紫外光固化法合成St/AMPS/AM三元共聚高吸水性树脂

采用紫外固化法,以淀粉(St)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)为单体,N,N'-亚甲基双丙烯酰胺(NMBA)为交联剂,在不加引发剂和任何气氛保护下,合成出St/AMPS/AM/共聚高吸水性树脂,考察了反应条件对树脂吸水倍率的影响,并借助红外、偏光显微镜对树脂的分子结构及表面形态进行了表征。结果表明,在优化条件下合成的高吸水性树脂吸蒸馏水倍率为2354g/g,吸盐率可达145g/g(0.1mol/L)。     

二元共聚高吸水性树脂PAMA的吸液与保水性能

采用溶液聚合方法,以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(KPS)为引发剂合成了高吸水性树脂PAMA,并进行了吸液、保水性能研究。研究表明该树脂吸水倍率2451 g/g,吸生理盐水倍率119 g/g,对纯甲醇的吸液倍率(277 g/g);对吸液速率结果通过回归分析得吸蒸馏水时Qw=862.6t0.1855,吸生理盐水时Qs=52.0t0.1317。该吸水树脂具有优良的耐温保水性能和较好的热稳定性,且保水率与恒温时间呈线性关系,并能有效提高砂土的饱和含水量,可对砂土进行有效的改良。     

静置水溶液聚合法合成AA/AM/AMPS高吸水性树脂

以N,N'-亚甲基双丙烯酰胺(NMBA)和聚乙烯醇(PVA)为复合交联剂,通过静置水溶液聚合法制备了丙烯酸(AA)/丙烯酰胺(AM)/2-丙烯酰胺基-2-甲基丙磺酸(AMPS)共聚高吸水性树脂.探讨了反应条件对树脂吸水性能的影响,并通过FT-IR、SEM等技术对树脂的分子结构及表面形态进行了表征分析.实验结果表明:优化条件下所合成的树脂最高吸蒸馏水倍率为1641倍.以NMBA和PVA为复合交联剂,可以优化树脂的交联网络结构,且PVA在树脂中具有双重作用.     

耐盐性丙烯酸系吸水树脂的合成及吸液性能

在阶段式升温条件下．用溶液法合成了以丙烯酸(AA)、丙烯酰胺(AM)和2-丙烯酰胺-2-甲基丙磺(AMPS)为单体的三元高吸水树脂(SAP)，考察了单体摩尔配比、引发剂用量、交联剂用量、单体中和度对SAP在生理盐水和自来水中吸液倍率的影响，得到了合成三元SAP的较佳工艺条件；同时也研究了树脂在蒸馏水中的吸液速率及其在不同摩尔浓度的NaCl，NaBr，NaI溶液中的吸液倍率。     

微波辐射合成丙烯酸类耐盐性高吸水树脂及其性能

采用微波辐射方法合成了2-丙烯酰胺基-2-甲基丙磺酸(AMPS)/丙烯酰胺(AM)/丙烯酸(AA)耐盐性高吸水树脂。探讨了单体的组成、交联剂、引发剂用量、中和度和微波功率对待测液体吸液倍率的影响,并进行了树脂吸液速率和保水性能的研究,用红外光谱对树脂官能团进行了表征。实验结果表明,该树脂在蒸馏水中的吸水倍率为1509 g/g,在质量分数为0.9%的NaCl及相同离子强度的CaCl2、FeCl3溶液中吸液倍率分别为184g/g,165g/g,14g/g,树脂具有较强的耐盐性能;树脂的吸液倍率与电解质溶液阳离子的价态有关,价态越高,树脂的吸液倍率越低;该树脂具有较大的吸水速率和良好的保水性能。     

有机/无机复合高吸水树脂耐盐性和防潮性能研究

以过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,丙烯酸、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,聚乙烯醇为有机合成聚合物,硅藻土为无机黏土,采用水溶液聚合法合成有机/无机复合高吸水树脂。采用傅里叶变换红外光谱仪、扫描电子显微镜和热重分析仪对有机/无机复合高吸水树脂进行了表征,考察了引发剂用量、交联剂用量、AMPS用量及硅藻土用量对复合吸水树脂吸液性能的影响。在最佳反应条件下,有机/无机复合高吸水树脂吸蒸馏水倍率、吸0.9%生理盐水倍率分别为1574g/g和101g/g;纯有机高吸水树脂暴露在空气中的吸湿性是复合高吸水树脂的20～30倍,说明有机/无机复合高吸水树脂具有优异的防潮性能,在不同阳离子盐溶液中(Na~+、Ca~(2+)和Fe~(3+))其吸液性能明显优于纯有机高吸水树脂。     

