Kinetics of wear of epoxide coating modified with glass microspheres and exposed to the impact of alundum particles

The influence of epoxide coating modification with glass microspheres on the erosive wear of the coating is discussed in this paper. Increase in the resistance to erosive wear of a three-layer epoxide coating including the interlayer modified with glass microspheres of a diameter <30 μm and a mass fraction of 10% was obtained. It can be accounted for by the damping of energy which is released during the collision between the impact particle and the organic surface and then dumped by the glass microspheres.     

空心玻璃微珠在反射隔热涂料中的应用

阐述了可用于填充反射隔热涂料的空心玻璃微珠的种类和特性,深入分析了空心玻璃微珠在反射隔热涂料中的作用机理。同时列举了空心玻璃微珠填充涂料的优良性能,并对今后空心玻璃微珠在涂料中的发展做出了展望。     

核废料处理用玻璃微珠一次成形的探索

玻璃微珠是一种新型硅酸盐材料,它具有许多独特的优点,如圆度、均匀度、透明度、硬度和反射特性等.随着科学技术的迅速发展,玻璃微珠的用途日益扩大,品种不断增加.本文介绍核废料处理用玻璃微珠的生产制造方法和设备.     

Formation of porous glass via core/shell-structured poly(methyl methacrylate)/powder glass prepared by ultrasonic irradiation in liquid CO2

The formation of porous glass ceramic via core/shell-structured poly(methyl methacrylate)(PMMA)/powder glass was investigated. Core/shell structures were prepared via ultrasonic irradiation in high-pressure liquid carbon dioxide (CO₂) using PMMA microspheres as the core material and glass powder as the shell material. The mean particles sizes of PMMA template microspheres and glass powder were 9.8 μm and 0.9 μm, respectively. After removal of the PMMA template by calcination in air, porous glass was obtained. The products were characterized by scanning electronic microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). The average pore diameter of porous glass was 4.3 μm. Compared with porous glass prepared by the other method, the porous glass prepared by ultrasonic irradiation of liquid CO₂ was achieved the narrow pore size distribution (CV = 35%) and the higher porosity (89%). The pores are not isolated and connected each other. Furthermore, the effects of experimental conditions, such as coating method, crosslink density of the template PMMA microspheres, ultrasonic intensity and calcination temperature, on the product morphology were investigated. The higher ultrasound intensity achieved the uniform coating of PMMA templates with powder glass. The calcination temperature and crosslinked density of PMMA template microspheres affect the pore structure.     

废丝微珠生产工艺及其在公路交通领域的应用

介绍了玻璃纤维废丝微珠的生产工艺流程和生产要点,作为公路交通用反光材料的优点以及原材料对反光材料性能的影响,废丝微珠在公路交通领域制作交通标志、导向、疏导指示牌的要求和发展前景。废丝微珠为玻璃纤维废丝的综合利用提供了途径。     

Preparation of core–shell glass bead/polysulfone microspheres with two‐step sol–gel process

Core–shell microspheres made from glass beads as the core phase and polysulfone (PSf) as the shell phase can act as an absorbent in the separation process or a supporter for chemical reactions. Based on phase‐inversion principles, a two‐step sol–gel method was developed in this work in which ether was added first and H₂O was added second to a PSf‐containing dimethyformamide (DMF) solution to help PSf solidify on the surface of glass beads. The results from scanning electron microscopy, Fourier transform IR, and X‐ray photoelectron spectroscopy showed that a dense layer of PSf (thin to several microns) was coated on the glass beads and the core–shell microspheres were almost monodispersed. The utilization percentages of the glass beads and PSf were high as 100 and 80%, respectively. The thickness of the PSf membrane was calculated to be about 4.3 μm. To obtain well‐monodispersed microspheres, the practical volume ratio of ether to DMF was recommended to be larger than 4.5. The results suggested that the two‐step sol–gel method is a highly efficient process for preparation of glass bead/PSf core–shell microspheres. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3365–3369, 2006     

空心玻璃微球化学镀镍的前处理工艺研究

研究了对空心玻璃微球化学镀镍的几种前处理方法。通过比较不同方法产生的活化效果及镀后产物形貌,认为先对空心玻璃微球进行偶联处理,可以增加微球表面活性点,加快化学镀反应速度,提高微球表面包覆率。     

Experimental study of the effect of microspheres and milled glass in the adhesive on the mechanical adhesion of single lap joints

This article describes several experiments conducted on single lap joints (SLJ) subjected to tensile mechanical loads. Two epoxy adhesives, with slow and fast curing, were used, with a weight of 0%, 3%, and 10% of glass microspheres and milled glass particles, respectively. The adherends used in the construction of the specimens were fiber-reinforced polymers. The types of failures produced in the SLJ specimens were classified according to ASTM standards. The results of the experimental tests on the SLJ with fast-curing epoxy adhesive showed that the use of milled glass and glass microspheres improved the strength of the joint compared with the neat fast-curing epoxy adhesive. As for the experimental test on the joint with slow-curing epoxy adhesive, the results showed that the use of milled glass and glass microspheres decreased its strength when using different additive concentrations compared with the neat slow-curing epoxy adhesive.     

