苯乙烯—低顺式聚丁二烯预聚体的流变特性

以苯乙烯-低顺式聚丁二烯橡胶接技共聚制备高抗冲聚苯乙烯。研究了胶样、橡胶含量,搅拌转速、温度对预聚体的流变行为的影响。发现随着起始橡胶浓度增加,相转变点推迟,当起始浓度达10％时,体系不发生相转变。     

新拌水泥基材料的流变特性、模型和测试研究进展EI北大核心CSCD

新拌的水泥基材料是典型的屈服应力流体,由不同粒径的固体颗粒形成的悬浮液组成,其固体颗粒的范围从亚微米级到厘米级。当受到剪切作用时流体内部存在两种相反的作用,分别会导致流体发生剪切稀化和剪切增稠,流体的流变特性由二者共同决定。本文对新拌水泥基材料的流变机理、模型以及流变仪测量方面的研究进展进行了综述,对具有代表性的流变模型,包括Bingham模型、Modified Bingham模型和Herschel-Bulkley模型等的特点、适用条件等进行了分类总结。影响流变特性的主要因素是固体颗粒体积分数和剪切速率,当剪切速率与剪切应力之间存在非线性关系时,难以根据流变仪的测量数据建立流变方程。本文中讨论了一些建立模型的新方法,通过计算流体力学和离散元理论相结合可以较好地模拟水泥基材料流变特性。     

钛酸镍水基浓悬浮体的制备及流变特性研究

测定了超细NiTiO3粉体的ζ-电位,并研究了分散剂聚甲基丙烯酸铵(NH4PAA)的用量对NiTiO3悬浮体粘度的影响。结果表明:超细NiTiO3粉体在水中的等电点约为5.0;悬浮体的粘度与分散剂的用量有关,并得出最佳用量约为粉体质量的0.4wt%;研究了不同水基浓悬浮体的流变特性,成功地制备出体积分数为60vol%的低粘度(0.75Pa·S,剪切速率为50S-1)悬浮体。     

各向同性与各向异性天然橡胶磁流变弹性体的导热性能及磁流变性能（英文）

采用羰基铁粉粒子填充天然橡胶磁流变弹性体(MRE),研究了各向同性与各向异性MRE的磁流变性能及导热性能。结果表明,各向异性MRE的热扩散系数和导热系数比各向同性MRE分别提高了30. 1%和41. 9%。同时,随着应变的增大,MRE的相对磁流变效应呈下降趋势,而在相同应变下,各向异性MRE的储能模量以及相对磁流变效应均高于各向同性MRE。     

圆盘式磁流变液传动装置传递力矩分析与测试

针对所设计的一种圆盘式磁流变液传动装置进行了磁流变液传动的转矩分析与实验测试研究。以B ingham模型为基础,推导出转矩、转速及磁感应强度之间的数学关系式;应用有限元数值分析,研究了圆盘式磁流变液传动装置在不同电流强度下磁感应强度沿半径方向的分布规律,进一步利用数据拟合的方法确定了磁感应强度、电流和半径之间的关系,将拟合的表达式代入转矩的计算表达式,最终得到传递转矩和电流强度之间的函数关系式,并进行了相关的实验测试。对实测转矩数据与理论分析得到的转矩数据进行了对比分析及相对误差分析。     

汽车用磁流变液离合器中的磁流变液性能分析

介绍了磁流变液这种智能材料的组成、特性及流变机理,并通过实验对汽车磁流变液离合器系统中磁流变液磁扭转力与电流及其自身磁粉固含量之间的曲线关系进行了分析.     

磁流变弹性体的性能研究

以天然橡胶为基体制备磁流变弹性体（MRE）,研究MRE的Payne效应及磁感应强度和磁流变效应。电子显微镜分析得出,对于羰基铁粉质量分数最大（81.67%）的MRE,羰基铁粉分布密集,出现羰基铁粉团聚现象。流变仪测试结果表明：随着羰基铁粉质量分数的增大,MRE的Payne效应和磁流变效应增强;随着应变的增大,MRE的储能模量减小,损耗因子增大。     

聚合物特性黏度称重增浓外推测试新方法

根据黏度测量基本原理建立了聚合物稀溶液特性黏度测试新方法——称重增浓外推法。使用这种方法测定了一系列刚性链大(键共轭结构聚合物的特性黏度,其比浓黏度ηsp/c以及比浓对数黏度In(ηr/c)分别与浓度的关系曲线均呈现良好的线性关系。和传统的稀释外推法以及单点法如Maron法、Solomon-Ciuta法和算图法相比,称重增浓外推法具有数据可靠、准确、低有机溶剂消耗和操作连续省时等优点。     

