MBHD四元共聚物乳液的合成与表征

合成了含有甲基丙烯酸羟乙酯（ＨＥＭＡ）和甲基丙烯酸二甲氨基乙酯（ＤＭＡＥＭＡ）的四元共聚物乳液（ＭＢＨＤ乳液）,研究了乳化单体加入方式、聚合温度、非离子和阴离子乳化剂配比和用量及ＨＥＭＡ和ＤＭＡＥＭＡ用量对共聚物乳液的粒径及其分布、粘度和表面张力的影响。间歇聚合过程由于水相成核较多而使所得乳液的粒径较小,粒径分布较宽、乳液粘度和表面张力较大,官能团单体ＨＥＭＡ和ＤＭＡＥＭＡ用量增大使共聚物乳液的表     

甲基丙烯酸-2-羟丙酯/苯乙烯分散共聚合的研究

采用梳型结构分散剂,对亲水性单体甲基丙烯酸－2－羟丙酯（HPMA）的分散聚合进行了研究。通过反应在不同结构分散剂存在下表现的不同的动力学特征,提出了反相微悬浮成核机理。并通过HPMA与共聚单体苯乙烯（St)分散共聚合动力学规律的研究,证实了这种成核机理的存在。认为亲水性单体HPMA的分散聚合存在两种机理,均相成核机理和反相微悬浮机理,当采用F－1分散剂时倾向于遵循反相微悬浮成核机理。而且共聚单体苯乙烯,反应比例越小越倾向于反相微悬乳机理,当采用F－2分散剂时反应倾向于均相成核机理,而且苯乙烯单体共聚的引入,使聚合速率变快,有利于提高体系的稳定性。     

St-MMA-AA三元无皂共聚胶乳性质的研究Ⅰ.胶粒形态、大小及分布

以苯乙烯（Ｓｔ）、甲基丙烯酸甲酯（ＭＭＡ）为主单体,丙烯酸（ＡＡ）为功能单体进行了无皂乳液批量共聚合,用ＴＥＭ和ＱＥＬＳ观测了胶粒结构形态、大小及分布,探讨了功能单体ＡＡ浓度、引发剂ＡＰＳ含量、体系ｐＨ值、聚合温度及Ｓｔ／ＭＭＡ配比对胶粒形态、大小的影响。结果表明,Ｓｔ－ＭＭＡ－ＡＡ三元无皂共聚胶粒呈核－壳结构,随「ＡＡ」增大。粒径减小,分散系数增大;随「ＡＰＳ」守大,粒径出现最大值,分散系数增大;随ｐＨ值调节剂ＮａＨＣＯ３浓度增大及ＭＭＡ比例增大,粒径变化复杂,且分散系数也相应变化;随聚合温度提高,粒径增大,分散系数增大。     

苯乙烯与丙烯酸酯在微乳液中的共聚合

分别以γ射线和过氧化苯甲酰（ＢＰＯ）引发苯乙烯（Ｓｔ）／丙烯酸甲酯（ＭＡ）,Ｓｔ／丙烯酸丁酯（ＢＡ）在微乳液中共聚合,微乳液共聚合与本体共聚合相比,两者之间存在明显的差异,两种引发剂之间也不相同,在微乳液共聚合的聚合初期,ＢＰＯ引发时,共聚合场所为大聚合物粒子的内核;而γ射线引发时,为单体溶胀胶束的乳化剂层。     

