Polymer cosolvent system

Summary The preferential adsorption parameter of poly(phenyl methacrylate), poly[4-(1,1,3,3- tetramethylbutyl) phenyl methacrylate] and poly(4-tert-butyl styrene) in the mixture THF/water has been determined by exclusion chromatography (GPC) and differential refractometry and dialysis equilibrium (DR). The general behaviour of the polymers studied in this mixture is very similar, water is preferentially adsorbed by the polymer at low water content. The results are discussed in relation to the rigidity of the macromolecular chains and the hydrophobic degree of the substituent group in the aromatic ring.     

Polymer cosolvent systems

Summary In this paper we have studied the behaviour of PMMA in the binary mixture CCl₄/n-butyl chloride by viscometry, light scattering and dyalisis. We have found that the CCl₄/n-butyl chloride mixture behaves as cosolvent in the range 10 < u₂ < 90% n-butyl chloride. The n-butyl chloride is preferentially adsorbed in the whole composition range. The obtained results are discussed attending to G^E and the liquid order.     

甲醇体系中的氧气助溶剂研究

通过添加高溶氧溶剂的方法提升氧气在甲醇中的溶解度,探究了甲醇体系中的氧气助溶剂.考察分子结构、含氧基团及卤素原子对溶剂溶氧性能的影响,探究了氧气溶解的规律性,测试了几种氟代酯类溶剂的溶氧性能,并探究了助溶剂添加量对氧气溶解度的影响.结果表明:溶剂分子碳链越长,氧气溶解度越大;溶剂分子中含氧基团的存在可以增强溶剂与甲醇之...     

Preparation of asymmetric PVA membranes using ternary system composed of polymer and cosolvent

Integrally skinned PVA membranes have been prepared from PVA/NMP/water system by the phase inversion method in 2‐propanol bath, and the pervaporation characteristics of these membranes were investigated. With an increase in the NMP content in the polymer solution, the formation of skin layer depended on the NMP content in the cosolvent, and the overall morphology of membranes changed from porous to dense structure. Particularly, PVA membranes showed an asymmetric structure composed of a dense skin layer and a porous sublayer with finger‐like type and cellular structure in solvents of 50–60% NMP compositions. The experimental results from the pervaporation separation of MTBE and methanol mixtures were also in good agreement with the morphology for the formation of skin layer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2884–2890, 2003     

The fabrication of flexible and oxygen barrier cellulose nanofiber/polylactic acid nanocomposites using cosolvent system

The main disadvantages of polylactic acid (PLA) for food packaging applications are its brittleness and poor gas barrier properties. The purpose of this study is to evaluate the potential usability of triethyl citrate (TEC) and cellulose nanofiber (CNF) in PLA to obtain bio-based films with optimal properties. The incorporation of CNF as reinforcement fillers in polymer matrix has long been debated due to its difficulties to disperse uniformly in hydrophobic polymer matrix attribute to their hydrophobic nature. In order to overcome this problem, different feeding method for CNF into the mixer was studied, and CNF/PLA nanocomposites were characterized. It was found that CNF was successfully dispersed in the PLA matrix through the TEC-CNF suspension, which greatly improved tensile strength and flexibility of the CNF/PLA nanocomposites. The oxygen barrier property was enhanced up to 47.3% (16.99 cc·mm/m²·day·atm) with the increase loading of 0.25, 0.50, and 1 wt% of CNF. Moreover, the dynamic mechanical analysis showed that the low tan delta peak of CNF/PLA nanocomposites (48.25°C) was shifted to high peak (52.99°C) due to incorporation of TEC; indicates an improved of thermal stability of the composites. Overall, the t-CNF/PLA nanocomposites show a great feasibility for various eco-friendly flexible packaging applications.     

炔昧菊酯气雾剂助溶剂的对比研究

目的：研究解决炔咪菊酯农药在杀虫气雾剂中应用的助溶问题。方法：对炔咪菊酯农药在几种助溶剂中、料液中、成品中的溶解情况及其稳定性进行试验测试,对添加不同助溶剂后的产品进行药效检测。结果：用QMY作助溶剂,炔咪菊酯在助溶剂、料液以及成品中完全溶解,呈均成均相透明状,稳定性试验结果符合要求,药效不低于使用一般助溶剂。结论：QMY助溶剂性价比好,是一种值得推广的新助溶剂。     

Stereocomplex formation of PMMA in cosolvent mixtures

In this paper we have studied the stereocomplex formation of PMMA in the following cosolvent mixtures: $\text{acetronitrile}\text{CCI}{}_4$, acetonitrile/butyl chloride and butyl $\text{chloride}\text{CCI}{}_4$. We have found that, when the cosolvent power of the binary mixture increases, the complexing capacity decreases. These results can be explained by taking into account the excess Gibbs free energy, G^E, and the order of the liquids.     

