制备均匀分散铁红微粉的新方法

以ＦｅＳＯ４为原料，采用两步法液相氧化工艺制备了均匀α－Ｆｅ２Ｏ３微粉，研究了反应悬 浮液中Ｆｅ（Ⅱ）浓度及初ＰＨ值对γ－ＦｅＯＯＨ相转化的影响。结果表明，ＦｅⅡ浓度及ＰＨ值对γＦｅＯＯＨ－α－Ｆｅ２Ｏ３相转化时间有很大影响。在ＰＨ值近中性时，少量的Ｆｅ（Ⅱ）离子对相转化具有显著的催化作用，因而缩短了反应周期。通过改变生长与成核两阶段消耗ＦｅＳｏ４的比值，可方便地人为控制αＦｅ２Ｏ３的粒度。     

由硫酸钠废液制硫酸钾的研究

以氯化钾为原料从含有Ｎａ２ＳＯ４的废液中制得了符合国标要求的硫酸钾和氯化钠。利用Ｋ＋，Ｎａ＋∥Ｃｌ－，ＳＯ２－４——Ｈ２Ｏ四元水盐体系相图，拟定了无排泄物工艺流程。研究了物料配比、水量对中间产品钾芒硝、产品硫酸钾和副产品氯化钠的质量和得率的影响。     

聚丙烯酰胺对AS—C4H9OH—H2O体系相图的影响

本考察了含有和不含有无机盐时，ＰＡＭ和ＨＰＡＭ对ＡＳ－Ｃ４Ｈ９ＯＨ－Ｈ２Ｏ三元相图的影响。结果表明，ＡＳ－Ｃ４Ｈ９ＯＨ－Ｈ２Ｏ体系的相图中由两相区，液晶区，胶束区和乳状液区组成，ＰＡＭ的加入对体系相太怃明显影响，ＨＰＡＭ相对行为的影响与电解质类似，但其作用远小于电解质；ＮａＣｌ和ＣａＣｌ２的存在有利于液晶形成，且乳状液区面积明显增大，盐的浓度越大，反离子价数越高，乳状液区面积越大，无机盐－聚丙烯     

羟基及乙酰氧基封端聚砜低聚体的合成工艺研究

以双酚Ａ（ＢＰ－Ａ）和４，４’－二氯二苯砜（ＤＣＤＰＳ）为原料，合成了几种不同分子量的端羟基聚砜低聚体（ＯＨ－ＰＳＵ），并对其进行了乙酰化。对聚砜低聚体的合成工艺问题进行了较为深入的研究，重点就温度、原料配比、Ｋ２ＣＯ３对低聚体分子量的影响及溶剂对反应过程和结果的影响进行了讨论     

纺锤形γ—Fe2O3微小颗粒的形成

用ＦｅＳＯ４和Ｎａ２ＣＯ３为原料制备纺锤形γ－ＦｅＯＯＨ微小颗粒，用透射电镜和Ｘ射线衍射观察到纺锤形γ－ＦｅＯＯＨ微小颗粒的形成是丝状晶粒的聚集和生长的过程。研究了反应液的ＰＨ值和反应时反应气体压缩空气的流量变化对γ－ＦｅＯＯＨ微小颗粒形貌的影响，观察了由这种γ－ＦｅＯＯＨ制成的γ－ＦｅＯＯＨ制成的γ－Ｆｅ２Ｏ３的形貌，提出提高其磁性能的途径。     

纺锤形γ－Fe_2O_3微小颗粒的形成

用ＦｅＳＯ＿４和Ｎａ＿２ＣＯ＿３为原料制备纺锤形α－ＦｅＯＯＨ微小颗粒，用透射电镜和Ｘ射线衍射视察到纺锤形α－ＦｅＯＯＨ微小颗粒的形成是丝状晶粒的聚集和生长的过程，研究反应液的ｐＨ值和反应时压缩空气的流量变化对α－ＦｅＯＯＨ微小颗粒形貌的影响，观察了由这种α－ＦＥＯＯＨ制成的γ－Ｆｅ＿２Ｏ＿３的形貌，提出提高其磁性能的途径。     

