Preparation of silver hydrosols using polyethylene glycol modified with vinyl pyrrolidone

Hydrosols containing silver nanoparticles were prepared from copolymers of ethylene glycol (EG) and vinyl pyrrolidone (VPy). The copolymers were synthesized using a macro-azo-radical initiator appended with EG units. The hydrosols were prepared by simply stirring the copolymers with AgNO₃ in water at room temperature. The nanoparticles conferred thermal stability to the hydrosols, up to 80 °C. Spectroscopic, thermal, and gas chromatography analyses revealed that the silver nanoparticles were protected by EG and carbonyl groups with strong interaction between silver and the oxygen species of EG and VPy.     

Absorption and scattering of light in nanodiamond hydrosols

Scattering and absorption of optical radiation in hydrosols of detonation nanodiamonds (DND) have been studied. Experimental data are presented on the spectral response of the optical density of DND hydrosols prepared by different techniques and in different concentrations. The size distribution of DND particles in these hydrosols was investigated by dynamic light scattering (DLS). The experimental data are compared with calculations. The calculations were performed on models including both the structure of a single DND particle made up of a diamond core and a thin graphite-like shell and the size distribution of the DND particles. A comparison of experiments with the calculation provided a possibility of refining the model of the DND particle and gaining insight into the nature of particle aggregation. It is demonstrated that the combined use of two methods of investigation, which deal with the spectral response of optical density and dynamic light scattering, offers valuable information on the nature of DND hydrosol coloring and the results of particle size determination.     

水羟硅钠石的制备与表征

水羟硅钠石（kenyaite）以其良好的离子交换性、吸附性和热稳定性而被广泛应用于催化和吸附等领域。本文以高纯度且价格低廉的沉淀白炭黑为硅源、以碳酸钠（分析纯）和氢氧化钠（分析纯）为碱源,水热法制备了高纯度的单一晶相的水羟硅钠石,考察了反应时间和反应温度对制备的影响。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、红外光谱仪（IR）、X射线荧光光谱仪（XRF）和同步热分析仪等对样品进行了测试表征。实验结果表明,温度是影响kenyaite制备的主要因素,单一晶相水羟硅钠石的最佳晶化合成条件为晶化温度为180℃,晶化时间为24h,所制备的水羟硅钠石形态为玫瑰花形且其热稳定性在350℃以下。     

CuMgAl类水滑石的制备和表征

用盐-碱制备法合成了CuMgAl三元类水滑石化合物。探讨了原料配比、合成方式、水热处理温度和时间对合成过程的影响,筛选出合成HTLcs的适宜条件,并对HTLcs结构的热稳定性进行初步研究。结果表明,制备HTLcs主要取决于pH值,同时由于Cu2+的姜-太勒效应,合成结构单一的CuMgAl类水滑石要求原料配比中n(Cu)∶n(Mg)不得超过1.0,CuMgAl-HTLcs热稳定性较差,300℃焙烧2h结构破坏,600℃开始烧结,在300~500℃之间,随焙烧温度提高所得复合氧化物比表面积增大,最高可达200 m2/g。     

羟基磷酸铁铵的制备与表征

采用硫酸亚铁和磷酸为原料,在尿素存在的条件下,水热合成得到高纯度的羟基磷酸铁铵。研究发现,反应温度不同得到的羟基磷酸铁铵的结晶度会有所不同,形貌差异较大。利用XRD、SEM、TG-DTA和红外分析等手段对制备的样品组成、结构、晶型和形貌做分析表征,分析了羟基磷酸铁铵在加热过程中的相变过程。结果表明,在静态羟基磷酸铁铵中,磷酸和铁具有固定的化学计量比,经高温煅烧后得到高纯度磷酸铁,可应用其制备锂离子电池正极材料磷酸铁锂的前驱体,且此法合成工艺简单,具有良好的工业应用潜质。     

Particulate processes in freshly prepared silver iodide hydrosols part III. Disagreement between experimental results and the existing models of silver iodide hydrosols

Silver iodide hydrosols prepared in statu nascendi exhibit some specific effects that cannot be explained on the basis of the existing models of silver iodide hydrosols. These effects are acceleration of a heterogeneous exchange process caused by coagulation of the system, and different aggregation number obtained in the same system applying two different exchange methods. In order to explain these effects, a comparison has been made of the differences between the data calculated on the basis of the existing model of silver iodide hydrosols and the values determined by radiometric, optic, and sedimentation analysis. The previous assumption on the existence of a new structural form of silver iodide, characteristic of stable silver iodide hydrosols, has been confirmed. This new structural form of silver iodide transforms into known hexagonal and cubic modifications during the aggregation of primary particles of silver iodide to secondary ones. The properties of the new structural form of silver iodide are predicted.     

