Suspension characteristics and rheological properties of mullite/zirconia powder in methyl isobutyl ketone

Particle size and its distribution, sedimentation bulk density and rheology of mullite, zirconia, and mullite/zirconia mixed suspensions have been studied in terms of oxide loading (20, 30 vol%), and types of additives (dispersant, dispersant/plasticizer, dispersant/plasticizer/binder). Polyester/polyamine, dibutyl phthalate, poly(vinyl butyral), and methyl isobutyl ketone have been used as the dispersant, plasticizer, binder, and liquid medium, respectively. Sedimentation density significantly increased upon adding dispersant; the effect was more pronounced with zirconia suspension most likely due to the fine and hence high specific surface area of zirconia. With further addition of plasticizer and plasticizer/binder, the sedimentation density decreased. The suspension viscosity generally behaved in an opposite manner to the sedimentation density, i.e., low sedimentation density gave high low-shear viscosity, indicative of high order structure formation in the suspended particles. High shear rate rheology showed a shear thinning and its onset began at lower shear rate with higher solid loading. Mullite/zirconia mixed suspension gave intermediate sedimentation and rheological behavior, implying the two types of particles are non-interacting.     

Reflectionless absorption of superhigh-frequency radiation in solutions of methyl ethyl ketone and methyl isobutyl ketone in <Emphasis Type="Italic">n</Emphasis>-heptane

Investigations of dielectric properties of solutions of methyl ethyl ketone and methyl isobutyl ketone in n-heptane in a microwave range established the existence, in these solutions, of a spectrum of concentrations and thicknesses of the solution layer at which resonant reflectionless radiation absorption originates. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 1, pp. 173–177, January–February, 2007.     

Effects of acetone on methyl ethyl ketone peroxide runaway reaction

Runaway reactions by methyl ethyl ketone peroxide (MEKPO) are an important issue in Asia, due to its unstable structure and extensive heat release during upset situations. This study employed differential scanning calorimetry (DSC) to draw the experimental data for MEKPO 31 mass% and with acetone 99 mass% on three types of heating rate of 2, 4, and 10 degrees C/min; the kinetic and safety parameters were then evaluated via curve fitting. Through the reproducible tests in each condition, the results show that acetone is not a contaminant, because it could increase the activation energy (Ea) and onset temperature (To) when combined with MEKPO, which differs from the hazard information of the material safety data sheet (MSDS).     

甲乙酮肟封闭水性多异氰酸酯的合成及表征

利用甲苯二异氰酸酯(TDI)、三羟甲基丙烷(TMP)与二羟甲基丙酸(DMPA)反应,三乙胺(TEA)中和成盐及甲乙酮肟(MEKO)封端反应后,制得一种水分散性封闭多异氰酸酯(WBI)。研究了封闭时间对封闭率的影响,封闭顺序对反应的影响。采用FT-IR、TGA、DSC研究了其解封温度。实验结果表明,甲乙酮肟封闭反应的较好条件为:摩尔比n(MEKO)∶n(-NCO)为1.1～1.2;反应温度为70℃;反应时间3.0h,可实现较完全的封闭,其解封温度为70～128.8℃。作为涂料固化剂可明显改善漆膜性能。     

Study of thermal decomposition of methyl ethyl ketone peroxide using DSC and simulation

Methyl ethyl ketone peroxide (MEKPO) is a typical organic peroxide with thermally unstable nature that has been broadly employed in the manufacturing process of acrylic resins, as a hardening agent for fiberglass-reinforced plastics, and as a curing agent for unsaturated polyester resins. The aim of this study was to identify the characteristics of MEKPO 31 wt.% while mixing with contaminants, such as H(2)SO(4), HCl, and NaCl under runaway conditions. To acquire the thermal runaway data, DSC and a simulation were used for thermal analysis. The results showed that the thermal decomposition of MEKPO and MEKPO+H(2)SO(4) follows two stages. The first one can be modeled by using an empirical nth order rate equation. The second stage can be modeled as autocatalytic. MEKPO+HCl and MEKPO+NaCl included two independent autocatalytic reactions. The decomposition of MEKPO in the presence of Cl- ions (added in MEKPO either in the form of HCl or NaCl) follows a significantly different path, an earlier decomposition "onset" temperature, higher amount of generated thermal power and smaller temperature of no return (T(NR)) and time to maximum rate (TMR) values. Simulations based on experimental data indicated that the effect of H(2)SO(4) was the most dangerous contaminant on MEKPO 31 wt.%. However, the impact of Cl ions was also important. It is therefore recommended that the means of fire fighting employed for this substance to be free of Cl-.     

