Physical Properties of Triglycerides III: Ultrasonic Sound Velocity

The ultrasonic sound velocity has been measured at 20° C and at 40° C for a number of triglycerides in the liquid state. From these data we have computed molar sound velocities according to Rao. Using published data on fatty acid methyl esters and a previously derived relation for triglycerides, an equation is given which relates the ultrasonic sound velocity of a mixture of triglycerides to its refractive index, density, and iodine value. The applicability of this relation to fatty oils is checked against a number of original fatty oils.     

Physical properties of fatty acid methyl esters. I. density and molar volume

Saturated fatty acid methyl esters from acetate to arachidate, methyl oleate, linoleate, linolenate, and erucate have been prepared in high purity. Densities, refractive indices, dispersions, ultrasonic sound velocities, and dielectric constants have been measured in the liquid state at 20 and 40C. In this first communication, the densities of the saturated compounds have been correlated with the Smittenberg relation. The following relations were derived: d ₂₀ ⁴ = 0.85407 + 0.18494/ (n + 0.096) and d ₄₀ ⁴ = 0.84225 + 0.12904/(n-0.408). Molar volumes have been computed and checked for additivity.     

Physical properties of fatty acid methyl esters. II. Refractive index and molar refraction

The refractive indices of methyl oleate, linoleate, linolenate, erucate, and the saturated fatty acid methyl esters from acetate to nonadecanoate have been measured at 20C and 40C for the Na_d, H _α , H _β , H _γ lines. The values for the saturated series have been correlated with the Smittenberg relation. Molar refractions have been computed and checked for additivity. The limiting refractive indices obtained from the Smittenberg relation are compared to those obtained from the molar refraction.     

Acoustic analysis of composite soft materials. I. Characterization of the core and boundary layer from compressibility of core/shell particles dispersed in poly(vinyl chloride)

The sound velocity of butyl acrylate rubber particles modified by poly(methyl methacrylate) in poly(vinyl chloride) was measured as a function of particle concentration. A model for estimating the adiabatic compressibility of the particle and the boundary layer was proposed. From the model, the partial specific adiabatic compressibility of the particles and the rubber core were evaluated. The adiabatic compressibility of the rubber core was estimated as 3.82 × 10⁻¹⁰ Pa⁻¹. The adiabatic compressibility of the poly(methyl methacrylate) shell is discussed based on the modified model. The study indicates that the shell, including the boundary layer between butyl rubber and poly(methyl methacrylate), is perturbed by the butyl acrylate molecules and is so soft as to be comparable to the rubber. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2089–2094, 2001     

Properties of positive resists. I. irradiation-induced degradation and sensitivity of certain methyl methacrylate copolymers

Poly(methyl methacrylate), poly(methyl methacrylate-co-2-hydroxyethyl methacrylate), poly(methyl methacrylate-co-itaconic acid), poly(methyl methacrylate-co-maleic anhydride), poly(methacrylic acid-co-itaconic acid), poly(methacrylic acid-co-maleic anhydride), and poly(itaconic acid) were prepared by copolymerization of the appropriate amounts of the two monomers at 50°C for 24–40 h using benzoyl peroxide as initiator. Selected samples were γ-irradiated with a total dose ranging from 2 to 12 Mrad. The unexposed and degraded polymers were dissolved in tetrahydrofuran and their molecular weight distribution was determined by gel permeation chromatography. It was found that M?_n decreased drastically with increasing irradiation dose. The presence of various functional groups in both unexposed and irradiated samples was confirmed by infrared spectroscopy. The copolymer thermodynamic compatibility with various solvents was evaluated on the basis of their fractional solubility parameters. The G_s values of these copolymers were determined using the gel permeation chromatography data. It was established that, among those studied, poly(methyl methacrylate-co-maleic anhydride) is the best material for positive resist application based on a G_s value of 8 9 scissions per 100eV.     

Some physicochemical properties of methyl methacrylate-grafted nylon 6. II.