Preparation and characterization of soluble polyimides

Two kinds of soluble polyimides from pyromellitic dianhydride with Congo red and 4-sulfanilamide were prepared, respectively. Their structures were characterized by IR and ¹H-NMR, and the thermal properties were investigated by DSC and TG–DTA. © 1995 John Wiley & Sons, Inc.     

Preparation and characterization of glucosylated aminoglycerophospholipids

Natural aminophospholipids were isolated from egg yolk and from human red blood cells. Glucosylated ethanolamine and serine phosphatides were prepared by exposing synthetic and natural aminophospholipids to glucose for 3–18 h at pH 7.4. The glucosylation products were resolved from parent phospholipids by normal-phase high-performance liquid chromatography and were identified by on-line mass spectrometry with an electrospray interface. The soft ionization method allowed us to detect the glucosylation products as molecular ions of the Schiff bases. The Schiff bases could be stabilized by sodium cyanoborohydride reduction. The molecular species of the ethanolamine and serine phosphatides reacted in proportion to their molar concentration in the mixtures. The yields of the glucosylation products varied with time of reaction and the concentration of glucose in the medium. At 50 mM glucose and 0.6 mg/mL phosphatidylethanolamine, 20% of the aminophospholipid was glycated in 18 h at 37°C.     

ODF框胶的制备及性能研究

制备了LCD用ODF框胶,采用FTIR-ATR和测定凝胶含量的方法分析了框胶的UV固化速度以及固化程度。采用SEM对ODF框胶中填料的分散状态进行了分析,对ODF框胶的粘接性能进行了考2查。结果表明,在UV固化能量达到1 500 mJ/cm时即可固化完全,凝胶含量达到99.88%。添加到框胶体系中的有机硅微粉和白炭黑分散均匀,无团聚颗粒存在;ODF框胶对玻璃的粘接强度较高,达到17.90MPa,经过水煮老化处理后对玻璃的粘接强度仍达到15.12 MPa。     

有机膨润土的制备与表征

以提纯后的钠基膨润土为原料,用十六烷基三甲基氯化铵(CTAC)为改性剂制备有机膨润土。研究了原料配比、反应温度和反应时间对有机膨润土性能的影响,获得了最佳改性条件:改性剂用量为100 g膨润土加入115 mmol改性剂,反应温度为60℃,反应时间为90 m in。通过红外光谱(FT-IR)和X射线衍射(XRD)对膨润土的改性效果进行了表征。结果表明:有机季铵盐在不破坏膨润土原有的层间结构骨架的情况下,可以顺利地插层到膨润土层状结构中,使得层间距发生一定的膨胀。以CTAC为改性剂,可以制备出性能优良的有机膨润土。     

TOSPA复合物的制备及其结构表征

4,1′,6′-三氯-2,3,6,3′,4′-五乙酰基蔗糖(TOSPA)是全基团法制备三氯蔗糖的关键中间体,采用苄基三乙基氯化胺(TEBA)为催化剂,氯化亚砜为氯化剂合成了TOSPA。研究结果表明:氯化亚砜用量、反应温度对收率有较大影响,当氯化亚砜过量50%,90℃下反应6h,收率达到90%。实验中制备了TOSPA与甲苯的复合物,并经X射线单晶衍射、核磁、红外、元素分析进行了验证。利用TOSPA与甲苯复合物的物理特性,分离纯化得到了高纯度的TOSPA,具有工业化应用的前景。     

Preparation and characterization of PEGylated terlipressin

Terlipressin was chemically modified by reaction with succinimidyl propionate‐ monomethoxy polyethylene glycol (mPEG‐SPA). To determine the PEGylated degree, the position and the optimized condition for PEGylated terlipressin, the reactions were monitored in different pH value buffers at different molar ratios by reversed‐phase high performance liquid chromatography (RP‐HPLC). Tryptic digestion and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) was used. The results showed that the amount of mono‐PEG‐terlipressin was higher at lower pH value and lower content of PEG. Meanwhile, the amount of di‐PEG‐terlipressin was higher at higher pH value and higher content of PEG under the conditions investigated. The position of PEGylated terlipressin was confirmed by tryptic digestion. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of microencapsulated polythiol

