改性瓜尔胶/聚氨酯复合微球的制备及性能研究

采用环氧丙烷改性瓜尔胶制备得到羟丙基瓜尔胶,再将其与聚氨酯复合制备微球,并对复合微球的性能进行了研究。结果表明:羟丙基瓜尔胶含量在0.1%~0.3%时,复合微球球形较好;溶胀度随着羟丙基瓜尔胶含量的增加而增加;扫描电镜结果显示,复合微球表面有孔隙,内部呈半中空状态;复合微球的降解速率在碱性环境下较快,酸性环境下较慢;羟丙基瓜尔胶含量越高,药物释放速率越快。     

阳离子羧甲基羟丙基瓜尔胶的制备及其助留助滤性能研究

以1-烯丙基-3-甲基咪唑乙酸鎓盐([AMIM]Ac)为反应介质,3-氯-2-羟丙基三甲基氯化铵(CTA)、氯乙酸钠、环氧丙烷为改性剂,创新性的一步制备了阳离子羧甲基羟丙基瓜尔胶(CCMHPG)。研究了3种改性剂用量、碱用量、反应温度、反应时间对产物取代度和粘度的影响,确定了最佳制备条件。经测定,反应产物的阳离子取代度为0.24,羧甲基取代度为0.41,羟丙基取代度为0.36,产物水溶性较好,1%水溶液粘度达1 072 mPa·s。CCMHPG的红外谱图和~1H NMR谱表明季铵基团、羧甲基和羟丙基均已成功接枝到瓜尔胶分子上,电镜照片显示颗粒表面出现了褶皱及鳞片状裂纹。将CCMHPG/PAC二元微粒体系用于脱墨废纸浆,PAC添加量为0.8%、CCMHPG添加量为0.04%时的留着率为94.3%,打浆度为43°SR。     

瓜尔胶与甲基丙烯酸缩水甘油酯的接枝共聚合

以硝酸铈铵(CAN)为引发剂,采用溶液聚合法,制备了瓜尔胶与甲基丙烯酸缩水甘油酯的接枝共聚物(GGgGMA).研究了反应条件对接枝率的影响,在反应温度为50℃,瓜尔胶浓度为5g/L,硝酸铈铵占瓜尔胶单体质量分数为12%,甲基丙烯酸缩水甘油酯用量为4 mL,反应时间为6h时,接枝率达最大值,并对接枝共聚物用红外光谱FT-...     

甘蔗渣超微粉/瓜尔胶共混体系的相容性研究

利用流变仪考察了甘蔗渣超微粉(BP)/瓜尔胶共混体系的相容性。对共混物进行稳态剪切扫描和动态频率扫描测试后,根据Utraki原理、复合黏度、储存模量及损耗模量分析、Cole-Cole曲线,以及时温叠加原理等理论对数据进行处理分析,发现BP/瓜尔胶=50/100(质量比)时,两者相容性较好。同时,扫描电镜结果表明,随着BP含量的增多,BP与瓜尔胶两者相容性逐渐变差,与流变分析结果一致。     

醇对瓜尔胶高分子水溶液黏度的影响

潮定了异丙醇和乙二醇对瓜尔胶高分子水溶液黏度的影响,发现随着异丙醇的加入,瓜尔胶高分子水溶液的特性黏数逐渐减小,Huggins相互作用参数会逐渐增加;与此相反,随着乙二醇的加入,瓜尔胶高分子水溶液的特性黏数逐渐增加,Huggins相互作用参数却逐渐减小.醇和瓜尔胶高分子之间缔合导致高分子链疏水性质和空间位阻效应的改变,...     