涂敷型铬酸盐钝化膜的结构与耐蚀性

采用ＳＲＤ，ＥＤＸＡ，ＧＤＳ等方法研究了镀锌钢板表面涂敷型ＣｒＯ３－Ｈ３ＰＯ４－ＳｉＯ２系钝化膜的成分与结构。该钝化膜是一种由ＣｒＯ３，Ｃｒ（ＯＨ）３，ＣｒＯＯＨ，ＺｎＣｒＯ４，ＺｎＳｉＯ３，Ｚｎ３（ＰＯ４）２，ＣｒＰＯ４和ＳｉＯ２组成的凝胶网络状结构的涂敷型复合转化膜。探讨了其耐蚀机理，中性盐雾试验表明：该钝化膜的耐蚀性大大优于ＣｒＯ３－ＳｉＯ２系钝化膜。     

乙二酸钙酸解制乙二酸工艺研究

钙化法制乙二酸其主要反应是用硫酸酸解乙二酸钙的反应过程，通过实验确定ＳＯ２－４—Ｃａ２＋相图，从而找到ＣａＳＯ４·２Ｈ２Ｏ结晶成长区和自发成核区。用数学模型指导投料，能得到较理想结晶粒度，过滤速率高达０．７５ｍ３·ｍ－２·ｍｉｎ－１。     

利用粗镁生产精制一水酸镁的研究

根据ＭｇＳＯ４－Ｈ２Ｏ体系相图，提出了运城盐湖冬季大田结晶的粗硫酸镁生产精制一水硫酸镁的工艺流程，并对工艺条件进行了探讨和分析，最后指出该产品具有纯度高、呈中性、不含重金属杂质等优点。     

25℃和100℃时H3BO3—Na2SO4—NaCl—H2O体系的相平衡

测定了２５℃和１００℃时,Ｈ３ＢＯ３－Ｎａ２Ｓｏ４－ＮａＣｌ－Ｈ２Ｏ体系的固液平衡数据并绘成相图,应用相图分析了ＮａＣｌ作盐析剂分离Ｈ２Ｂ作盐析剂分离Ｈ３ＢＯ３的生产过程,为硼砂硫酸酸化制取Ｈ３ＢＯ３的生产工艺改进提供了一定的理论基础。     

Phase behavior of poly(N-isopropylacrylamide) in water-methanol cononsolvent mixtures and its relevance to membrane formation

The phase behavior of poly (N-isopropylacrylamide) (PNIPAAm) in solutions composed of water and methanol was studied at 25 °C. The pair of solvents used to dissolve PNIPAAm has been selected for the purpose to perform a cononsolvent system. From the observed phase behavior, PNIPAAm was soluble in either water or methanol individually but liquid-liquid demixing was observed in water/methanol mixtures. Flory-Huggins formalism including three binary interaction parameters and one ternary interaction parameter was used to analyze the phase behavior of the cononsolvent system. The mechanism of cononsolvency and its relation with the ternary interaction parameter were discussed. In addition, the use of two solvents serving as a cononsolvent system, replacing the traditional solvent-nonsolvent pair, for the membrane formation was investigated. Regardless of water or methanol being used as the solvent, it showed a rapidly precipitating system and macrovoid morphology due to liquid-liquid demixing was obtained. Trend expected on the basis of the phase diagram was in reasonable agreement with the observed membrane morphology. Therefore, the principles of membrane formation established for the ternary systems with nonsolvent-solvent-polymer can be extended to a cononsolvent-polymer system.     

MORPHOLOGY AND TRANSPORT STUDY OF PHASE INVERSION POLYSULFONE MEMBRANES

Two different types of polysulfone (PS) membranes were prepared by the phase inversion process utilizing water or isopropanol as nonsolvent. The Flory-Huggins theory for a ternary system nonsolvent/solvent/polymer is applied to describe the'thermodynamic equilibria of the components. The calculated ternary phase equilibria show that demixing of a PS binary solution with n-methylpyrrolidone (NMP) will be fast in a water coagulation bath and will be delayed in an isopropanol bath. The prepared membranes were characterized by SEM, gas adsorption-desorption technique, and permeability measurements. The membrane, which is precipitated by fast demixing in a water bath, has nodular structures in the skin region and includes finger-like cavities in the sublayer. The membrane coagulated by isopropanol has a very dense and thick skin structure, which is formed by delayed demixing. The membrane coagulated by isopropanol showed considerably lower pore volume and surface area compared to that observed with water coagulation method.     

