淀粉与丙烯酸接枝共聚物吸水性能的影响因素研究

采用溶液聚合的方法,制备了淀粉与丙烯酸接枝共聚物;用FTIR等方法对共聚产物结构进行了表征;研究了聚合反应温度、糊化时间、丙烯酸中和度、产物烘干温度、丙烯酸与淀粉不同混合比例等因素对接枝产物吸水性能的影响,优化出了在实验室用玉米淀粉和丙烯酸接枝共聚制备高倍率吸水树脂的工艺条件,制备的吸水树脂吸去离子水近1000g/g.     

生物质纤维丝制取高吸水性树脂的研究

以丝瓜络为原料制备羧甲基纤维素钠,进而与丙烯酸接枝共聚制备出高吸水性树脂。分析了丙烯酸用量、交联剂用量、引发剂用量、单体中和度和反应温度等因素对高吸水性树脂性能的影响,并用红外光谱对产物的结构进行了表征。结果表明:合成的高吸水性树脂的吸水倍率达1500g·g-1,在质量分数为0.9%的食盐水中的吸液倍率达115g·g-1。     

丝素蛋白/丙烯酸/丙烯酰胺吸水材料的制备和表征

以具有良好生物分解性能的丝素蛋白(SF)为原料,与丙烯酸(AA)和丙烯酰胺(AM)在水溶液中接枝共聚,合成了丝素蛋白/丙烯酸/丙烯酰胺吸水材料(SF/AA/AM)。通过探讨合成条件对吸水材料吸水倍率的影响,得到较合适的配比参数。SF/AA/AM吸水材料在去离子水、自来水和0.9%NaCl溶液中的吸水倍率分别为220g/g～308g/g,135g/g～210g/g,24.3g/g～34.8g/g。红外吸收光谱显示丝素蛋白与丙烯酸和丙烯酰胺发生了很好的聚合。扫描电镜显示了吸水材料表面沟棱交错,吸水比表面增加。     

低温等离子体处理羧甲基纤维素接枝丙烯酸制备高吸液性树脂的研究

在低温等离子条件下,对漂后蔗渣浆(BP)为原料制成的羧甲基纤维素(CMC)接枝丙烯酸(AA)制备高吸液性树脂的工艺进行单因素分析,得出最佳制备工艺条件为:等离子体放电功率为250W,处理时间为90s,真空度为300Pa,m(CMC)∶m(AA)=1∶9,引发剂与CMC用量比m(K2S2O8)∶m(CMC)=7∶20,中和度为40%时,产物的最大吸盐水倍率为38.5g/g,吸稳定性二氧化氯溶液倍率为27.2g/g。并运用红外光谱(IR)、X-射线衍射(XRD)差示扫描量热(DSC)分析手段,对产品的结构进行了表征。结果表明产物是羧甲基纤维素与丙烯酸接枝共聚形成的,丙烯酸接枝到羧甲基纤维素上使得树脂的吸液能力和热性能得到了很大地提高。同时本研究为蔗渣的高附加值利用提供了一条新途径。     

二甲基二烯丙基氯化铵-丙烯酰胺共聚物的合成及其吸水性能研究

选择二甲基二烯丙基氯化铵(DMDAAc)、丙烯酰胺(AM)为共聚单体,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺(NMBA)为交联剂,乙二胺四乙酸二钠为助剂,通过逐渐滴加单体与引发剂的方法进行聚合反应,合成了二甲基二烯丙基氯化铵-丙烯酰胺共聚物。探索了合成的最佳工艺条件,并对合成的目标产物进行了红外光谱表征,确保合成产物结构的正确性;对共聚物进行了热性能测试,5%热分解温度均大于260.6oC;吸水性能测试表明,共聚物对去离子水和0.9%NaCl水溶液吸水倍率可分别达318、69.2g/g。     

