Synthesis and properties of hyper-dispersants

The synthesis and properties of three kinds of hyper-dispersants are studied in this paper, which are non-terminated, carboxyl-terminated and polyethylene imine grafted poly（hydroxyl carboxylic acid） ester. The hyper-dispersants are synthesized by the materials of 12-hydroxy-stearic acid, stearic acid and polyethylene imine, which are used to improve the dispersion properties of nano titanium dioxide （nano-TiO2） in low-concentration resin solution system. The influences of hyper-dispersants on the viscosity and stability of the system are studied. It is found that polyethylene imine grafted hyper-dispersant has the best dispersion performance in nano-TiO2 dispersion system, and the optimal content of the hyper-dispersant is 4%.

Simulation on dissolute and dust dispersion in comprehensive mechanized heading face with forced-exhaust ventilation

According to the characteristics of comprehensive mechanized heading face, established the mathematical model of single-phase air flow with κ-ε two equations model, and have established κ-ε-θ-κp mathematic model to solve two-phase flow of gas and particles in dust space with eulerian-eulerian method and eulerian-lagrangian method. Numerical solution of gas-particle two-phase flow was put forward based on collocated grid SIMPLE algorithm. Moreover, numerical simulation of dust concentration in fully mechanized caving face was carded out by using Fluent software. Finally, when in forced-exhaust ventilation circumstance, drawer type fan drum have less dust absorption, and most of dust spread to the other site; the dust concentration is inversely proportional to the distance from tunneling head, and the dust concentration has already diffused to decrease below 102 mg/m3 at the position ofx=12 m. Dust are more focused on relative side（in the range about y from 0 to 2 meter） of roadway space of press-ventilated fan drum, especially between tunneling place and drawer type fan drum; the roadway with road header have a higher dust concentration. These conclusions provide reliable theory basis for the dust prevention in comprehensive mechanized heading face.

Matrix Solid-phase Dispersion Extraction of Alkaloids from the Roots of Aconitum kusnezoffii Reichb

Matrix solid-phase dispersion（MSPD） was developed for the extraction of four alkaloids, including aconitine, mesaconitine, hypaconitine and deoxyaconitine, from the roots ofAconitum kusnezoffii Reichb. The determination of the analyte was carried out by high performance liquid chromatography with UV detection. The alkaline alumina was used as sorbent. The mixture of acetonitrile and water was used as elution solvent. Several extraction parameters, such as type of sorbent, the ratio of sample to solid support material, type of the elution solvent and the volume of the elution solvent were tested. Mean recoveries ranged from 93.16% to 102.73%, with relative standard deviations from 0.27% to 4.17%. With the extraction efficiency and time expenditure taken into account, MSPD extraction should be a comparatively good method.

1-氨基-2-(N,N-二甲氨基)-4-羟基-蒽醌的合成新方法

以分散红60和DMF为原料,在碳酸钾作用下反应制备得到1-氨基-2-(N,N-二甲氨基)-4-羟基-蒽醌,产品收率92.8%。

气相色谱-负化学源质谱联用法测定水产品及食用油中氟乐灵的残留量

建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取，4℃冷藏后，采用分散型固相萃取法净化，由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证，同位素内标法定量。在1～40μg / L 范围内氟乐灵农药的线性关系良好；方法定量限（LOQ）为0.02μg / kg；对鳗鱼、烤鳗、梭子蟹、小龙虾、猪油和橄榄油等6种复杂基质进行1.0、2.0和3.0μg / kg 等3个水平的添加回收试验，平均回收率均处于80％～100％之间，RSD≤10.3％；无干扰现象出现。该方法可作为水产品及食用油中氟乐灵残留检测的确证方法。

