269.43℃,在杂化微胶囊中具有最佳的性能。同时,将酸碱杂化微胶囊包埋PU防腐涂料基体中,形成的酸碱杂化涂层在盐雾腐蚀168h条件下,其划痕处被愈合,且未出现明显的腐蚀现象,具有较好的自修复和防腐作用。     

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.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

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.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

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.