Graft copolymerization of methyl methacrylate on nylon 6 was investigated using KMnO₄ as initiator at 60°C. The optimum conditions of the grafting process using various amounts of methyl methacrylate have been utilized. Physical and chemical properties of the grafted nylon such as moisture regain, density, and infrared spectra are studied. Furthermore, the dyeing behavior of the grafted nylon toward acid and direct dyes is also investigated. The rate of graft copolymerization (R_p) of methyl methacrylate with this system was evaluated and expressed by the following equation depending upon the potassium permanganate concentration used: The degree of polymerization of isolated poly(methyl methacrylate) from the grafted nylon was found to be a first-order dependence.     

Flow characteristics in an acoustic bubbling fluidized bed at high temperature

The pressure fluctuation of the quartz sand and SiO₂ particles was investigated using pressure transducer in high temperature fluidized bed with sound assistance. The effects of bed temperature, sound wave frequency, and sound pressure level (SPL) on the pressure fluctuation were examined. It indicates that the minimum fluidization velocity decreases with an increase in sound pressure level at the same sound frequency. At the same SPL and bed temperature, there always exists an optimal frequency range achieving good fluidization quality. As the sound frequency increases, the minimum fluidization velocity decreases firstly and then increases. Based on the statistical analysis of pressure signals, the effect of sound frequency on the fluidization quality at high-temperature fluidized bed was presented. On basis of discrete wavelet transform, an original signal was resolved into five-detailed scale signal. Furthermore, the peak frequency for Scale 3 detail signal represents the bubbling frequency.     

Procedure for calibrating an ultrasonic sensor for online monitoring of conversion in latex reactors

In order to estimate online conversion and polymer composition through sound velocity measurements, a mathematical model for calculating sound velocity in emulsion polymerization has been developed. With respect to previous modeling approaches, its main features are as follows: (1) the application to three‐phase, reacting systems of Urick equation (usually adopted for estimating sound velocity in multiphase, dispersed, unreacting systems, such as emulsions and suspensions); and (2) the development of an empirical relationship for estimating particle compressibility as a function of conversion during the reaction. The model has been validated through several sets of experimental data of batch and semibatch homo‐ and copolymerizations involving styrene, butyl acrylate, vinyl acetate, and methyl methacrylate. In most of the examined cases, the performances of the calibration model are satisfactory. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1451–1477, 1999     

Physical Properties of Triglycerides. I. Density and Refractive Index

Densities and refractive indices of the Na_D, Hα, Hß and the Hγ lines have been measured for a number of triglycerides at 20°C and at 40°C. Based on the additivity principle, relations have been developed between the refractive index, density, iodine value and other physical properties of triglycerides. Quantification of these relations was carried out based on the prime data obtained from the model triglycerides and from data on fatty acid methyl esters.     

零价Mn促进Fe/C微电解反应速率及降解污染物机理

铁碳微电解工艺处理废水效率低,易出现板结问题,仅适用于处理酸性废水。为了扩宽铁碳微电解工艺的适用范围及提高处理效率,研究采用添加零价Mn构建Fe/Mn/C三元微电解体系处理甲基橙(MO)模拟染料废水。利用SEM-EDS、傅里叶红外光谱及拉曼光谱分析铁、锰和活性碳表面形貌的变化及元素组成,采用紫外可见光谱和三维荧光光谱等探究有机物成分的变化,对比Fe/Mn/C和Fe/C微电解体系对甲基橙的降解效果,揭示Fe/Mn/C三元微电解体系降解甲基橙的反应机理和反应动力学。结果表明：反应后的铁、锰、碳填料表面存在铁氧化物、氢氧化物及锰氧化物,Fe/Mn/C三元微电解可断裂甲基橙的氮氮双键,破坏苯环结构。甲基橙的降解过程符合二级反应动力学;Fe/C微电解体系加入零价Mn后,甲基橙降解的反应速率常数由5.7381×10_^-4 min_^?1提高至9.38336×10_^-4 min_^?1,降解速率和降解效果显著优于Fe/C微电解。     