RA-g-PHS超分散剂对PP/MCF木塑复合材料性能的影响

采用自制松香海松酸接枝聚十二羟基硬脂酸(RA-g-PHS)超分散剂改性聚丙烯(PP)/剑麻纤维素微晶(MCF)木塑复合材料,研究了RA-g-PHS超分散剂用量对PP/MCF木塑复合材料力学性能、熔体流动速率和热性能的影响,并用扫描电子显微镜(SEM)对PP/MCF木塑复合材料冲击断面形貌的微观结构进行分析。结果表明,当RA-g-PHS超分散剂用量为2%时,PP/MCF木塑复合材料的冲击强度为13.68 kJ/m^2,熔体流动速率为2.06 g/10 min,相比未添加RA-g-PHS超分散剂的PP/MCF木塑复合材料分别提升了100%和34.6%,且热稳定性最好。

磺化苯乙烯-马来酸酐接枝共聚物超分散剂的研究进展

磺化苯乙烯-马来酸酐接枝共聚物由于具有特殊的分子结构,是良好的分散剂。介绍了合成磺化苯乙烯-马来酸酐接枝共聚物的3种方法,并叙述了这些方法的优缺点以及目前的研究进展。同时也对这种分散剂的分散机理进行了简单的介绍。

超支化聚酯-酰胺/聚氨酯水分散体制备及成膜性能研究

将聚氨酯预聚体接枝到以季戊四醇为核,二羟甲基丙酸、二异丙醇胺、六氢苯酐为单体的超支化聚酯-酰胺上,得到了聚氨酯/超支化聚酯-酰胺(PU-HP)杂化水分散体。采用了IR、SEM和化学滴定等方法对产物进行了表征和分析。试验表明超支化聚氨酯水分散体的粒径约50nm,在水中有良好的分散性和稳定性;以S-100水性固化剂可以制得耐水性较好的涂膜,同时具有良好的成膜性和物理性能;并确定了S-100的用量为树脂用量的30%。

Symplectic analysis for elastic wave propagation in two-dimensional cellular structures

On the basis of the finite element analysis, the elastic wave propagation in cellular structures is investigated using the symplectic algorithm. The variation principle is first applied to obtain the dual variables and the wave propagation problem is then transformed into two-dimensional （2D） symplectic eigenvalue problems, where the extended Wittrick-Williams algorithm is used to ensure that no phase propagation eigenvalues are missed during computation. Three typical cellular structures, square, triangle and hexagon, are introduced to illustrate the unique feature of the symplectic algorithm in higher-frequency calculation, which is due to the conserved properties of the structure-preserving symplectic algorithm. On the basis of the dispersion relations and phase constant surface analysis, the band structure is shown to be insensitive to the material type at lower frequencies, however, much more related at higher frequencies. This paper also demonstrates how the boundary conditions adopted in the finite element modeling process and the structures＇ configurations affect the band structures. The hexagonal cells are demonstrated to be more efficient for sound insulation at higher frequencies, while the triangular cells are preferred at lower frequencies. No complete band gaps are observed for the square cells with fixed-end boundary conditions. The analysis of phase constant surfaces guides the design of 2D cellular structures where waves at certain frequencies do not propagate in specified directions. The findings from the present study will provide invaluable guidelines for the future application of cellular structures in sound insulation.

A novel type of transverse surface wave propagating in a layered structure consisting of a piezoelectric layer attached to an elastic half-space

The existence and propagation of transverse surface waves in piezoelectric coupled solids is investigated, in which perfect bonding between a metal/dielectric substrate and a piezoelectric layer of finite-thickness is assumed. Dis- persion equations relating phase velocity to material con- stants for the existence of various modes are obtained in a simple mathematical form for a piezoelectric material of class 6mm. It is discovered and proved by numerical examples in this paper that a novel Bleustein-Gulyaev （B-G） type of transverse surface wave can exist in such piezoelectric cou- pled solid media when the bulk-shear-wave velocity in the substrate is less than that in the piezoelectric layer but greater than the corresponding B-G wave velocity in the same pie- zoelectric material with an electroded surface. Such a wave does not exist in such layered structures in the absence of pie- zoelectricity. The mode shapes for displacement and electric potential in the piezoelectric layer are obtained and discussed theoretically. The study extends the regime of transverse sur- face waves and may lead to potential applications to surface acoustic wave devices.

