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.     

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。     

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).     

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-.     

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.     

含联苯聚芳醚砜醚酮酮无规共聚物的合成与表征

以新合成的含联苯芳醚单体4,4'-二(4-联苯氧基)二苯砜(BBPOPS)与4,4'-二-苯氧基二苯砜(DPODPS)、对苯二甲酰氯(TPC)为单体,以路易斯酸无水三氯化铝(AlCl3)为催化剂进行三元共缩聚,制备了大分子主链含联苯结构的聚芳醚砜醚酮酮(PESEKK)无规共聚物.通过核磁共振仪、红外光谱仪、差示扫描量热...     

含1,4-萘基氯化聚芳醚酮酮无规共聚物的合成与性能

以无水AlCl3为催化剂、ClCH2CH2Cl和NMP(N,N-二甲基吡咯烷酮)为复合溶剂,由二苯醚(DPE),2,5-二氯对苯二甲酰氯(DCTPC)和4,4′-二(α-萘氧基)二苯酮(DNBP)通过亲电缩聚反应合成了一系列新型主链含1,4-亚萘基结构的氯化聚芳醚酮酮无规共聚物.优化后的工艺条件为:n(AlCl3)∶n(DCTPC)∶n(DNBP DPE)=0.06∶0.01∶0.01,预聚合温度小于-10℃下反应2h,再逐渐升温至25℃左右反应约8h.研究了DNBP结构单元及含氯侧基对共聚物性能的影响,并用IR、DSC、TG、WAXD等方法对其进行了表征.结果表明,所得聚合物在193～212℃的温度范围内均只出现一个玻璃化温度(Tg)转变峰,且随着共聚物中DNBP结构单元含量的增加,其Tg逐渐升高,而熔融温度(Tm)和结晶度逐渐降低.同时由于芳环上氯取代基的影响,降低了共聚物的热分解温度(Td),但仍具有良好的耐热性并且明显提高了阻燃性能和溶解性能.当x(DNBP)<30%时,共聚物仍为半结晶性,并选择n(DNBP)∶n(DPE)在10∶90～30∶70范围内为理想的聚合物加工成型条件.共聚物的断裂伸长率随着DNBP结构单元的引入逐渐增加,而拉伸强度和拉伸模量却有所下降.该类共聚物的拉伸强度可达78MPa以上,拉伸模量在2.8GPa以上,仍具有良好的力学性能.     

磺化杂萘联苯聚醚酮酮质子交换膜材料的合成与性能

以4-(4-羟基苯基)-2,3-二氮杂萘-1-酮(DHPZ)、1,4-二(3-磺酸钠基-4-氟代苯甲酰基)苯(SBFBB)和1,4-二(4-氯代苯甲酰基)苯(BCBB)为原料,经高温溶液缩聚反应,成功制备了一系列不同磺化度的新型杂萘联苯聚醚酮酮(SPPEKKs).利用FT-IR和1H-NMR对聚合物结构进行表征.采用溶液浇铸法制备了聚合物薄膜.测定了膜的吸水率,溶胀率,离子交换容量,耐氧化性和质子传导率.结果表明该系列磺化杂萘联苯聚醚酮酮膜具有良好的抗氧化性和较高的质子传导率.     

含氰侧基联苯型聚芳醚醚酮酮/芳醚醚酮酮共聚物的合成与表征

在无水AlCl3及N-甲基吡咯烷酮(NMP)/1,2-二氯乙烷(DCE)复合溶剂的存在下,将2,6-二苯氧基苯甲腈(DPOBN)与4,4’-二氯甲酰基联苯(BClBP)及对苯二甲酰氯(TPC)进行三元低温共缩聚反应,合成了一系列含氰侧基联苯型聚芳醚醚酮酮/芳醚醚酮酮共聚物。用IR、DSC、TG、WAXD及元素分析等方法对其结构和性能进行了表征。结果表明,所合成的聚合物具有预期结构且均为非晶态聚合物;其玻璃化转变温(Tg)度为180~196℃,在N2气氛中热分解5%的温度(Td)为495~508℃,具有突出的耐高温性能。     

聚芳硫醚酮酰胺树脂的合成与表征

通过合成4,4'-二苯基硫醚二甲酰氯(TDC),将其与4,4-'(对胺基笨基硫醚)二苯甲酮(BAPK)进行低温溶液缩聚,制备了聚芳硫醚酮酰胺(PASKA),通过红外、核磁、元素分析证实了其化学结构;采用DSC,TGA等手段对PASKA的热性能进行了表征,结果表明PASKA具有优良的热性能,同时表明它为无定形聚合物;溶解...     