聚乙烯管材专用料DQ081F质量特性的测试

对该聚乙烯专用料在PE100定级过程中进行的长期性能、常规性能和安全性能评价测试情况进行了研究,为企业提供了规范化的控制依据。     

Surface coated iron particles via atom transfer radical polymerization for thermal–oxidatively stable high viscosity magnetorheological fluid

A surface grafting technique for poly(2‐fluorostyrene) onto iron particles via atom transfer radical polymerization (ATRP) is described. Grafted poly(2‐fluorostyrene)–iron particles were synthesized by immobilizing 2‐4(‐chlorosulfonylphenyl)‐ethyltrichlorosilane to the iron particles through the covalent bond of a silanol group, followed by the polymerization of 2‐fluorostyrene monomer. The grafted polymer–iron particles display a higher thermal transition temperature compared to bulk polymer because the covalent bond between the polymer backbone and the surface of the iron particles restricts the molecular mobility. The molecular weight of the synthesized poly(2‐fluorostyrene) has been measured and it has a narrow molecular weight distribution (M_w/M_n < 1.1). From thermogravimetric analysis, the thermal stability of poly(2‐fluorostyrene) is superior to polystyrene. Also, the high viscosity magnetorheological fluid (HVMRF) prepared from surface coated iron particles has excellent thermo–oxidative stability, having nearly constant viscosity. These materials exhibit a large increase in shear yield stress for the off‐ and on‐state as compared to a benchmark high viscosity magnetorheological fluid (HVMRF) and ‐coated iron particle HVMRF. In addition, this type of fluid eliminates iron particle settling which is a common problem found in traditional magnetorheological fluids (MRFs). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Poly(methyl methacrylate)‐coated carbonyl iron particles and their magnetorheological characteristics

Magnetorheological fluids (MRFs) are types of suspensions that contain magnetic particles and a carrier fluid, and are considered as semi‐active smart materials. By tuning the strength of an external magnetic field, like other traditional MRFs, a carbonyl iron (CI)–poly(methyl methacrylate) (PMMA) particle‐based MRF can change reversibly from a fluid‐like state to a solid‐like state within milliseconds. In the research reported, CI particles were encapsulated with PMMA via emulsion polymerization. After the polymerization, the fabricated CI–PMMA composite particles were dispersed in a suspension medium to prepare MRF. The synthesized CI–PMMA composite particle‐based MRF showed a shear stress of 60 kPa at the magnetic field strength of 0.6 T, and a greatly enhanced anti‐sedimentation stability. Copyright © 2010 Society of Chemical Industry     

Dynamic properties of magnetorheological elastomers based on iron sand and natural rubber

In this study, magnetorheological elastomers (MREs) based on iron sand and natural rubber were prepared. The Taguchi method was employed to investigate the effect of a number of factors, namely, the iron sand content, iron sand particle size, and applied magnetic field during curing on the loss tangent (tan δ) and energy dissipated during cyclic loading. Tan δ was measured through dynamic mechanical analysis over a range of frequency (0.01–130 Hz), strain amplitude (0.1–4.5%), and temperature (?100 to 50°C). The energy dissipated was measured with a universal tester under cyclic tensile loading. The data were then statistically analyzed to predict the optimal combination of factors, and finally, experiments were conducted for verification. It was found that the iron sand content had the greatest influence on tan δ when measured over a range of frequency, and the energy dissipated during hysteresis tests. However, none of the factors showed a significant influence on tan δ when measured over a range of strain amplitude. Furthermore, the iron sand content and magnetic field were also found to influence the width of the peak in tan δ as a function of the temperature. The morphological characteristics of the MREs were also examined with scanning electron microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41506.     

低压(真空)流体状态下的管径计算

在磷酸、磷肥装置的闪蒸过程中,管道中的气体均属于低压流体。在低压状态(或真空状态)下,物料分子间间距加大,分子间碰撞明显减少。其管道直径的计算仅凭工程经验进行简单估算,其结果往往不令人满意。本文就这个问题进行了分析,以找出在低压状态(或真空状态)下计算管径的方法。     

Preparation and properties of magnetorheological elastomers based on silicon rubber/polystyrene blend matrix