磺化杂萘联苯聚醚酮膜的制备及其阻醇和质子导电性能

采用浓硫酸和发烟硫酸的混合物作磺化剂得到不同磺化度的磺化杂萘联苯聚醚酮（SPPEK）,考察了不同磺化度的SPPEK膜的导电和阻醇特性．磺化度为73％的膜在测试的温度范围内膜的电导率数量级在10^-2S／cm,其甲醇透过系数约比Nafion 115膜低一个数量级,如果以质子传递通量和甲醇传递通量之比定义为综合指标,SPPEK膜的综合性能比Nafion 115膜高3．3倍。     

Preparation and characterization of poly (methyl methacrylate) and sulfonated poly (ether ether ketone) blend ultrafiltration membranes for protein separation applications

Poly (methyl methacrylate) (PMMA) and poly (methyl methacrylate)/sulfonated poly (ether ether ketone) (SPEEK) blend membranes were prepared by phase inversion technique in various composition using N,N'-dimethylformamide as solvent. The prepared membranes were characterized in terms of pure water flux, water content, porosity and thermal stability. The addition of SPEEK to the casting solution resulted in membranes with high pure water flux, water content, porosity and slightly low thermal stability. The cross sectional views of the blend membranes under electron microscope confirm the porosity and water flux results. The effect of the addition of SPEEK into the PMMA matrix on the extent of bovine serum albumin (BSA) separation was studied. It was found that the permeate flux increased significantly while the rejection of BSA from aqueous solution reduced moderately during ultrafiltration (UF) process. The effect was attributed to the increase in porosity and charge of the membrane due to the addition of SPEEK into the PMMA blend solution.     

Calorimetric studies on the thermal hazard of methyl ethyl ketone peroxide with incompatible substances

In Taiwan, Japan, and China, methyl ethyl ketone peroxide (MEKPO) has caused many severe thermal explosions owing to its thermal instability and reactivity originating from the complexity of its structure. This study focused on the incompatible features of MEKPO as detected by calorimetry. The thermal decomposition and runaway behaviors of MEKPO with about 10wt.% incompatibilities, such as H(2)SO(4), HCl, NaOH, KOH, FeCl(3), and FeSO(4), were analyzed by dynamic calorimeter, differential scanning calorimetry (DSC) and adiabatic calorimeter, vent sizing package 2 (VSP2). Thermokinetic data, such as onset temperature, heat of decomposition, adiabatic temperature rise, and self-heat rate, were obtained and assessed. Experimental data were used for determining the incompatibility rating on hazards. From the thermal curves of MEKPO with assumed incompatible substances detected by DSC, all the onset temperatures in the other tests occurring earlier advanced, especially with alkaline or ferric materials. In some tests, significant incompatible reactions were found. Adiabatic runaway behaviors for simulating the worst case scenario were performed by using VSP2. These calorimetric data led to the same results that the alkaline or ferric solution was the most incompatible with MEKPO.     

磺化聚芳醚酮酮的制备及磷酸硼复合膜的性能

通过亲核缩聚反应合成含二氮杂萘酮结构的磺化聚芳醚酮酮(SPPEKK),并经原位复合制备了磺化聚芳醚酮酮/磷酸硼(SPPEKK/BP04)复合质子交换膜.用核磁共振谱(1H-NMR)和FT-IR光谱表征纯膜及其复合膜结构,研究了BPO4的含量对复合膜的保水能力、热稳定性能、质子传导率以及复合膜中BPO4稳定性能的影响.结果表明,随着BPO4含量的增加,SPPEKK/BPO4的复合质子交换膜质子传导率逐渐增大.当BPO4含量达到30%时,质子传导率达到6.3×10-2S/cm(90℃).用原位生成法制备的SPPEKK/BPO4在保持一定尺寸稳定性和热稳定性的前提下,膜的导电性能明显改善.     

含二氮杂萘酮结构聚芳醚砜酮超滤膜的研制

以新型耐高温特种工程塑料———含二氮杂萘酮结构聚芳醚砜酮(PPESK)为膜材料、N-甲基-2-吡咯烷酮为溶剂配制铸膜液,采用相转化法在平板刮膜机上制备PPESK超滤膜,考察了PPESK含量、PPESK的特性黏数、添加剂含量和膜厚度等对超滤膜性能的影响.在0.1MPa的操作压力下,所制得PPESK超滤膜的纯水通量可高达约148L/(m2·h),对聚乙二醇10000的截留率高于93%.     