相转化法聚合物/溶剂/非溶剂铸膜体系的热力学计算

计算了相转化法铸膜体系中常见的典型三元相图,分析了聚合物与溶剂之间、聚合物与非溶剂之间、溶剂与非溶剂之间的相互作用参数对聚合物/溶剂/非溶剂铸膜液体系相图的影响,以及体系温度和聚合物摩尔体积对聚合物/溶剂/非溶剂铸膜液体系相图的影响。根据溶剂-非溶剂汽液平衡数据和溶解度参数得到了溶剂-非溶剂、溶剂与聚合物以及非溶剂与聚合物之间的Flory-Huggins相互作用参数,从而获得了几种常见铸膜液体系的相图。同时,利用聚合物/溶剂/非溶剂铸膜液体系的相图数据对热力学模型的参数进行了优化,取得了与实验结果较一致的计算结果。     

Phase behavior of poly(ether imide) in mixtures of N-methyl-2-pyrrolidinone and methylene chloride

The phase behavior of poly(ether imide) (PEI) in solutions composed of N-methyl-2-pyrrolidone (NMP) and methylene chloride (MC) was studied at 25 °C. The pair of solvents used to dissolve PEI has been selected for the purpose to perform a cononsolvent system. From the observed phase behavior, PEI was soluble in either NMP or MC individually but liquid-liquid demixing was observed in mixtures of NMP and MC. However, no cononsolvency was found by the theoretical prediction on the basis of Flory-Huggins formalism including three binary interaction parameters. Therefore, attempts were made to correlate the phase behavior of a cononsolvent system with the modified Flory-Huggins theory using a ternary interaction parameter. A good prediction was obtained when a composition-dependent ternary interaction parameter was included into calculations. In addition, the mechanism of cononsolvency and its relation with the ternary interaction parameter in the cononsolvent systems were discussed. Based on the analysis of IR spectroscopy, the ternary interaction parameter correlates well with a more intermolecular complexation of NMP with MC in the presence of PEI. Thus, the driving force for cononsolvency results from the formation of the NMP-MC complexes favoring over NMP-MC-PEI contacts, leading to exclude PEI segments in the vicinity of the NMP-MC complexes.     

FORMATION OF SULPHURIC ACID AEROSOLS AND CLOUD CONDENSATION NUCLEI: AN EXPRESSION FOR SIGNIFICANT NUCLEATION AND MODEL COMPRARISON

A new analytical expression has been derived to predict atmospheric conditions where homogeneous water–sulphuric acid nucleation will have a significant effect on aerosol and cloud condensation nuclei population. In the expression, the condensational sink due to pre-existing aerosol particles and source due to chemical production of sulphuric acid have been taken into account. The analytical expression has been derived using a sectional aerosol dynamic model including nucleation, condensation, coagulation, deposition and sulphuric acid formation in the gas phase. In the present study we have also compared the sectional model with modal and monodisperse models. All models may be used for predicting the onset of significant new particle formation. However, the computationally more efficient models—monodisperse, modal, and sectional with low number of sections—over- or underpredict particle formation in some situations.     

Phase behavior of ternary polymer blends

The effect of varying interaction parameters on the phase diagrams of ternary polymer blends was explored by simulating spinodals through use of the Flory-Huggins lattice theory. Results indicate that miscibility is favored for the case of ternary mixtures of marginally miscible or marginally immiscible pairs where all pair interactions are nearly athermal. Miscibility is restricted for asymmetric ternary blends when one of the polymer pairs is either strongly miscible or strongly immiscible. For symmetric blends of partially immiscible pairs, both two-phase and three-phase miscibility gaps are predicted.     

MULTICOMPONENT POLYMER/SOLVENTS EQUILIBRIA: AN EVALUATION OF FLORY-HUGGINS THEORY FOR CROSSLINKED PDMS NETWORKS SWELLED BY BINARY MIXTURES

The prediction of equilibrium volume fractions of solvents mixtures in a polymer network is of utmost importance for processes dealing with polymeric materials (e.g. chromatographic and membrane processes). Up to now, few studies have studied the ability of existing theories to predict experimental multicomponent sorption data in polymers; this work intends to achieve that purpose on model liquid mixtures in contact with silicone rubber (polydimethylsiloxane). The equilibrium volume fractions of three liquid mixtures (chloroform/toluene; ethanol/toluene; ethanol/2-butanol) in crosslinked PDMS samples have been determined experimentally at 40^°C. Results are compared to predictions by the Flory-Huggins theory applied to ternary mixtures (one polymer and two liquids) with constant interaction parameters and negligible elastic contribution. Solvent/polymer interaction parameters have been determined by swelling the crosslinked samples in pure liquids, while liquid/liquid interaction parameters have been estimated from liquid/vapor equilibrium data. It is shown that the Flory-Huggins theory offers good predictions in the case of good (chloroform, toluene) and fair (2-butanol) PDMS solvents, while significant discrepancies are obtained with a non solvent (ethanol). Implications in ternary diagrams simulation and possible prediction improvements, based on non constant interaction parameters, are discussed.     