高铁轨道板系统用高分子材料

以高分子材料制品的形式,综述了高速铁路轨道钢轨与基座间高分子材料的应用情况和技术发展方向,制品主要包括弹性垫板、Getzner减振板、轨下橡胶垫板、绝缘轨距块、尼龙预埋套管、CA砂浆等。     

活化液助溶剂对再生脱硝催化剂性能的影响

为了考察助溶剂对活化液的催化剂再生性能的影响,将某燃煤电厂失活退役的脱硝催化剂在相同清洗工艺下处理,随后分别浸入以草酸、乙醇胺作为助溶剂配制的活化液中,得到两个再生催化剂。采用XRF、氮气物理吸附法、原位吡啶吸附、NH₃-TPD、Raman、XPS、H₂-TPR以及固定床脱硝反应器等表征手段对新鲜样品、失活样品以及再生样品进行表面理化性质、脱硝性能测试评价。结果显示,脱硝催化剂失活的主要原因是飞灰中的碱金属K、Na造成催化剂的比表面积和孔容下降、表面Lewis酸性位数量减少、V⁵⁺比例下降、活性VO_x减少及氧化还原性能下降。同时发现,两个再生催化剂在等量活性组分钒条件下,脱硝性能却表现出较大差异,乙醇胺助溶活化液再生的样品Ethanol-cat性能恢复至新鲜催化剂的97%以上,而草酸助溶活化液再生的样品Oxalic-cat却几乎无再生效果,这是因为两种活化液中的活性组分钒状态不同,乙醇胺助溶活化液中钒离子可有效恢复失活催化剂的酸性位数量、V⁵⁺比例、活性物种VO_x     

Formation of giant protein vesicles by a lipid cosolvent method

This paper describes a method to create giant protein vesicles (GPVs) of ≥10 μm by solvent-driven fusion of large vesicles (0.1-0.2 μm) with reconstituted membrane proteins. We found that formation of GPVs proceeded from rotational mixing of protein-reconstituted large unilamellar vesicles (LUVs) with a lipid-containing solvent phase. We made GPVs by using n-decane and squalene as solvents, and applied generalized polarization (GP) imaging to monitor the polarity around the protein transmembrane region of aquaporins labeled with the polarity-sensitive probe Badan. Specifically, we created GPVs of spinach SoPIP2;1 and E. coli AqpZ aquaporins. Our findings show that hydrophobic interactions within the bilayer of formed GPVs are influenced not only by the solvent partitioning propensity, but also by lipid composition and membrane protein isoform.     

Low-temperature flow properties of vegetable oil/cosolvent blend diesel fuels

Vegetable oils are an attractive renewable source for alternative diesel fuels. However, the relatively high kinematic viscosity of vegetable oils must be reduced to make them more compatible with conventional compression-ignition engines and fuel systems. Cosolvent blending is a low-cost and easy-to-adapt technology that reduces viscosity by diluting the vegetable oil with a low-M.W. alcohol (methanol or ethanol). The cosolvent (A), which consists of one or more amphiphilic compounds, is added to solubilize the otherwise nearly immiscible oil-polar alcohol mixture. This work investigates cold flow properties and phase equilibrium behavior associated with blends consisting of soybean oil (SBO) and methanol where A=8∶1 (mol) n-butanol/oleyl alcohol; 6∶1 (mol) 2-octanol/triethylammonium linoleate; and 4∶1 (mol) 2-octanol/Unadol 40 (alcohols from SBO FA); and a blend of 2∶1 (vol/vol) No. 2 diesel fuel/SBO and 95% ethanol where A=n-butanol. Cloud point (CP), pour point, cold filter plugging point (CFPP), and low-temperature flow test (LTFT) results were compared with corresponding phase separation temperature (T _ϕ) data measured at equilibrium. Although CP data were measured under non-equilibrium experimental conditions, a nearly linear correlation was found between T _ϕ and CP. Statistical analysis showed that T _ϕ may also be correlated with CFPP and LTFT. Analysis of heating and cooling DSC curves indicated that peak temperatures may be employed to predict cold flow properties and T _ϕ behavior for SBO/cosolvent blends. Cooling curve parameters correlated more readily than heating curve parameters. Finally, relatively low quantities of heat evolved during freezing indicated that crystallization in the SBO/cosolvent blends studied in this work occurs easily during cooling.     