中空玻璃微球和增塑剂改性ACM的性能研究

采用物理共混的方法制备了中空玻璃微球填充的ACM复合材料,研究了硅烷偶联剂WD-40对中空玻璃微珠形态及复合材料性能的影响,考察了不同含量的中空玻珠微球和增塑剂DOP对复合材料性能的影响。结果表明:经过表面处理的中空玻璃微球与ACM的相容性显著提高,控制合适的中空玻璃微球和DOP添加量可获得力学性能最优的ACM复合材料。     

In vitro dissolution of bioactive glass S53P4 microspheres

Static and dynamic in vitro dissolution studies showed large differences for various size-fractions of non-porous, flame-sprayed commercial microspheres (45–500 µm) of bioactive glass S53P4. The smaller the spheres, the more their composition deviated from the nominal glass. The dissolution studies were carried out in simulated body fluid and tris(hydroxymethyl) aminomethane buffer for seven days. The ion concentrations in solutions were analyzed using inductively coupled plasma optical emission spectrometry, and the pH was measured as a function of time. Also, changes in the sphere size distribution and mass losses were determined. The calcium phosphate and the silica-rich layers at the sphere surfaces were investigated using scanning electron microscopy after several immersion times. The smallest (45–90 µm) spheres appeared almost inert. In contrast, typical silica-rich and calcium phosphate layers were identified at the largest spheres after three days of static and dynamic dissolutions. During the past years, bioactive glass microspheres have been added to paste-like injectable bone grafting materials, putties to enhance their molding properties. The obtained results provide a better understanding of the dissolution patterns of bioactive glass microspheres.     

发泡剂对空心石英玻璃微球结构的影响

空心玻璃微球因具有低密度、高强度、耐高温等优点而被广泛研究。采用喷雾造粒法与粉末法相结合,掺入发泡剂,以射频等离子体作为热源制备空心石英玻璃微球,研究了SiC、CaSO₄、CaCO₃三种发泡剂对制备空心石英玻璃微球的影响。结果表明,通过喷雾造粒法将发泡剂与SiO₂充分混合形成粗坯颗粒,再利用射频等离子设备对粗坯粉末进行高温烧结,得到空心石英玻璃微球。其中CaSO₄、CaCO₃发泡剂效果较差,所产生的气体难以留在玻璃微球内部形成中空气泡;而SiC发泡剂效果最好,在射频等离子烧结过程中产生气体,被玻璃液包裹形成空心结构,得到的玻璃微球平均真密度为1.799 5 g/cm³。选用菲利华石英块状疏松体作为SiO₂原料,当m(SiO₂)∶m(SiC)∶m(H₂O)为100∶3∶300时,可制备出平均真密度为0.72 g/cm³的空心多孔石英玻璃微球。     

Preparation of translucent YAG glass/ceramic at temperatures below 900 °C

The work presented here deals with the preparation of bulk yttrium aluminium garnet (YAG) glass-ceramics and YAG ceramics from glass microspheres with a YAG composition. Sol-gel prepared YAG powder was fed into a high temperature methane-oxygen flame where the particles melted and glass microspheres, with a YAG composition, were formed. Viscous flow sintering of the microspheres was then performed to prepare bulk YAG glass-ceramics or ceramics in a hot press.Rapid crystallization of YAG glass was traced during hot pressing through a change in the heating rate slope due to release of latent (crystallization) heat. This allowed control of crystallization and enabled preparation of YAG-based materials with different amounts of residual glass. YAG ceramic with relative density of 94.2 % was prepared at 891 °C without isothermal heating; additionally, YAG glass-ceramic reached relative density > 99 % at temperature 815 °C without isothermal heating.     

空心玻璃微球高压贮氢技术

利用炉内成球技术制备的亚毫米量级空心玻璃微球进行实验,系统研究了玻璃微球高压贮氢技术.玻璃微球直径150～250 μm,壁厚0.9～4.0 μm.采用气体渗透法充氢,在高温时,气体扩散进入微球内,温度降低后气体不容易扩散出来,即可实现贮氢.通过控制外界温度和气氛可实现氢气的贮存和释放.对于直径200 μm,壁厚1 μm的空心玻璃微球,在350℃充气的平衡时间约6～10 h,充气平衡后,微球内外压基本相等.在室温条件下,微球的保气半寿命约40～50 d.对于直径200 μm,壁厚2 μm的空心玻璃微球,球内氢气最高压力可达20～25 MPa,单位质量贮氢效率为13%～16％.     