三元共聚高吸水树脂的简易合成

在没有氮气保护和引发剂作用下,以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,采用静置热聚合法成功合成了2-丙烯酰胺基-2-甲基丙磺酸(AMPS)/丙烯酰胺(AM)/壳聚糖(CTS)三元共聚高吸水树脂。同时研究了反应条件对树脂吸水倍率的影响,并借助FT-IR对树脂的分子结构进行了分析。实验结果表明,所合成的树脂最佳反应条件为:n(AM)∶n(AMPS)=3∶1,ω(CTS)=2%,ω(NMBA)=0.05%,pH=1.5,固含量为15%。在此条件下合成的高吸水树脂室温下最大吸蒸馏水倍率为1302g/g。     

微波辐射凹凸棒接枝AMPS/AM高吸水树脂的制备和表征

以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(KPS)为引发剂,采用微波辐射方法制备了凹凸棒(APT)接枝2-丙烯酰胺基-2-甲基丙磺酸(AMPS)/丙烯酰胺(AM)耐盐性高吸水性树脂。探讨了单体配比、微波功率(P)、中和度(N)、APT用量、NMBA用量和KPS用量对待测液体吸水倍率的影响,用红外光谱(FT-IR)、X射线衍射(XRD)对高吸水性树脂进行了表征。实验结果表明,在最佳合成条件(n(AM)∶n(AMPS)=4.5∶1,P=390W,N=75%,w(NMBA)=0.08%,w(KPS)=0.6%,w(APT)=7.5%)下树脂在去离子水中的吸水倍率为1460 g/g,吸生理盐水倍率为114 g/g,树脂具有较强的耐盐性能;红外光谱(FT-IR)和X射线衍射(XRD)表征显示,凹凸棒和有机单体之间发生了接枝共聚反应,其反应仅在凹凸棒的表面进行,单体并没有插入到凹凸棒的层间。     

不同结构高吸水树脂的制备与性能研究

采用水溶液聚合法,以丙烯酸、丙烯酰胺和2-丙烯酰胺基-甲基丙磺酸为反应单体,制备了3种高吸水树脂聚丙烯酸-丙烯酰胺(P(AA-AM))、聚丙烯酸-2-丙烯酰胺基-甲基丙磺酸(P(AA-AMPS))和聚丙烯酸-丙烯酰胺-2-丙烯酰胺基-甲基丙磺酸(P(AA-AM-AMPS)),系统考察了反应条件对高吸水树脂吸水和吸盐水性能的影响,并研究了3种高吸水树脂在不同浓度的KCl、CaCl2和FeCl3中的吸水性能。结果表明:反应条件对不同高吸水树脂吸水性能的影响具有相同的趋势,但不同高吸水树脂的最佳反应条件不相同,P(AA-AM)、P(AA-AMPS)和P(AA-AMAMPS)的最佳反应条件分别为:中和度75%、65%和80%;交联剂用量都为单体总质量的0.02%;引发剂用量为单体总质量的0.20%、0.24%和0.20%;不同高吸水树脂受离子溶液的影响程度不同,P(AA-AM)CaCl2>KCl。     

静置法合成AMPS/AA/AM/MA四元共聚高吸水树脂

以N,N'-亚甲基双丙烯酰胺(NMBA)为交联剂,在没有引发剂和氮气保护的情况下,利用静置法制备以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)、丙烯酰胺(AM)、顺丁烯二酸酐(MA)为单体的四元共聚高吸水树脂,通过对反应条件优化,得到了最佳工艺条件:单体配比n(AMPS)∶n(AA)∶n(AM)∶n(MA)=1∶1∶1∶1,ω(NMBA)=0.03%,pH=2.2,在此条件下树脂吸蒸馏水倍率达到533倍。初步对树脂的吸液能力、耐热保水性、吸水速率、以及反复吸液性进行了研究,同时借助FT-IR、TG-DTG和显微镜对其结构、热稳定性及表面形态进行了表征。     

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.     

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.     

The shape and stability of wall-bound and wall-edge-bound drops and bubbles

The behavior of wall-bound drops and bubbles is fundamental to many natural and industrial processes. Key characteristics of such capillary systems include interface shape and stability for a variety of gravity levels and orientations. Significant solutions are in hand for axisymmetric pendent drops for a variety of uniform boundary conditions along the contact line with gravity acting normal to a planar wall. The special case of a wall-bound drop or bubble that is also pinned at an edge (i.e. a ‘wall-edge-bound’ drop) is considered here where numerical solutions are obtained for interface shape and stability as functions of drop volume, contact angle, fluid properties, and uniform gravity vector. For a semi-infinite zero-thickness planar wall (plate), a critical contact angle is identified below which wall-edge-bound drops are always stable. The critical contact angle is computed as a function of the gravity vector. The numerical procedure, which makes no account for contact angle hysteresis, predicts that such wall-edge-bound drops are unconditionally unstable for any gravity field with a component that is tangent to the wall while inwardly normal to the edge. Select experiments are conducted that support the conclusions drawn from the numerical results.