Studies on some properties of poly(phenylene sulphide)

Poly(phenylene sulphide) was synthesized by a direct method. Benzene and elemental sulphur were used as substrates, and aluminium chloride as a catalyst. The obtained final product was characterized by IR, VIS-UV, wide angle X-ray and mass spectroscopy, thermal, and elemental analyses. On the base of the analytical methods the molecular structure of the obtained polymer was discussed.     

Studies on the fungicidal properties of some triphenyltin(IV) compounds

The results are reported for an investigation into the fungicidal properties of six triphenyltin(IV) compounds representing metal coordination numbers of four through six. These experiments were conducted against a number of soil and plant pathogenic fungi and compared with the results obtained from triphenyltin chloride. While all the compounds examined proved to be effective fungicides, differences at the concentration levels tested were not sufficiently pronounced to relate the degree of toxicity to the molecular structure.     

Studies on preparation and properties of porous biodegradable poly(NIPAAm) hydrogels

A series of biodegradable porous hydrogels, based on thermosensitive N‐isopropylacrylamide (NIPAAm) and biodegradable crosslinker‐polycaprolactone diacrylate (PCLdA) that was synthesized from polycaprolactone diol with acryloyl chloride were prepared by photopolymerization at low temperature. The effect of the crosslinker content and gelation method on the swelling behaviors and physical properties for the poly(NIPAAm) hydrogels was investigated. Results showed that the swelling ratio of the gel in deionized water decreased with an increase of the content of polycaprolactone (PCL) segment in the poly(NIPAAm) hydrogels. The properties of the gels crosslinked with PCLdA were compared with those crosslinked with N, N′‐methylenebisacrylamide (NMBA). The results showed that the critical gel transition temperatures (CGTT) of the gels crosslinked with PCLdA were lower than those of the gels crosslinked with NMBA due to the hydrophobicity of the PCL segment. The results also showed that the gels crosslinked with PCLdA had higher mechanical strength and crosslinking density than those gels crosslinked with NMBA. Comparing the porous gels with nonporous gels, the results showed that the swelling ratio and CGTT of the porous gels were higher than those of the nonporous gels, and the transition temperature curve was smoother for the porous gels. The porous gels also exhibited more rapid thermal response and faster degradation rates. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Separation of Molybdenum(VI) and Tungsten(VI) through a Supported Liquid Membrane Impregnated with Trioctylmethylammonium Chloride

Abstract

Transport separation of molybdenum(VI) through a supported liquid membrane (SLM) was investigated by employing trioctylmethylammonium chloride (TOMAC) as a mobile carrier. The transport behavior of Mo(VI) and W(VI) was greatly dependent on hydrochloric acid and chloride ion concentrations in the feed solution. Molybdenum(VI) was effectively transported together with W(VI) from dilute HCl solutions in the presence of 0.1 M tartaric acid into NaOH stripping solutions. Molybdenum(VI) in high HCl concentration was transported in preference to W(VI). Addition of NaCl to the feed solution reduced the W(VI) transport, and this enhanced the separation of Mo(VI) from W(VI). Lower TOMAC concentration in SLM was favorable for the separation of the two metal ions, and a separation factor (α_Mo/W) of 46 was obtained with 0.1 M TOMAC-SLM.     

Carrier-Mediated Transport of Molybdenum(VI) through Supported Liquid Membranes

Abstract

The liquid membrane transport of Mo(VI) from an acidic solution into an alkaline stripping solution was carried out by using a mobile carrier, 5,8-diethyl-7-hydroxy-dodecan-6-one oxime (LIX 63). Further transport of MoO₄ ^2? from the alkaline solution was performed by using another carrier, trioctylmethylammonium chloride (TOMAC). Molybdenum(VI) was effectively transported through double membranes composed of LIX 63/dilute NaOH solution/TOMAC from a feed solution (10^?3 M HNO₃) into a product solution (1 M NaOH). Molybdenum(VI) was concentrated with high recovery into a small volume of product solution. The separation of Mo(VI) from several ions was performed by means of the double membranes.     

高铁酸盐制备方法研究进展

高铁酸盐是一种环境友好的强氧化剂,在水处理、有机合成和超铁电池等方面具有重要的潜在应用价值.综述了近20 a高铁酸盐主要合成方法的研究进展及其特点,包括:熔融法、次氯酸盐氧化法和电化学氧化法,其中电化学氧化法又包括液态高铁酸盐电合成法和固态高铁酸盐直接电合成法.指出:高铁酸钾直接电合成法以其操作简单、原材料消耗少、成本低、可循环生产、工艺绿色环保等优点而成为最有可能工业化应用的合成方法,同时指出了其发展方向.     