苯甲酸在含夹带剂的超临界CO2中溶解度的研究

采用流动法研究和测定了苯甲酸在35、50℃下,10.0—30.0MPa范围内,在纯超临界CO2和含醇系列夹带剂的超临界CO2中的溶解度。实验研究表明,醇系列夹带剂的加入均可明显增大苯甲酸的溶解度,但4种醇的增强作用随着碳链的增加而略有减弱。论述了温度、压力对溶解度的影响,并用Sovova方程对实验数据进行了回归。     

Precipitation polymerization of acrylic acid in compressed carbon dioxide–cosolvent systems

Precipitation polymerizations of acrylic acid (AA) in compressed carbon dioxide (65 bar) with different cosolvents, acetic acid, ethanol, and tetrahydrofuran, were studied. Analyses by viscosity measurement and differential scanning calorimetry indicate that the cosolvents have a pronounced effect on the properties of the product. Scanning electron microscopy shows that the products progress from microparticles to bicontinuous networks to fibers with the change of cosolvents and reaction conditions. Measurement of the volume expansion (ΔV%) of the liquid phase containing different cosolvents indicates that the miscibility of compressed CO₂ with the liquid phase is dependent on the cosolvent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1876–1880, 2003     

Structure formation and characterization of EVAL membranes with cosolvent of isopropanol and water

Microporous poly (ethylene-co-vinyl alcohol) (EVAL) membranes can be prepared by the solution casting method in combination of thermally induced phase separation (TIPS) with solvent evaporation. A cosolvent of isopropanol and water (3:2 w/w) is used to prepare the casting solution. EVAL membranes of different bulk or true densities, porosity, flexibility, crystallinity, and structure can be obtained by adjusting the casting temperature. A pseudo-binary temperature-concentration phase diagram of the EVAL-cosolvent system has been proposed, based on the information obtained from SEM, DSC, and light transmittance studies, to account for the membrane formation mechanism. The dense membranes were obtained when the casting temperature was higher than the upper critical solution temperature (UCST) of the system, but they might contain some nonSEM-observable micropores if the casting temperature was below the glass transition temperature (T_g) of EVAL. The porous and the least crystalline membranes with a honeycomb-like morphology were obtained through liquid-liquid demixing and vitrification at a casting temperature between the UCST and the dynamic crystallization temperature (T_c). Highly porous and crystalline membranes were obtained when they were prepared at temperatures near T_c. In this case, the particulate membranes were resulted from solid-liquid demixing mainly via TIPS, and membranes with leafy morphology were created through liquid-liquid demixing and then followed with immediately crystallization.     

助溶剂对铝合金表面硅烷化预处理的影响

为了了解3-缩水甘油醚丙基三甲氧基硅烷(γ-GPTMS)溶液中助溶剂对水解的γ-GPTMS在铝合金表面的沉积特性的影响,用X射线光电子衍射(XPS)测定了不同助溶剂含量,不同γ-GPTMS浓度的溶液沉积在铝合金表面的硅含量,同时用反射吸收红外光谱(RAIRS)对铝合金表面膜层进行了表征,结果表明,助溶剂对γ-GPTMS在铝合金表面沉积有显著影晌,γ-GPTMS的纯水溶液在铝合金表面所形成硅烷化膜层的硅元素量最高,沉积量随溶液中γ-GPTMS浓度的增加而增加。另外,膜层与氧化的铝合金表面之间形成铝硅氧烷(Al-O-Si)共价键,而且γ-GPTMS分子中的烷氧乙基分布在膜层的外表面,具有较大的反应活性。     

Lipase-catalyzed synthesis of lysophosphatidylcholine using organic cosolvent for in situ water activity control

Lysophosphatidylcholines (LPC) were synthesized from l-α-glycerophosphatidylcholine (GPC) by lipase-catalyzed esterification in a solvent-free system. Adding small amounts of a water-mimicking solvent such as dimethylformamide (DMF) to the reaction media significantly enhanced the reaction rate and the product yield. The role of solvent was studied with regard to changes in substrate solubility, the water activity of the reaction system, and the water content of the enzyme. Whereas the solubility of GPC was virtually unaffected by the addition of DMF at controlled water activity, it was considerably affected by water activity. DMF itself lowered the water activity of the system and deprived Lipozyme IM of water. The LPC production was also controlled by varying the initial water content of the enzyme. When two kinds of controls were employed together, a synergistic effect was observed and a 90% conversion was achieved. As a result, an operating window was suggested for LPC production, including water activity of Lipozyme IM and concentration of DMF as two parameters.     

浅谈环保型助溶剂丙二醇醚的现况与应用

简要介绍了丙二醇醚国内外现状以及丙二醇醚的环保性评价和用途。     

Polymer

<正> China Has a Robust Well Stimulation Materials Market China is one of the four major well stimulationmarkets to become commerciallysignificant.As recently as only a few yearsago,China accounted for only about fivepercent of the global market.This figure isroughly on par with its share of world oilproduction,in contrast with the US andCanada,which are much more prominent     

Polymer

<正> Tianye PVC Unit Comes on Stream Xinjiang Tianye (Group) Co Ltd (SH:600075) announced that its phase two 400 000 t/a polyvinyl chloride (PVC) unit started normal production on October 6th, bringing its total PVC capacity to 1.1 million t/a. The phase two project also includes a 300 000 t/a caustic soda unit, a 640 000 t/a calcium carbide unit, a 2 million t/a cement unit and a power