碳纤维-AlN/聚醚醚酮复合材料的制备与性能

以聚醚醚酮(PEEK)为基体树脂、碳纤维(CF)和氮化铝(AlN)为填料,通过模压成型的方法制备了抗静电耐热型CF-AlN/PEEK复合材料。采用高阻计、导热系数测定仪、热失重、差示扫描量热仪和SEM研究了CF-AlN/PEEK复合材料的抗静电性能、热性能、力学性能以及降温速率对复合材料性能的影响,并探讨了后期热处理对力学性能的影响。结果表明:当CF和AlN的质量分数均为10%时,CF-AlN/PEEK复合材料的性能较优,其表面电阻率达到108 Ω,比PEEK的表面电阻率提高了6个数量级;导热系数为0.418 W·(m·K)-1,初始分解温度高达573℃;拉伸强度提高了40.4%;降温速率越低,复合材料的熔点越高;后期热处理会影响CF-AlN/PEEK复合材料的力学性能,在270℃下热处理2 h,其拉伸强度可达146 MPa,表明在生产过程中,加工温度是影响复合材料性能的因素之一。      

Modeling of the emission rates of methyl ethyl ketone and effects of additives on the emission rate

Abstract

VOC(Volatile organic compound) emission rate was modelled in this study. The effects of the different environmental factors and the additives upon the emission rates were also determined. The study was conducted in a test chamber and in the field for determination of the emission rate of methyl ethyl ketone (MEK). Additionally, the theory of mass transfer was used to derive an MEK emission model with three variables (temperature, humidity, ventilation rate) and five coefficients (T ₁, R ₁, K_B , ACH_std and C_std ); these were determined by the results of emission rate in a test chamber. The emission rate of MEK ranged from 16.1 × 10³ to 101.0 × 10³ mg/m²/hr/(g‐MEK) for those cases which used solvents and plasticizer, and from 5.6×10³ to 58.1×10³ mg/m²/hr/(g‐MEK) when PVC powder was added. Additionally, the MEK emission rates increased with an increase in temperature, humidity, and ventilation rate. The mass transfer coefficients of MEK determined from the VOC emission model were approximately 0.00246 m/sec for those cases which used solvents and plasticizer, and decreased by a factor of 0.67 to 0.00164 m/sec for those cases which used solvents, plasticizer and PVC powder.     

Preparation of sulfonated poly (phthalazinone ether ketone ketone) and properties of the composite membranes SPPEKK/BPO4

通过亲核缩聚反应合成含二氮杂萘酮结构的磺化聚芳醚酮酮(SPPEKK), 并经原位复合制备了磺化聚芳醚酮酮/磷酸硼(SPPEKK/BPO₄)复合质子交换膜. 用核磁共振谱(¹H--NMR)和FT--IR光谱表征纯膜及其复合膜结构, 研究了BPO₄的含量对复合膜的保水能力、热稳定性能、质子传导率以及复合膜中BPO₄稳定性能的影响. 结果表明, 随着BPO₄含量的增加, SPPEKK/BPO₄的复合质子交换膜质子传导率逐渐增大. 当BPO₄含量达到30\%时, 质子传导率达到6.3 ×10^-2 S/cm(90℃). 用原位生成法制备的SPPEKK/BPO₄在保持一定尺寸稳定性和热稳定性的前提下, 膜的导电性能明显改善.     

Molecular simulation studies of adsorption of hydrogen cyanide and methyl ethyl ketone on zeolite NaX and activated carbon

In the present research study the primary aim is to understand and characterize the physical adsorption of polar molecules namely, hydrogen cyanide and methyl ethyl ketone (MEK) in zeolite NaX, and activated carbon through detailed Monte-Carlo simulations and computational quantum chemistry techniques. The sorption capacity and affinity of the zeolite is compared with activated carbon with different acid site concentrations, type of acid site, and pore sizes by simulating single component isotherms and Henry's constant at 25 degrees C. The role/contribution of certain types of electrostatic interactions namely charge-dipole, charge-induced dipole with zeolite NaX and activated carbon, as well as dipole-dipole interactions among polar molecules is analyzed and discussed.     

聚醚砜酮合金超滤膜的制备及表征

采用含二氮杂萘酮结构的磺化聚醚砜酮与聚醚砜酮共混的方法制备了一种新型荷电超滤膜.通过孔隙率、表面接触角、离子交换容量以及对达旦黄水溶液、聚乙二醇(PEG)6000水溶液分离性能的测试和扫描电镜对膜孔结构的观察,研究了合金膜中磺化聚醚砜酮含量对膜性能的影响规律.结果表明:当铸膜液中磺化聚醚砜酮含量从0增加到3%时,合金超滤膜水通量增大到491 L/(m2.h),对PEG6000的截留率可达86%.合金超滤膜具有高水通量、高截留率、亲水性好等特点.     

新型杂萘联苯聚醚砜酮中空纤维超滤膜的研制

以杂萘联苯聚醚砜酮(PPESK)为膜材料,N-甲基-2-吡咯烷酮(NMP)为溶剂,乙二醇甲醚(EGME)、丁酮和1,4-二氧六环为添加剂,采用干-湿相转化法制备了中空纤维膜.考察了聚合物浓度、添加剂种类、添加剂含量和干纺程对中空纤维超滤膜性能的影响.结果表明,当干纺程为15~20 mm时,聚合物浓度为19%~22%,添加剂为乙二醇甲醚时,中空纤维膜对PEG6000的截留率高于95%,纯水通量为100~120 L/(m2.h).