共聚物聚苯硫醚-聚苯硫醚酮的合成及表征

在聚苯硫醚(PPS)的合成体系中加入不同比例的第三单体4,4二氯二苯甲酮(DCBP)从而合成了共聚物PP/SK.主要通过加入不同量的DCBP来考察产品的熔点及分子量的变化.合成工艺条件:前期反应的最高温度为T1=190℃～230℃,反应时间为t1=3h～5h;后期的反应温度最高为T2=250℃～270℃,反应时间为t2=2h～4h.n(Na2S·9H2O):n(对二氯苯/4,4二氯二苯甲酮)=1.1mol:1mol,m(N甲基吡咯烷酮):n(Na2S·9H2O)=282g:0.1mol,m(催化剂):n(Na2S·9H2O) =2g:0.1mol.根据上述加料及反应条件合成了线性的高分子量的共聚物PPS/SK,其重均分子量接近55000g/mol,产品的平均收率达到91.32％.通过一步循环回收工艺就实现了溶剂和催化剂的循环.用红外、元素分析、X-RD及热分析对产品进行了表征.     

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.     

新型含氰侧基氯取代聚芳醚醚酮酮的合成及表征

在无水AlCl3及N-甲基吡咯烷酮(NMP)/1,2-二氯乙烷(DCE)复合溶剂的存在下,将2,6-二苯氧基苯甲腈(DPOBN)与2,5-二氯对苯二甲酰氯(DCC)进行低温缩聚反应,合成了一类新型含氰侧基氯取代的聚芳醚醚酮酮.用IR、DSC、TG、WAXD等方法对其结构和性能进行了表征.结果表明,所合成的聚合物为非晶态聚合物;其玻璃化转变温度(Tg)为229℃,热分解5%的温度(Td)为445℃,说明其具有突出的耐高温性能;聚合物能在NMP、DMF、DMSO等强极性非质子溶剂及DCE、THF、CHCl3等普通溶剂中溶解或溶胀.     

Sulphonated poly(ether ether ketone): Synthesis and characterisation

The sulphonation of commercially available PEEK in powder form (Gatone, Gharda Chemicals Limited, India) was carried out using conc. H²SO⁴ under different reaction conditions. The duration of reaction was varied from 3–5 h, polymer concentration 4–10% (w/v) and temperature 35–50C. Structural characterisation of sulphonated polymers was done by elemental analysis, FT-IR and ¹H-NMR spectroscopy. The degree of sulphonation as calculated from ¹H-NMR and elemental analysis (S-content) was found to be in the range of 50–80%. Multistep mass loss was observed in thermogravimetric traces (recorded in N² atmosphere). The first step (50–225 ± 25C) was due to loss of moisture (1–10%) and second step (250–425 ± 25C) has been attributed to volatilization of SO³ from the sulphonic group. The backbone degradation takes place above 450C. The mechanical properties and proton conductivities of various sulphonated samples was also evaluated.     

Synthesis of Poly(ether ether ketone)s containing tertiary amine

A functional or reactive PEEK-Poly(ether ether ketone)s containing tertiary amine was synthesized. The product was determined by ¹H NMR, ¹³C NMR, IR spectra and elemental analysis. Thermal analysis of the polymer revealed the glass-transition temperatures (T_g = 119.57 °C), a 5% weight loss in air at 386 °C. An M_n of 10.4 kD, M_w of 20.2 kD, Polydispersity of 1.95 was obtained from GPC. The Poly(ether ether ketone)s containing a tertiary amine structure can be synthesized as a scaffolds for post-polymerization reaction.     

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.     

含有叔胺结构的聚醚醚酮单体的合成

通过三步反应合成了一种具有叔胺结构的聚醚醚酮单体,其结构经1H NMR1、3CNMR、IR和元素分析确证,同时讨论了影响反应的因素。