聚(甲基丙烯酸/丙烯酰胺)pH敏感微球的制备及性能的研究

以单体丙烯酰胺(AM)、甲基丙烯酸(MAA)为原料,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,偶氮二异丁腈(AIBN)为引发剂,在无水乙醇溶液中,60℃时通过沉淀聚合的方法制备出一系列的聚甲基丙烯酸/丙烯酰P(MAA/AM)微球。实验结果表明,成功的制备700～1 100 nm粒径范围内的单分散的微球;初步实现了对单分散的微球粒径大小及分布情况的控制设计。此外,微球具有良好的pH敏感性,此性能与MAA的解离常数有关;通过对环境pH值的调节可以迅速控制微球自身体积的收缩与溶胀。     

Kinetics of Molybdenum(VI) Oxide Dissolution in Sulfuric Acid Solutions

The kinetics of molybdenum(VI) oxide dissolution in sulfuric acid solutions at various temperatures is experimentally studied. A dissolution mechanism is proposed, and the kinetic parameters of dissolution are calculated.     

Poly(ester amide)-polyether block copolymers: preparation and some physcochemical properties

A series of elastoplastic copolymers formed of poly(ester amides) and poly(tetramethylenether glycol) segments were synthesized. Some physicochemical properties such as density, melting point, crystallinity and fusion enthalpy were determined. The influence of the structure on the properties is discussed in view of the sequence distribution statistics for finite chain length. The role of molecular weight is specified.     

Studies of adsorption properties of crosslinked chitosan for vanadium(V), tungsten(VI)

In this article, the adsorption properties of crosslinked chitosan (CCTS) for V(V) and W(VI) were studied. Experimental results showed the adsorption rates of CCTS for V(V) and W(VI) were closely related to the acidity of solution. The adsorption rates were 97% for V(V) at pH 4.0 and 96% for W(VI) at pH 4.5. The adsorption balance times, adsorption capacities, and adsorption mechanism were explored. This research is of significance for removal of V(V) and W(VI) in industrial wastewater and their preconcentration in trace analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1584–1588, 2004     

Comparison Between the Cr(VI) Adsorption by Hydrotalcite and Hydrotalcite-Gibbsite Compounds

Cr(VI) adsorption from aqueous solutions on Mg-Al hydrotalcite and Mg-Al hydrotalcite-gibbsite with Al/(Al+Mg) ratios (R) of 0.3 and 0.6 (MgAlHT_{R = 0.3} and MgAlHTG_{R = 0.6}) was investigated as a function of the pH and chromium concentration. The results showed that the maximum Cr(VI) adsorption by Mg-Al compounds do not depend on the value of R at pH 7. In addition, the chromate equilibrium sorption capacity for MgAlHTG_{R = 0.6} is at least 4.8 times higher than that for MgAlHT_{R = 0.3} at pH 5. The Cr(VI) maximum capacities of MgAlHT_{R = 0.3} and MgAlHTG_{R = 0.6} at pH 7 were similar, 6.5 and 6.8 mgCr(VI)/g, respectively.     

pH敏感聚合物微球的制备及其性能研究

通过原位聚合的方法制备了生物相容的、具有环境响应特性核壳型羟乙基纤维素／聚甲基丙烯酸(HEC／PMAA)聚合物微球。采用动态光散射法和荧光光谱法研究了HEC／PMAA聚合物微球的形成机理;采用红外光谱(FTIR)分析了微球中分子间相互作用;利用TEM观察了HEC／PMAA微球的形貌;考察了HEC／PMAA微球的pH敏感性能。     

Studies on the effects of some additives on the physicomechanical properties of urea-ammonium sulphate (UAS) pellets

The effects of some additives on the process of pressing mixed fertilizer based on Urea and Ammonium Sulphate (UAS) at a ratio of 4:1 and their impact on the kinetics of solubility were investigated. UAS pellets were produced using a laboratory pressing machine at an optimum pressure. Most of the inorganic salts with hydrated water gave better crushing strength and lower rates of dissolution as compared with UAS pellets without additives. The organic compound tall pech - a by-product of pulp production - acts as a better binding agent for UAS pellets in respect of both strength and solubility. It is assumed that except for hydrated inorganic salts the tall pech possesses the property of being a slow-release binder in the mixed UAS fertilizer.     