Compact Model for the Obnoxious <i>p</i>-Median Problem

Obnoxious facilities are those crucial to human living, yet antagonistic to the public or environment. However, the interactions between obnoxious facilities and their clients have been less frequently investigated. A state-of-the-art model for this problem involves numerous 0 - 1 variables, rendering it difficult to solve. This study aims at removing most of these 0 - 1 variables to enhanced model efficiency. A compact model is presented in this study, with the equivalence between the new and original models proved. Additionally, numerical tests were conducted to show that the proposed compact model is more efficient than the original one.

Stable CuO/La_(2)Sn_(2)O_(7) catalysts for soot combustion:Study on the monolayer dispersion behavior of CuO over a La_(2)Sn_(2)O_(7) pyrochlore support

To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO loadings were fabricated and characterized by different techniques and density functional theory calculations.In these catalysts,a spontaneous dispersion of CuO on the La_(2)Sn_(2)O_(7)pyrochlore support formed,having a monolayer dispersion capacity of 1.90 mmol CuO/100 m^(2) La_(2)Sn_(2)O_(7)surface.When loaded below this capacity,CuO exists in a sub-monolayer or monolayer state.X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,and Bader charge and density of states analyses indicate that there are strong interactions between the sub-monolayer/monolayer CuO and the La_(2)Sn_(2)O_(7)support,mainly through the donation of electrons from Cu to Sn at the B-sites of the structure.In contrast,Cu has negligible interactions with La at the A-sites.This suggests that,in composite oxide supports containing multiple metals,the supported metal oxide interacts preferentially with one kind of metal cation in the support.The Raman,in situ diffuse reflectance infrared Fourier transform spectroscopy,and XPS results confirmed the formation of both O2^(-)and O2^(2-)as the active sites on the surfaces of the CuO/La_(2)Sn_(2)O_(7)catalysts,and the concentration of these active species determines the soot combustion activity.The number of active oxygen anions increased with increase in CuO loading until the monolayer dispersion capacity was reached.Above the monolayer dispersion capacity,microsized CuO crystallites formed,and these had a negative effect on the generation of active surface oxygen sites.In summary,a highly active catalyst can be prepared by covering the surface of the La_(2)Sn_(2)O_(7)support with a CuO monolayer.

超细粉体的水性超分散剂研究进展

超细粉体具有极高的比表面能而难于在水介质中稳定分散。具有锚固基团和溶剂化链结构组成的超分散剂能显著降低体系的总表面能,因而可用于分散超细粉体。文章概述了超细粉体在水介质中的分散机理、双电层理论和空间位阻理论,以及颗粒分散动力学稳定性的影响因素如分子组成结构、pH和分散剂用量。重点介绍了水性超分散剂的种类包括聚羧酸型、聚马来酸酐型和聚磺酸型等及其合成方法。

PP/纳米CaCO_3分散体系的研究

本文研究了不同的分散剂对PP/纳米CaCO3 体系的分散效果 ,以及加工工艺条件对该体系的影响。结果表明 :超分散剂CH -1A对纳米CaCO3 有显著的分散作用 ,使体系的冲击强度有了大幅度提高。在使PP完全塑化的前提下 ,超分散剂CH -1A使纳米CaCO3 在PP中随转速的提高其分散效果也提高 。

超分散剂对纳米TiO_2的表面改性研究

采用超分散剂对纳米TiO2粉体进行表面改性,可将超分散剂分子成功地包覆于TiO2表面,对TiO2表面进行非极性修饰,使其表面由极性亲水性变为非极性亲油性。由沉降性实验观测到超分散剂改性后的纳米TiO2粒子可在非极性溶液中稳定悬浮960h以上;透射电镜(TEM)观测到改性后的TiO2粒子在非极性溶剂中呈纳米级分散状态,团聚体的粒径基本控制在100nm以内;通过润湿性测试及红外分析观察到,颗粒表面由亲水性变为疏水性,纳米TiO2颗粒表面增加了-CH2-和C=O-O基团键的振动峰,因而可以判断纳米TiO2表面状态发生了改变,使TiO2与非极性材料具有较好亲和相容性。本实验也证明了TiO2表面亲油改性的可行性。