Ｓt—MMA—AA三元无皂共聚胶乳性质的研究：Ⅱ．胶乳中—ＣＯＯＨ分布

以苯乙烯（Ｓt)、甲基丙烯酸甲酯（ＭＭＡ）为主单体、丙烯酸（ＡＡ）为功能单体进行了无皂乳液批量共聚合。用电导滴定法测定了羧基在胶乳中的分布,讨论了功能单体ＡＡ浓度、引发剂ＡＰＳ含量、体系ＰＨ值,聚合温度及Ｓt/MMA比例对胶乳中－ＣＯＯＨ分布的影响。结果表明,随ＡＡ浓度增大,表面羧基百分比减小、而包埋百分比增大、胶粒表面羧基密度增大。引发剂ＡＰＳ浓度、MAＭＡ比例及聚合温度的提高,不利于羧基分布在乳胶粒表面、胶粒表面羧基密度减小。体系ＰＨ值增大,有利于羧基位于胶粒表面、表面羧基密度有所增加。     

MA—VA乳液共聚合反应动力学及胶粒形态表征

用一步法及半连续法对丙烯酸甲酯和醋酸乙烯酯进行了乳液共聚合。通过气相色谱法对共聚单体转化率的测试以及胶膜力学，耐水性能及最低成膜温度测试，表明一步法ＭＡ－ＶＡ共聚胶粒具核壳结构。其核由富ＭＡ单元共聚物组成，而外壳则是ＰＶＡ均聚物，并在此基础上对本体系的乳液共聚机理进行了探讨。     

高固含量共聚物乳液聚合过程研究

合成固含量６５．４％的高固含量ＢＡ／ＭＭＡ／ＭＡＡ共聚物乳液。研究了共聚合过程中乳液胶粒粒径、粒子数、粒子形态、电导、流变性及聚合速率等。结果表明,随着聚合的进行,乳胶粒粒径变大,粒子数减少,粒度分布变宽;体系的粘度呈增大的趋势,固含量在６０％左右时,体系的粘度忽然变大,在单体刚加完时达最大值,保温反应过程中粘度变小;单体与引发剂同步滴加,聚合反应较平稳;此聚合属于无规共聚。     

氧化还原引发体系连续引发丙烯腈与丙烯酸乙酯乳液共聚合

用氧化还原引发剂在低温下研究了丙烯腈（M1）和烯酸乙酯（M2）的乳液共聚合。考察了聚合温度，乳化剂浓度对聚合的影响，结果表明，随温度升高和乳化剂浓度增大，单体的转化速度加快，聚合物分子量增大，乳液更为稳定。用激光粒径分析仪考察了20℃聚合中乳胶粒子大小的变化，发现聚合过程中的成核和增长均在胶束中进行,以及单体液滴在高转化率时仍存在。这两种单体的乳液共聚合物竞聚率也得到确定：r1=1.90,r2=1.00。     

无皂苯丙乳液的粒径与成核机理

研究了甲基丙烯酸甲酯(MMA)-丙烯酸丁酯(BA)-苯乙烯(St)-甲基丙烯酸(MAA)四元无皂乳液聚合体系中各种因素对单体转化率、乳胶粒大小及分布的影响,并对其成核机理进行了分析。结果表明,在引发剂用量一定的条件下,引发剂的加入方式对单体转化率和乳胶粒的单分散性均有很大的影响;引发剂含量增大,聚合温度升高,单体转化率先升高后趋稳定,乳胶粒粒径和分散度先减小后增大;反应性乳化剂量增大,乳胶粒粒径和分散度均逐渐减小。在所研究的条件下,含有反应性乳化剂的无皂苯丙乳液聚合体系以均相成核为主。     

SMA共聚合反应及改性的研究

概述了苯乙烯－马来酸酐（ＳＭＡ）的共聚合反应、改性方法及应用。分别阐述了ＳＭＡ交替区聚物和无规共聚物的聚合机理和实施方法。在低温和非极性介质中,采用油溶性引发剂,可得到ＳＭＡ交替共聚物,而在极性介质和高温条件下,则可得到ＳＭＡ无规共聚物。通过对其引入极性基团或在主 止引入第三单体等手段,可使共聚物得到改性。此外,还分别讨论了各种因素如溶剂极性、温度、引发剂用量和聚合方法等对这两类ＳＭＡ的结构和性能     

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.