Speciation of Molybdenum (VI) In Aqueous and Organic Phases of Selected Extraction Systems

Abstract

The extraction study of molybdenum (VI) by 30% tri-n-butyl phosphate in n-dodecane and 0.2 M octyl (phenyl)-N,N-di-isobutylcarbamoylmethylphosphine oxide in 30% tri-n-butyl phosphate extraction systems was performed from aqueous solution containing HCl, HNO₃ and acetohydroxamic acid. Depending on extraction conditions, acetohydroxamic acid can significantly affect the speciation of molybdenum and can increase or decrease its distribution ratio. Our investigation confirmed the strong ability of the acetohydroxamic acid to form complexes with Mo even in highly acidic solutions. UV absorption spectra confirmed that a fraction of the Mo(VI)-AHA species can be present in the organic phase after extraction.     

Poly(mono n-alkyl itaconic acid esters): Their preparation and some physical properties

A series of poly(mono n-alkyl itaconic acid esters), with ester chain lengths varying from methyl to decyl, were prepared by emulsion polymerisation. The materials are all hard brittle glassy polymers at ambient temperatures and undergo a dehydration reaction in the range 430 K to 450 K. Dynamic mechanical measurements showed the presence of at least three other damping maxima: an Δ-transition at 90?95 K, a δ-transition at 190–200 K and a γ-transition at 240–260 K. The ε is associated with motion in the hydrocarbon part of the side chain, while the δ and γ transitions are associated with relaxations involving the carboxyl and alkoxycarbonyl groups respectively. Glass transitions were only detectable in higher esters. The thermal stability of the polymers is also briefly discussed.     

Studies of electrical properties of some fire-retarding poly(vinyl chloride) compositions

Several fire-resistant formulations were prepared from a sample of poly(vinyl chloride) (PVC), small variable proportions of chloroorganic adducts [1,2,3,4,7,7-hexachloro-5-carboxy,bicyclo(2,2,1)heptene-2] or [1,2,3,4,7,7-hexachloro-5-carboxy,5-methyl-bicyclo(2,2,1)heptene-2] as fire-retarding modifiers, plasticizers (dibutylphthalate and a chlorinated paraffin), and a heat stabilizer (dibutyltindilaurate). The fire-resistance and electrical properties of the obtained formulations were studied to obtain a fire-retarding plasticized PVC of good electrical insulation character. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 27–35, 1997     

Studies on the removal of Cr(VI) from waste-water by feldspar

The efficacy of feldspar in the removal of Cr(VI) from representative waste-water from a plating industry has been investigated in a completely mixed batch reactor at different concentrations, rate of agitation and particle size. The data obey the Langmuir isotherm for the present system and the process of uptake follows first-order kinetics. The maximum removal (91%) was observed at 40°C and pH 2.5 with initial concentration of 19.23 μmol dm^?3 Cr(VI) and 40 g dm^?3 feldspar. The process involves both film and pore diffusion to different extents. Column studies have also been carried out using a certain concentration of waste-water. More than 92% recovery has been achieved and the column can be used for 10 cycles before regeneration. The present technique seems to be quite attractive.     

Studies on the preparation and properties of inorganic molecularly imprinted polymer (MIP) based on tetraethoxysilane and silane coupling agents

Inorganic molecularly imprinted polymer (MIP) based on tetraethoxysilane (TEOS), methyl triethoxysilane (MTEOS), and phenyl triethoxysilane (PTEOS) by sol‐gel process has been developed. The MIP's preparation conditions, H₂O/Si molar ratios (R), template removal procedures, calcination temperatures, and quantity of ammonium hydroxide were investigated. The competition experiments of the MIP for template (caffeine, CAF) and analogue (theophylline, TH) were analyzed by high‐performance liquid chromatography (HPLC). The results showed that the Ad_CAF decreased with an increase of the H₂O/Si molar ratios, but the selectivity (α) increased with an increase of the H₂O/Si molar ratios in the MIP. In addition, in a comparison of the procedures for removing the template, calcination obtained better efficiency and higher selectivity than extraction. The optimum adsorption and selectivity of MIP were obtained with R = 10 and the template was removed by calcination at 600°C. Moreover, the selectivity of the MIP (283.9) was greater than the nonimprinted polymer (2.45) under optimum preparation conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Molybdenum(VI) Amino Triphenolate Complexes as Catalysts for Sulfoxidation,Epoxidation and Haloperoxidation

Two molybdenum(VI) complexes bearing a C₃ symmetrical amino tris‐tert‐butylphenolate ligand have proved to be air‐ and water‐tolerant catalysts that efficiently catalyse, in high yields and selectivity, the oxidation of sulfides, olefins and halides. In particular high turnover frequencies and turnover numbers (TOF and TON) have been obtained for the cyclooctene epoxidation (catalyst loading down to 0.05%, TONs up to 88,000 and TOFs up to 7500 h⁻¹).