Physicomechanical characteristics of superhard polycrystalling materials

Experimental investigations of the hardness, facture toughness, and elastic characteristics (longitudinal velocity of sound waves, Young's modulus, and Poisson coefficient) of almost poreless polycrystalline ceramic materials based on corundum, higher borides of aluminum and calcium, boron and silicon carbides, boron (cubic) and aluminum nitrides, tungsten-free TiB₂-based solid alloy, cordierite ceramics, ceramics from a mixture of copper titanate and copper aluminate, and metalloceramic materials of the B₄C-SiC-Al-Si system are described. It is established that a linear correlation between the hardness and the velocity of sound waves exists for ceramic and metalloceramic materials. It is shown that ceramic materials can be classified in accordance with their rigidity and capacity for absorbing the energy of ballistic impact, the value of the Poisson coefficient, and a combined criterion comprising hardness, fracture toughness, Young's modulus, and the longitudinal velocity of sound waves. The physicomechanical properties of cermets in the B₄C-SiC-Al-Si system can be controlled by changing the amount of the metallic phase and the annealing time. Translated from Ogneupory, No. 9, pp. 2 – 5, September, 1995.     

Mn促进Fe/C微电解反应速率及降解污染物机理

为了扩宽铁炭微电解工艺的适用范围及提高处理效率,以铸铁屑、椰壳活性炭为原料,添加Mn构建Fe/Mn/C三元微电解体系处理甲基橙(MO)模拟染料废水。利用SEM-EDS、FTIR及Raman光谱分析了Fe、Mn和活性炭表面形貌及元素组成,采用UV和三维荧光光谱(EEM)探究了有机物成分的变化,对比了Fe/Mn/C和Fe/C微电解体系对MO的降解效果,揭示了Fe/Mn/C三元微电解体系降解MO的反应机理和反应动力学。结果表明,反应后的Fe、Mn和炭填料表面存在铁氧化物、铁氢氧化物及锰氧化物,Fe/Mn/C三元微电解体系可断裂MO的氮氮双键,破坏苯环结构。MO的降解过程符合准一级反应动力学模型;Fe/Mn/C微电解体系对MO降解的反应速率常数由Fe/C微电解体系的5.7381×10^–4 min^–1提高至9.3834×10^–4 min^–1,降解速率和降解效果显著优于Fe/C微电解体系。     

Selective Production of Terminally Unsaturated Methyl Esters from Lactones Over Metal Oxide Catalysts

Metal oxide catalysts were studied for their selectivity for the production of a terminally unsaturated methyl ester, methyl 5-hexenoate (M5H), from a 6 carbon, 6-membered ring lactone, δ-hexalactone (DHL). A 15 wt% Cs/SiO₂ catalyst had a selectivity of 55% to M5H. This selectivity was the highest of the metal oxide catalysts studied, which were Cs/SiO₂, MgO, SrO, CeO₂, ZrO₂, Ta₂O₅, MgAl₂O₄, and a Mg–Zr mixed oxide. The Cs/SiO₂ catalyst was utilized for the ring-opening of γ-valerolactone (GVL), a 5 carbon, 5-membered ring lactone. The catalyst was 88% selective to the terminally unsaturated methyl ester, methyl 4-pentenoate (M4P). Weight hourly space velocity studies determined that the unsaturated ester distributions remained constant and no C=C double bond isomerization occurred. Liquid phase transesterification reactions with DHL and methanol and nuclear magnetic resonance spectroscopy confirmed that DHL undergoes ring-opening transesterification to produce an ω-1 hydroxy methyl ester, methyl 5-hydroxyhexanoate (M5HH). Liquid phase transesterification reactions and thermochemistry calculations established that the equilibrium for GVL transesterification with methanol was favored towards the ring-closed lactone instead of the ring-opened hydroxy ester because of the decreased ring strain of GVL compared to DHL. The difference in terminally unsaturated methyl ester selectivity between GVL and DHL manifests from the difference in ring-strain energy. DHL passes through the M5HH intermediate as a result of greater ring strain, while the production of M4P from GVL most likely occurs through a direct, concerted mechanism.