丙烯酰胺-阳离子瓜尔胶的低温接枝聚合

用硫酸铈铵引发阳离子瓜尔胶与丙烯酰胺的低温(10℃)水溶液接枝聚合,重点研究单体与引发剂浓度对接枝参数的影响规律,获得了最佳聚合条件。实验表明,阳离子瓜尔胶与丙烯酰胺的聚合速度明显快于未改性瓜尔胶;随着单体浓度的增加,转化率、接枝率逐渐增加,接枝效率高达95%;进一步增加单体浓度(>1.3 mol/L),转化率、接枝率下降速度较快,接枝效率下降缓慢;随着引发剂浓度增加,转化率和接枝率增加到最大值,而引发剂浓度继续增加(>3.3×10-4mol/L),所有接枝参数下降。红外光谱图和热失重数据证实发生了接枝聚合反应。     

苯乙烯/黏土协同作用对瓜尔胶复合高吸水凝胶性能影响

在瓜尔胶-g-聚丙烯酸钠/无机黏土(GG-g-PNaA/Clay)体系中引入疏水单体苯乙烯(St)参与接枝共聚,水溶液聚合法合成了瓜尔胶-g-聚(丙烯酸钠-co-苯乙烯)/无机黏土(GG-g-P(NaA-co-St)/Clay)复合凝胶。用红外光谱、紫外光谱和扫描电镜对复合凝胶进行了表征,考察了St与无机黏土的协同作用对凝胶三维网络和溶胀性能的影响。实验结果表明,当黏土的质量分数为10%时,随着St的加入,凝胶平衡溶胀倍率(Qeq)呈现先增大后降低趋势;当St质量分数为1.5%时,凝胶Qeq达到最大值。St与凹凸棒黏土、海泡石和蛭石协同作用,不仅使复合凝胶表面形貌粗糙度增加,孔洞增多,而且也使Qeq分别提高了48.9%、50.3%和37.5%。此复合凝胶在0.9%NaCl溶液和一定pH溶液中的Qeq也明显提高,并且经过5次溶胀-去溶胀平衡后,均表现出良好的盐和pH响应性。     

浙江丰利瓜尔胶粉碎机市场受宠

<正>日前,国家高新技术企业浙江丰利粉碎设备有限公司迎来了一批又一批客商,他们专门前来订购瓜尔胶专用超微粉碎机。最近一种名叫瓜尔胶的粉体受到了市场热捧,从而带动了加工设备的热销。瓜尔胶是由瓜尔豆籽经磨碎、筛分、吹风除皮和胚芽、胚乳处理等工序加工制成的自由流动粉末。瓜尔胶主要分为食品级和工业级两种,是已知的最有效和水溶性最好的天然聚合物。其独特的分子结构特点及天然性使其迅速成为性能优越的新型环保造纸助剂。同时它还被广泛应用于食品、制药、化妆品、个人保健、石油、粘蚊剂、造纸和纺织印染等行业,用     

瓜尔胶-g-聚丙烯酸/OMMT纳米复合吸水性树脂的制备与表征

以瓜尔胶(GG)、季按盐改性的蒙脱土(OM-MT)和丙烯酸(AA)为原料,N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,在水溶液中通过接枝聚合反应制备了瓜尔胶-g-聚丙烯酸/OMMT纳米复合吸水性树脂.研究了OMMT的含量、MBA的浓度对产物吸水倍率的影响,考察了OMMT的引入对产物反复溶胀性能的影响.并用傅利叶变换红...     

交联度对瓜尔胶-g-聚丙烯酸/腐植酸钠高吸水性树脂性能的影响

以天然瓜尔胶(GG),丙烯酸(AA)和腐植酸钠(SH)为原料,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸铵(APS)为引发剂,采用水溶液聚合法制备了不同交联度的瓜尔胶接枝聚丙烯酸/腐植酸钠(GG-g-PAA/SH)高吸水性树脂。研究了交联度对树脂的表面形态、溶胀动力学、盐敏感度和反复溶胀性能的影响。扫描电镜(SEM)和溶胀性能测试结果表明,交联度的增加可以改善高吸水性树脂的均匀度,提高吸水速率,降低对盐的敏感度,以及改进树脂的反复溶胀性能。     

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 Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

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.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

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.     

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.