辉光放电电解等离子体法制备羧甲基纤维素/聚乙二醇/丙烯酸高吸水性复合材料及其溶胀性能

在水溶液中,以丙烯酸(AA)、羧甲基纤维素(CMC)和聚乙二醇(PEG)为原料,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,用辉光放电电解等离子体(GDEP)引发制备羧甲基纤维素/聚乙二醇/丙烯酸(CMC/PEG/AA)高吸水性复合材料。采用红外光谱、X射线衍射、扫描电镜和热重分析对复合材料的结构、形貌和热稳定性进行了表征;研究了复合材料在蒸馏水、雨水、0.9%NaCl溶液、黄河水和自来水中的溶胀行为。结果表明,CMC、PEG和AA发生接枝共聚形成高吸水性复合材料,组分间相容性好,表面出现深浅不均匀的沟壑、孔洞和凹槽,热稳定性能良好;复合材料在蒸馏水、雨水和0.9%NaCl溶液中的最大平衡溶胀率分别约为935 g/g、689 g/g、78 g/g;在黄河水和自来水中溶胀动力学行为表现出过溶胀平衡特性,即材料先发生溶胀,达最大值后再逐渐消溶胀到平衡。     

基于西瓜果肉的环保型复合吸水材料的制备研究

通过西瓜果肉(WMF)和中和丙烯酸(AA)的自由基接枝共聚，成功合成了一种基于生物质材料的低成本、环保型的高吸水复合材料(WMF-co-AA),并通过扫描电子显微镜和红外光谱分析仪对其结构和形态进行表征。探究了WMF含量对复合材料溶胀能力的影响，对复合材料的吸水率、保水性、耐热性、耐盐性进行了研究。结果表明，WMF成功地接枝在丙烯酸单体上，且复合材料在去离子水和0.9%(wt,质量分数)NaCl溶液中的最佳吸水率分别为702g/g和70g/g。在pH范围为4～10的溶液、不同的盐溶液及阴离子表面活性剂溶液中也具有优异的溶胀性能，表明其具有良好的pH稳定性和耐盐性。此外，复合吸水材料对多价金属离子具有一定的吸附性能。     

CMS-g-PAA高吸水性复合材料的制备及性能研究

以废弃全棉面膜基布(CMS)和丙烯酸(AA)为原料,采用自由基溶液聚合法制备CMS-g-PAA复合高吸水性材料,并用红外光谱(FTIR)进行表征。研究了吸水性、保水性及反复吸放液性能,采用准一级、二级动力学模型对其吸水溶胀过程进行模拟研究。结果表明,全棉面膜基布和丙烯酸单体之间发生了接枝共聚反应,所合成的CMS-g-PAA复合材料在去离子水和0.9%(质量分数)NaCl溶液的吸水倍率分别可达211.3g/g和45.5g/g,且溶胀过程符合准二级动力学吸附模型。在较高温度和一定压力下,CMS-g-PAA均具有良好的保水性能。反复吸放液性能测试表明循环8次后,去离子水和0.9%(质量分数)NaCl溶液的吸水倍率分别保持了最大吸水倍率的64.9%和44.4%。     

不同种类氧化-还原引发体系对淀粉与丙烯酸接枝产物吸水性能的影响

以玉米淀粉和丙烯酸为主要原料,采用溶液聚合的方法,详细研究了H2O2、K2S2O8-Na2S2O3、Mn3 及Ce4 等不同种类氧化-还原引发体系对淀粉与丙烯酸接枝共聚物吸水性能的影响,用FTIR、XRD、DSC等方法对共聚产物结构进行了表征.通过对不同氧化-还原引发体系的引发机理分析和吸水性能测试结果比较,研究表明采用K2S2O8-Na2S2O3做引发体系时,接枝产物的吸水倍率最高,吸去离子水近1000g/g.     