Microcapsules containing curing agent for epoxy were successfully prepared by in situ polymerization with poly(melamine–formaldehyde) (PMF) as the shell material and high-activity polythiol (pentaerythritol tetrakis (3-mercaptopropionate), PETMP) as the core substance. Having been encapsulated, the core material PETMP had the same activity as its raw version. The synthesis approach was so improved that the consumption of polythiol was reduced to a low level. By carefully analyzing the influencing factors including catalyst concentration, reaction time, reaction temperature, feeding weight ratio of core/shell monomers, dispersion rate and emulsifier content, the optimum synthetic conditions were found out. The results indicated that not only core content and size of the microcapsules but also thickness and strength of the shell wall can be readily adjusted by the proposed technical route. The relatively thin shell wall (0.2 μm) assured sufficient core content even if the microcapsules were very small (1–10 μm). The polythiol-loaded microcapsules proved to be qualified for acting as the mate of epoxy in making two-part microencapsulated healing agent of self-healing composites.     

高铁酸钾的制备工艺研究与表征

高铁酸钾是一种新型绿色高效的水处理剂,为了探索经济、高效的制备高铁酸钾的工艺,以次氯酸钙为主要原料通过氧化反应制备高铁酸钾,考察反应时间、反应温度、次氯酸钙用量、重结晶温度和碱度等因素对产率的影响,并采用红外光谱对产物高铁酸钾进行表征。实验结果如下：当反应温度为25 ℃,次氯酸钙的用量为理论值的1.2倍,反应时间为40 min,在冰水浴中重结晶时,反应产率可达75%以上;红外光谱（FT-IR） 对产物的结构表征证明合成产物为高铁酸钾。结果表明以次氯酸钙代替次氯酸钠制备高铁酸钾的工艺是可行的。     

掺锑氧化锡纳米粉体的制备与表征

以SnCl4·5H2O和SbCl3为原料,NH3为共沉淀剂,在表面活性剂存在下,采用室温固相法制备锑掺杂二氧化锡(ATO)纳米粉体。探讨了掺锑量、表面活性剂对ATO粉体性能的影响。运用IR、XRD、TEM、比表面仪(BET)等对ATO粉体进行了表征。结果表明,当锑掺杂量为12.3%时,ATO纳米粉体具有最小电阻率,为3.36Ω·cm,ATO粉体为四方晶红石结构,颗粒形状为近似球形,粒度均匀,一次粒径为10 nm左右。     

环氧化SBS的制备与表征

利用原位环氧化工艺对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)进行了环氧化改性,制得环氧化SBS。红外谱图显示,SBS经环氧化后分子链上出现了环氧基团。研究了环氧化SBS的特性粘数([η])、拉伸性能及耐油性,用热重分析比较了SBS和环氧化SBS耐热性的差异。结果表明,与SBS相比,环氧化SBS的[η]较大,拉伸强度有所提高,断裂伸长率和断裂永久变形变小;耐油性得到改善。     

纳米纤维素的制备与表征

以微晶纤维素为原料,通过硫酸酸解制备获得了纳米纤维素。实验优选获得了酸解制备纳米纤维素的优化条件为:硫酸初始浓度35%,反应温度40℃,酸解时间90 min,此优化条件下,纳米纤维素的产率可达83.55%;SEM和TEM观察产物的形态外貌,确定为纳米级纤维素;XRD分析显示纳米纤维素的结晶度要高于微晶纤维素,而TG分析显示NCC的热稳定性要低于微晶纤维素。     

纳米硒的制备和表征

硒是一种人体必需的微量元素，随着科技的发展，人们对这种物质的利用也越来越广泛。报道了一种以聚乙烯醇作为软模板制备纳米硒的方法，并对所制得的纳米硒进行了表征，研究了反应物的浓度、温度，以及超声等反应条件对产物形貌及粒径的影响。结果表明，当反应体系中亚硒酸浓度为0．01mol／L、抗坏血酸浓度为0．07mol／L、聚乙烯醇质量分数为1．0％、常温下反应5min后可得到均匀稳定的球形红色纳米硒颗粒，平均粒径约30nm。     

多孔羟基磷灰石的制备与表征

羟基磷灰石(HA)以其良好的生物相容性和生物活性成为重要的骨修复材料。实验以α-Ca3(PO4)2为原料采用水热合成法制备了多孔羟基磷灰石板材。借助XRD、SEM和FTIR研究了产物的物相组成、微观结构和化学组成。结果表明:随着水热时间的延长,HA析晶更完整且呈针状分布。经1200℃处理后进行的水热反应,形成的孔较均匀且细小。反应过程吸收了部分CO2,但未进入结构。该材料从结构和尺寸方面考虑能够用于生物医用材料。