超分散剂改性滑石粉填充PP复合材料的性能研究

研究了YB超分散剂改性滑石粉填充聚丙烯(PP)复合材料的流变行为及力学性能。结果表明,复合材料的熔体质量流动速率(MFR)明显提高,且随着超分散剂用量的增加,MFR增大;复合材料的表观黏度随着剪切速率增大而降低;随着滑石粉用量的增加,体系表观黏度对温度的敏感性越来越小。滑石粉用量及超分散剂用量的增加对复合材料的拉伸强度、弯曲强度以及弯曲模量都有一定的改善和提高,而对其冲击强度的影响则是先增大后降低。

聚丙烯酸钠超分散剂的合成及其分散性能研究

通过调节共聚单体丙烯酸(AA)、甲基丙烯酸(MAA)、马来酸酐(MAn)的摩尔比与引发剂种类及其用量,合成了一系列低分子质量的聚丙烯酸钠超分散剂。当n(AA)∶n(MAA)∶n(MAn)=1.5∶1.5∶1、还原剂(NaHSO3)与氧化剂((NH4)2S2O8)的摩尔比为1.5∶1、氧化剂((NH4)2S2O8)用量为共聚单体质量的17.4%时,合成的超分散剂GCC-44对重质碳酸钙悬浮液有较好的降黏作用和分散稳定性。采用红外光谱仪和粒度分析仪对该超分散剂与碳酸钙颗粒表面的相互作用进行了研究,结果表明,超分散剂GCC-44与碳酸钙颗粒表面存在化学结合,GCC-44的合适掺量为碳酸钙质量的0.2%。

SML超分散剂的合成及在复合材料中的应用

介绍了超分散剂对粉体改性机理,并合成了SML超分散剂,考察了其改性超细CaSO4粉体后的活化指数,同时探讨了SML超分散剂对PE/超细能的影响,最后通过SEM观察了复合材料断面形貌。结果表明,SML超分散剂优于F-2分散剂。在其用量为3%时,活化指数可达97%,复合材料的拉伸强度、冲击强度、弯曲强度分别提高了28.7%、20.7%、4.9%。

超分散剂的合成及其在微细CaSO_4粉体改性中的应用表征

以硅烷为锚固基团(A段),丙烯酸丁酯为溶剂化链(B段),合成了超分散剂YB系列,研究了它对微细CaSO4粉体在液体石蜡中的沉降体积和粘度的影响。结果表明:YB系列超分散剂对CaSO4粉体有很好的分散和降粘作用,当锚固基团与溶剂化链摩尔比为1:10时,超分散剂用量为粉体质量的1%的情况下分散和降粘效果最佳,YB-2超分散剂的改性效果要优于F-2钛酸酯偶联剂和硬脂酸。同时通过对改性前后粉体做了扫描电镜(SEM)和红外光谱(FT-IR)检测,对比显示改性后的CaSO4粉体表面连接了有机基团。

端磷酸酯基聚酯型超分散剂对不饱和聚酯/氢氧化铝复合材料的影响

考察了高分子量和低分子量磷酸单酯、中间酯、双酯6种端磷酸酯基聚酯型超分散剂对UPR/ATH复合材料的影响。研究表明:高分子量磷酸酯超分散剂可以提高氢氧化铝(ATH)在不饱和聚酯(UPR)中的极限填充量,该类超分散剂使ATH在UPR中获得较好分散效果,但磷酸酯基聚酯型超分散剂会对复合材料固化时间有所延长。双酯型超分散剂对冲击强度的提高较显著而单酯型超分散剂对硬度的提高较显著。