EXTRACTION OF NIOBIUM AND TANTALUM WITH BIS-2-ETHYLHEXYL ACETAMIDE

ABSTRACT The extraction of Nb and Ta from acid solutions with bis-2-ethylhexyl acetamide and the stripping of these metals with sulphuric acid solutions were investigated. The organic phase was a binary solution of bis-2-ethylhexyl acetamide and xylene, while the aqueous phase was composed of hydrofluoric acid solution or hydrofluoric-sulphuric acid solution containing 3.5-13 Kg/m³ Nb and 5-10 Kg/m³ Ta. Sulphuric acid, hydrofluoric acid and nitric acid were used as salting out agents to understand the effect on the extraction.

Niobium and tantalum were not sufficiently extracted from hydrofluoric acid solutions, whereas the extraction of both metals remarkably increased with an addition of sulphuric acid to the aqueous phase. Both metals were completely co-extracted under the aqueous condition of 6N hydrofluoric acid and 8N sulphuric acid. The stripping occurred for both metals with high efficiency when water or dilute sulphuric acid was used as a stripping agent. The increase in sulphuric acid concentrations caused less stripping of Ta, while the stripping of Nb was maintained at 80% up to 7N sulphuric acid.     

Sorption and diffusion measurements in ternary polymer-solvent-solvent systems by means of a magnetic suspension balance—Experimental methods and correlations with a modified Flory-Huggins and free-volume theory

Diffusion and sorption data of methanol and toluene in the ternary system methanol-toluene-poly(vinylacetate) (pvac) were measured by means of a magnetic suspension balance (MSB). Ternary diffusion coefficients were determined from sorption kinetics with a method of Crank [1975. The Mathematics of Diffusion, second ed. Claredon Press, Oxford] classically used for binary polymer solvent systems. Assumptions and limitations for this method are discussed. Sorption data of methanol and toluene in the ternary system were correlated with a modified Flory-Huggins theory taking four instead of three interaction parameters into account and compared with predictions of UNIFAC-FV. All four binary Flory-Huggins interaction parameters were correlated as a function of concentration, determined from binary polymer-solvent sorption measurements and from solvent-solvent equilibrium data. The modified Flory-Huggins approach for ternary systems predicts the two limiting cases for the binary polymer-solvent as well the two solvent-solvent equilibria. Diffusion coefficients determined from sorption kinetics measurements were correlated with free-volume theory predictions of Vrentas et al. [1984. Self diffusion in polymer-solvent-solvent systems. Journal of Polymer Science, Polymer Physics Edition, 22, 459-469] and compared with a few available literature data from Surana et al. [1998. Diffusion and equilibrium measurements in ternary polymer-solvent-solvent systems using inverse gas chromatography. Industrial and Engineering Chemistry Research, 37, 3203-3207]. Cross diffusion terms are not taken into account. Diffusion and sorption data, determined with this gravimetric method, were used in model simulations with modified Flory-Huggins and free-volume theory to predict drying curves of ternary methanol-toluene-pvac solutions. The results were compared with previously published experimental results performed by means of Inverse-Micro-Raman-Spectroscopy (IMRS) from Schabel [2004. Trocknung von Polymerfilmen - Messung von Konzentrationsprofilen mit der Inversen-Mikro-Raman-Spektroskopie. Ph.D. Thesis, Universität Karlsruhe (TH), Germany].     

三元链状分子系统液液平衡的Monte Carlo模拟和分子热力学模型

在格子模型基础上，采用构型偏倚蒸发法（CBVM）对三元链状分子系统的液液平衡进行了Monte Carlo模拟，分别考查了分子链长和链节间相互作用参数对相区的影响。模拟发现，在保持交换能参数一定的情况下，互溶区随高分子之一的链长的增加而减小。在各组分链长不变的情况下，分相区随交换能的减小而增加。修正的Freed模型（RFT）可较满意地再现模拟结果，而Ftory—Huggins模型总是过低地估计互溶区。RFT模型可满意地关联和预测苯-庚烷-二甘醇系统的二元和三元液-液平衡数据。