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Possible fatty acyl pheromone precursors in Spodoptera littoralis. Search for 11- and 12-hydroxytetradecanoic acids in the pheromone gland

Lipidic extracts of Spodoptera littoralis pheromone glands submitted to acid methanolysis using: (i) sulfuric acid/methanol/benzene (0.1∶4∶2, by vol) at 90°C for 1 h; (ii) 12 N HCl/methanol (1∶2; vol/vol) at 90°C for 1 h, or (iii) 14% BF₃-MeOH at 90°C for 1 h did not reveal the presence of either 11- or 12-hydroxytetradecanoic acid in the extracts, as concluded from the gas chromatography-mass spectrometry analyses. Under the above methanolysis conditions, a synthetic sample of methyl (14, 14, 15-²H₃) 12-hydroxytetradecanoate remained unaltered. These results may indicate that formation of (E)-11-tetradecenoic acid from tetradecanoic acid does not occur in the pheromone gland by dehydration of an intermediate hydroxyacid. Acid methanolysis of a lipidic extract using BF₃-MeOH led to the formation of a mixture of methoxy fatty acid methyl esters, identified by gas chromatography-mass spectrometry. These methoxy derivatives should arise from BF₃-catalyzed addition of methanol to the double bond of the natural monounsaturated fatty acyl derivatives present in the gland. Thus, under the same conditions, a synthetic sample of methyl (Z)-11-tetradecenoate was partially transformed into methyl 11-methoxytetradecanoate and methyl 12-methoxytetradecanoate. This reaction might be a useful alternative procedure to obtain methoxy derivatives of olefins, which are very helpful for the structural characterization of the parent alkenes.     

癸酸甲酯、月桂酸甲酯和肉豆蔻酸甲酯的液相声速测量

癸酸甲酯、月桂酸甲酯和肉豆蔻酸甲酯3种脂肪酸甲酯是生物柴油的主要成分,其声速是喷油系统优化设计和等熵压缩因子计算中所必需的参数之一。针对癸酸甲酯、月桂酸甲脂和肉豆蔻酸甲脂3种物质声速实验数据缺乏的现状,利用布里渊光散射法,沿0.1、2.5、5.5和8.5 MPa 4条等压线,在288.15~498.15 K温度范围内,分别测量了癸酸甲酯、月桂酸甲酯和肉豆蔻酸甲酯的液相声速;分析了声速随温度、压力的变化规律;依据实验数据,给出了在本文p-T热力学区域内,3种物质液相声速与温度和压力的关联式;关联式计算值与实验数据的相对偏差绝对平均值分别为：0.17%（癸酸甲酯）、0.10%（月桂酸甲酯）和0.15%（肉豆蔻酸甲酯）,满足工程应用需求。     

Laundry Detergency of Solid Non-particulate Soil or Waxy Solids: Part I. Relation to Oily Soil Removal Above the Melting Point

In this work, methyl palmitate or palmitic acid methyl ester, a monoglyceride, was used as both a model solid fat below the melting point and as an oily soil above the melting point. An anionic extended surfactant [branched alcohol propoxylate sulfate sodium salt (C₁₂₃‐(PO)₄‐SO₄Na)] was used to remove methyl palmitate from cotton and from polyester. Above the melting point (~30 °C) of methyl palmitate, the maximum oily soil removal was found to correspond to the lowest dynamic interfacial tension, as is common with liquid soils. Below the melting point, the lower the contact angle of the wash solution against the soil (indicating higher wettability), the higher the solid fat soil detergency. The removed methyl palmitate was found to be mostly in unsolubilized droplets or particles with a small fraction of micellar solubilization for both solid and liquid forms. The presence of surfactant can prevent the agglomeration of detached methyl palmitate particles in both liquid and solid forms, reducing redeposition and enhancing detergency. Below the melting point, the surfactant aids the solution wetting the surfaces, then penetrating the waxy solid, causing detachment as small particles, and dispersion of these particles. Unlike particulate soil detergency, electrostatic forces are not the dominant factor in fatty soil detergency.     