Preformed microspherical inclusions for rheological control and physical property modification of epoxy resins

Epoxy microspheres, with average diameters in the order of 4–5 μm, were first produced as insoluble gel resulting from the reactions of a bisphenolic epoxy resin with an aromatic hardener in solution. They were then used as reactive flow modifiers and toughening agents for bisphenolic epoxy resins with same chemical composition. Thermal analysis, rheological measurements, and impact tests were performed to assess their ability to modify the viscosity of the uncured resin and to determine the effects on the cured resins with respect to the glass transition temperature and impact strength. Two similar epoxy systems modified with the addition of different amounts of microspheres preserve the glass transition temperature of the cured unmodified epoxy. The addition of microspheres is responsible for secondary transition. The addition of a small fraction of microspheres does not affect the reactivity of the epoxy resin, while the inclusion of a higher content leads to a noticeable reduction in the gel time of the epoxy systems, indicating that microspheres are not inert fillers. Finally, a limited enhancement of the toughness of the epoxy resin was observed, as a consequence of strong interactions between the matrix and the microspheres. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 748–757, 2006     

表面改性过程对空心玻璃微球性能的影响研究

空心玻璃微球是制备复合泡沫材料的关键原料,对其进行表面改性有利于改善复合材料的性能。但目前的研究甚少关注处理过程对微球性能的影响,不利于复合材料的进一步优化设计。因此,本文拟在制备空心玻璃微球的基础上,通过改变处理液组成、处理时间等条件,测试微球粒子密度、抗压强度等变化情况,研究改性过程对其性能的影响。实验结果表明,改性过程中水会侵蚀玻璃壳体,导致其粒子密度随处理时间的延长、酸度的增大而降低,抗压强度也随之下降。采用适当浓度的Al2(SO4)3水溶液处理微球可以在其表面形成新的膜层,改善抗压强度。     

Ceramic Microspheres for Biomedical Applications

Ceramic microspheres are expected to be useful for cancer treatment and antibacterial treatment. In this article, several attempts to prepare ceramic microspheres for such biomedical applications are described. Ceramic microspheres containing large amounts of yttrium or phosphorus are useful for radiotherapy of cancers, since they can be activated to become β-emitters by neutron bombardment. Ferrimagnetic microspheres are useful as thermoseeds for hyperthermia of cancers because they can heat cancers locally by hysteresis loss of the ferrimagnetic materials under an alternating magnetic field. Silver-containing silica glass microspheres are useful as antibacterial materials when mixed with organic polymers, particularly fine-spun polymer fibers.     

Preparation of phenolic hollow microspheres via in situ polymerization

BACKGROUND: Phenolic hollow microspheres with a closed structure have a set of outstanding thermal characteristics. In the work reported here, a facile method is introduced to fabricate phenolic closed hollow microspheres by in situ polymerization in oil‐in‐water emulsion. Although in situ polymerization has been widely used to prepare hollow microspheres, it has not been utilized for the preparation of phenolic hollow microspheres. RESULTS: The average particle size of the produced microspheres was about 500 µm. Fourier transform infrared spectroscopy indicated that the phenolic microspheres were partially cured during preparation and a significant number of hydroxymethyl groups remained in the microspheres. Thermogravimetric analysis showed that the thermal decomposition temperature of the phenolic hollow microspheres was 420 °C, and residual weight at 800 °C was 62%. Differential thermal analysis showed that the glass transition temperature of the phenolic hollow microspheres was 200 °C. CONCLUSION: Using in situ polymerization, high thermal performance phenolic hollow microspheres are produced. The resultant product possesses a satisfactory closed hollow structure with controlled morphology. Copyright © 2009 Society of Chemical Industry     

Thermophysical properties of composites formed from ethylene–vinyl acetate copolymer and silver‐coated hollow glass microspheres

The primary purpose of this study was to prepare a new type of silver‐coated hollow glass microspheres and to make available this facility for the fabrication of thermally conductive polymeric composites based on ethylene–vinyl acetate (EVA) copolymer. Thermally conducting composites could be produced with a silver coating around the hollow glass microspheres, despite the low silver volume content. The experimental results are discussed and compared to various theoretical models. The thermal diffusivity and the specific heat of the composites were also characterized and are reported. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Detonation Velocity of Emulsion Explosives Containing Cenospheres

The detonation velocity of an emulsion explosive containing hollow alumosilicate microspheres (cenospheres) as the sensitizer is measured. The size of the microspheres is 50–250 μm. The relations between the detonation velocity and the charge density and diameter are compared for emulsion explosives containing cenospheres or glass microballoons as the sensitizer. It is shown that for a 55 mm diameter charge, the maximum detonation velocity of the composition with cenospheres of size 70–100 μm is 5.5–5.6 km/sec, as well as for 3M glass microballoons. The critical diameter for the emulsion explosive with cenosphere is 1.5–2 times larger than that for the emulsion explosive with glass microballoons and is 35–40 mm. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 119–127, September–October, 2005.     

新型隔热保温涂料的研制

介绍了一种引入了膨胀微球的新型隔热保温涂料的研制方法,并将该涂料与普通涂料、玻璃微球保温涂料进行了比较。结果表明,引入了膨胀微球后涂料密度大幅降低,隔热和保温(特别是内保温)性能较普通涂料和玻璃微球涂料相比都有了明显的提高。