Magnetorheological (MR) elastomers, which are mainly composed of magnetic particles and elastic polymer, are a new kind of smart materials whose modulus can be controlled by changing the strength of magnetic fields. In this article, MR elastomers based on immiscible silicon rubber/polystyrene (SR/PS) blend matrix were fabricated successfully via cosolvent method and the MR effect, electric and mechanical properties, and the microstructures of the corresponding materials were studied. SEM studies showed that the dispersion of iron particles in blend matrix were different from that in single polymer, which could be further proved by the different electric conductivity. The MR effect of MR elastomers based on blend matrix varied with the different ratios of SR and PS, which was discussed in detail from the special dispersion of iron particles and of zero‐modulus of MR elastomers. In addition, the MR elastomers based on SR/PS blend matrix had enhanced mechanical properties, which made them more hopeful to be applied in practice. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3143–3149, 2007     

超(近)临界流体技术在环境科学中的应用

对超(近)临界流体技术在环境科学中的应用进行了综述。内容涉及超临界CO2萃取技术在处理工业废弃物及溶剂替代方面的应用,超临界水在处理难降解有机物及生物质废弃物资源化领域的应用及超临界流体技术在环境分析中的应用。     

Synthesis and rheological characterization of nano-magnetorheological fluid using inverse spinel ferrite (NiFe2O4)

In recent years, the utilization of nanoparticles for nano-magnetorheological fluid (NMRF) synthesis is gaining popularity in automotive applications. From this perspective, the nickel ferrite (NiFe₂O₄) nanoparticles were prepared by gel burning method and characterized using the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy-energy dispersive X-ray analysis (FESEM-EDX), and vibration sample magnetometer (VSM). The XRD and FTIR results showed the phase formation and characteristic metal–oxygen M–O vibrations. The FESEM images showed quasi-spherical crystallites with considerable agglomeration. The magnetic properties measured showed the ferromagnetic nature of NiFe₂O₄. The nanosized NiFe₂O₄ was used for NMRF preparation and characterization.     

流化催化裂化(FCC)催化剂跑损机制及故障树分析

炼油厂中流化催化裂化（FCC）装置催化剂跑损的故障原因分析多数来自现场工程师,在故障机理方面少有报道。为了解决这一问题,本文利用故障树分析方法（FTA）,研究FCC装置催化剂跑损机制。采用催化剂跑损为顶事件,结合跑损途径和跑损机理,确定FCC装置故障、操作工艺异常和催化剂颗粒物性3个因素作为中间事件,并通过逐层向下深入分析,确定诸如翼阀磨损等21个因素作为底事件,建立催化剂跑损故障树模型。根据FCC装置故障树风险分析,得到任何一个底事件出现都有可能导致顶事件发生,且对FCC装置催化剂跑损的贡献度相同。研究结果表明：利用FTA方法可以更深层次了解装置跑剂原因,对考察FCC装置催化剂跑损机理具有指导意义,并提出了相应的故障判定流程和跑剂预防措施。     

Characterization and exposure of polyetheretherketone (PEEK) to fluid environments

The sorption and desorption behaviour in fluids is described for polyetheretherketone (PEEK) films of different crystallinity. Water, Skydrol, and methylene chloride were used as fluid environments at two temperatures, and the weight gain of the films as a function of time was recorded. Density, thermomechanical, and dynamic mechanical measurements were made for the films before and after the fluid exposure. The results confirmed the general solvent resistance of PEEK. However, exposure to methylene chloride produced two significant effects: plasticization and additional crystallization for incompletely crystallized films. Exposure to different fluids was shown to suppress the exhibited thermomechanical transitions of these films. For the incompletely and fully crystallized films a comparison was made for crystallinity values obtained by the differential scanning calorimetric and density gradient techniques. Finally,dynamic mechanical and sorption in methylene chloride data obtained for PEEK reinforced with continuous carbon fibres are provided for comparison to the neat polymer results.     

Synthesis and magnetorheological characteristics of ribbon‐like,polypyrrole‐coated carbonyl iron suspensions under oscillatory shear

One of the crucial problems of classical magnetorheological (MR) fluids is their high rate of sedimentation. This disadvantage may be substantially eliminated using core‐shell particles. The aim of this study is to prepare spherical carbonyl iron (CI) particles coated with conducing polymer polypyrrole (PPy) with ribbon‐like morphology. Scanning electron microscopy proved the formation of the ribbon‐like layer onto CI particles while Fourier transform infrared spectroscopy confirmed the chemical structure of PPy. The magnetic properties observed via vibrating sample magnetometer showed decreased magnetization saturation of core‐shell‐structured particles due to the existence of non‐magnetic surface layer. MR measurements performed under oscillatory shear flow as a function of the applied magnetic flux density, temperature, and particle concentration showed that core‐shell particle‐based MR suspension exhibits sufficient MR performance for practical applications. Moreover, the suspension stability is promoted significantly when core‐shell particles are used as a dispersed phase. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013