Theoretical and Experimental Studies on Acetylene Absorption in a Polytetrafluoroethylene Hollow‐Fiber Membrane Contactor

The separation of acetylene from a gas mixture was investigated using a polytetrafluoroethylene hollow‐fiber membrane contactor and 1‐methyl‐2‐pyrrolidinone as absorbent. The effects of the gas velocity, the liquid velocity, the feed gas concentration, and the module length on the acetylene mass transfer were investigated. The results showed that the acetylene mass transfer flux increased with increasing liquid velocity, gas velocity, and feed gas concentration, but decreased with increasing membrane module length. A mathematical model was used to predict the wetting extent of the membrane and the mass transfer resistance in the acetylene mass transfer process. The wetting extent of the membrane was found to increase with increasing liquid velocity and to be effectively restrained with increasing gas velocity. The liquid phase resistance and the wetted‐membrane phase resistance controlled the acetylene mass transfer in the acetylene absorption process. The acetylene absorption efficiency was maintained at 90 % for 114 h of the C₂H₂ membrane absorption–thermal desorption cycle process.     

Acoustical Properties of Glasses with the Eutectic Composition Si20Te80 and Different Degrees of Crystallinity

The data on the absorption and velocity of sound in Si₂₀Te₈₀ telluride glasses have been obtained over wide ranges of temperatures (30–300 K) and frequencies (14–700 MHz). The nonlinear elastic properties of these glasses are investigated. A theoretical analysis showed that the sound absorption is governed by the interaction of sound with a system of double-well defects characterized by a broad distribution of energy barriers, whereas the change in the velocity of sound with an increase in temperature is caused by its interaction with thermal phonons. It is found that the system of crystallites 100 Å in size does not affect the sound absorption and velocity but essentially changes the nonlinear elastic properties. The parameters of the system of double-well defects and the averaged Grüneisen constant are determined.     

Poly(methyl methacrylate-co-acrylonitrile)

Stable macroradicals of methyl methacrylate were prepared by the azobisisobutyronitrile-initiated polymerization of methyl methacrylate in hexane whose solubility parameter value (δ) differed from that of the macroradical by more than 1.8 hildebrand units and in 1-propanol at temperatures below its theta temperature (84.5°C). The rates of heterogeneous polymerization in hexane and 1-propanol were much faster than that of the homogeneous polymerization in benzene. Stable macroradicals were not obtained in benzene which was a good solvent nor at temperatures above the glass transition temperature (T_t) of the macroradicals. Thus, stable macroradicals of butyl methacrylate (T_g20°C) and and methyl acrylate (T_g3°C) were not obtained at a polymerization temperature of 50°C. Good yields of block copolymers of methyl methacrylate and acrylonitrile were obtained by the addition of acrylonitrile to the methyl methacrylate macroradical in methanol, ethanol, 1-propanol and hexane at 50°C. The rate of formation of the block copolymer decreased in these poor solvents as the differences between the solubility parameter of the solvent and macroradical increased.The block copolymer samples prepared at temperatures of 50°C and above were dissolved in benzene which is a non-solvent for acrylonitrile homopolymer, but is a good solvent for poly(methyl methacrylate) and the block copolymer. The presence of acrylonitrile and methyl methacrylate in the benzene-soluble macromolecule was demonstrated by pyrolysis gas chromatography, infra-red spectroscopy and differential thermal analysis.     

Fluidization Characteristics of SiO2 Nanoparticles in an Acoustic Fluidized

Under the action of an acoustic field, the fluidization behavior of 5–10 nm SiO₂ nanoparticles, with and without surface modification, was investigated. In a packed bed, the sound wave energy has a significant influence on the compact ratio of the bed. Experimental results indicated that the bed of nanoparticle agglomerates can be fluidized smoothly with the assistance of an acoustic field, and the minimum fluidization velocity is initially reduced dramatically with increasing sound frequency and then rises with increasing sound frequency. Under the same experimental conditions, the minimum fluidization velocity of 5–10 nm SiO₂ nanoparticles is greater than that of 5–10 nm SiO₂ nanoparticles with surface modification. The collapse of the bed demonstrates that SiO₂ nanoparticles, surface modified using organic compound, have longer minimum collapse times than SiO₂ nanoparticles.