生物酶活化海藻制备可降解型保水剂

首先对海藻(A)进行温差破壁及生物酶活化处理,再接枝丙烯酸(AA)、丙烯酰胺(AM)制备可降解耐盐型保水剂.考察合成最佳条件,用复配酶对产品进行降解试验.结果表明:当冷冻-融熔次数是2,酶质量(E)/海藻质量(A)=1.0%,丙烯酸质量(AA)/丙烯酰胺质量(AM)=4时产品吸水能力及耐盐性最佳,吸去离子水可达409g/g、吸0.9%NaCl溶液可达112.7g/g,保水剂降解96h后海藻降解率达93.3%.IR表明产品接枝性的存在,DSC表明产品热性能良好,SEM表明产品呈多孔性.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。     

Synthesis and luminescent properties of alkali-metal and ammonium fluorosulfatozirconates and fluorosulfatohafnates

We have synthesized a variety of alkali-metal and ammonium fluorosulfatometallates (titanates, zirconates, and hafnates). The alkali fluorosulfatozirconates and fluorosulfatohafnates have been shown to exhibit efficient roentgenoluminescence (RL) in the UV through visible spectral region, with a maximum at 390–440 nm. Their RL spectra depend significantly on their composition (cation, anion, and water content), coordination of KF and K₂SO₄, and relative amounts of fluorine and SO₄ groups. We have examined the effect of heat treatment on the RL of these compounds. The rubidium and cesium fluorosulfatozirconates Rb₃Zr₂F₉SO₄ · 2H₂O, Cs₂ZrF₂(SO₄)₂ · 2H₂O, Cs₈Zr₄F₂(SO₄)₁₁ · 16H₂O, and Cs₂ZrF₄SO₄ offer the most efficient RL.     

Heat and Mass Transfer and Modeling and Prediction of Environmental Catastrophes

Basic definitions and concepts of the physicomathematical theory of natural catastrophes are given. Possibilities of mathematical modeling of natural and technogenic catastrophes are discussed in the context of the theory of heat and mass transfer and the mechanics of reacting media. The importance of taking into account conjugate heat and mass exchange in modeling catastrophes is emphasized. A formula for evaluating the probability of a collisional catastrophe is given.     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

Multi-ferroic and magnetoelectric materials and interfaces

The existence of multiple ferroic orders in the same material and the coupling between them have been known for decades. However, these phenomena have mostly remained the theoretical domain owing to the fact that in single-phase materials such couplings are rare and weak. This situation has changed dramatically recently for at least two reasons: first, advances in materials fabrication have made it possible to manufacture these materials in structures of lower dimensionality, such as thin films or wires, or in compound structures such as laminates and epitaxial-layered heterostructures. In these designed materials, new degrees of freedom are accessible in which the coupling between ferroic orders can be greatly enhanced. Second, the miniaturization trend in conventional electronics is approaching the limits beyond which the reduction of the electronic element is becoming more and more difficult. One way to continue the current trends in computer power and storage increase, without further size reduction, is to use multi-functional materials that would enable new device capabilities. Here, we review the field of multi-ferroic (MF) and magnetoelectric (ME) materials, putting the emphasis on electronic effects at ME interfaces and MF tunnel junctions.     

CellML and associated tools and techniques

We have, in the last few years, witnessed the development and availability of an ever increasing number of computer models that describe complex biological structures and processes. The multi-scale and multi-physics nature of these models makes their development particularly challenging, not only from a biological or biophysical viewpoint but also from a mathematical and computational perspective. In addition, the issue of sharing and reusing such models has proved to be particularly problematic, with the published models often lacking information that is required to accurately reproduce the published results. The International Union of Physiological Sciences Physiome Project was launched in 1997 with the aim of tackling the aforementioned issues by providing a framework for the modelling of the human body. As part of this initiative, the specifications of the CellML mark-up language were released in 2001. Now, more than 7 years later, the time has come to assess the situation, in particular with regard to the tools and techniques that are now available to the modelling community. Thus, after introducing CellML, we review and discuss existing editors, validators, online repository, code generators and simulation environments, as well as the CellML Application Program Interface. We also address possible future directions including the need for additional mark-up languages.     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.