Vapor‐based polymer coatings for potential biomedical applications

Over the last decade, biology and biotechnology have witnessed an extraordinary development spanning genomics, proteomics, and metabolics. This progress was so rapid and definite that it not only changed the face of modern biology, but indeed altered the way day‐to‐day business is done in biology and related fields. This scientific advancement came with a need for concurrent technological advances. In this context, the ability to interface sophisticated devices with relevant biological microenvironments has emerged as a critical challenge. Already, novel biomaterials are on the horizon that promise to fulfill the rigid criteria of being both biocompatible under the conditions of a versatile range of biological applications and compatible with the increasing demands for miniaturization, integration, and throughput of future device architectures. As currently employed solvent‐based polymer coatings are increasingly reaching their limits, a range of unconventional materials, such as vapor‐based polymer coatings, are discussed as attractive alternatives. One of the main features of vapor‐based polyreactions is their versatility in synthesizing both simple and complex polymers with relative ease and at generally low temperatures. The advantages of the chemical vapor deposition (CVD) technique also include control of the composition and architecture of the resulting materials, high accuracy, solvent‐free environments, excellent adhesion, and the ability to accommodate custom‐tailored surface modifications. For further illustration, selected examples of polymer‐based surface engineering approaches using vapor‐based polyreactions are discussed in this review. For instance, reactive coating technology uses CVD polymerization to deposit a wide range of chemically functionalized polymer coatings on various substrate materials. Its simplicity in providing chemically reactive groups and its applicability to three‐dimensional geometries (e.g. for microfluidics) enables exact tailoring of surface properties and the preparation of biologically relevant microenvironments. CVD‐based reactive coatings are compatible with soft lithographic processes allowing for patterning of proteins, DNA, cytokines, and mammalian cells. Copyright © 2006 Society of Chemical Industry     

二氯乙烷裂解炉燃料气系统的改造

对中国石油化工股份有限公司齐鲁分公司氯碱厂1^#氯乙烯装置进行了改造,将裂解炉燃烧气由C4改为炼油厂焦化干气。介绍了改造方案及改造后装置的运行情况,指出此项改造经济效益显著,可达4315万元／a。     

乙烯裂解炉结焦抑制剂的研究进展

在乙烯装置中,裂解炉结焦是制约装置运行的重要因素。在裂解原料或稀释蒸汽中添加结焦抑制剂是目前延长装置运转周期较为有效的方法之一。综述了国内外乙烯裂解炉结焦抑制剂的技术进展和发展方向,结合我国乙烯裂解装置的情况,提出应加强结焦抑制剂的研究开发,降低抑制剂的成本,优化工业化加剂方案,提高抑制剂的应用技术水平等建议。     

Refractory lining of a furnace for pyrolysis of dichlorethane

Conclusions Compositions of thermal-insulation concrete mixtures from which various elements of the lining of a furnace for pyrolysis of dichlorethane were produced have been developed. Burner blocks for the gas burners of the furnace were produced by vibrocasting.The refractories developed have provided reliable operation of the furnace, and for three years they have been in good condition.Translated from Ogneupory, No. 7/8, pp. 27–29, July–August, 1992.     

New method for the preparation of thick conducting polymer composites

A highly porous and absorbable crosslinked polystyrene, prepared by the concentrated emulsion polymerization method, was used as host polymer for the preparation of conducting, large objects, polymer composites. The composites, whose conductivity can be as high as 0.80 S/cm, were prepared by (i) imbibing the host polymer with a pyrrole (or oxidant) solution, (ii) partially drying the imbibed host polymer, and (iii) imbibing again with an oxidant (or pyrrole) solution for polymerization to take place. The electrical conductivity of the composite and the penetration of polypyrrole in the host polymer are influenced by the polymerization conditions (i.e., the concentrations of oxidant and pyrrole and the nature of the solvents used for the oxidant and pyrrole), the order in which the two imbibing solutions are introduced, and the drying time used after the first imbibation. The mechanical properties of the host polymer are improved with the incorporation of polypyrrole. Scanning electron micrographs of the composites indicate that the polypyrrole coats uniformly as a film the inside of the porous host polymer.     

Large-scale synthesis of hafnium carbide nanowires via a Ni-assisted polymer infiltration and pyrolysis

Hafnium carbide (HfC) nanowires were successfully synthesized on C/C composites via a Ni-assisted polymer infiltration and pyrolysis. Before synthesizing HfC nanowires, the composition and microstructure of the organic HfC precursor and its pyrolyzed products were characterized by Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and X-ray diffraction. The effect of heat-treatment temperature on the morphology and microstructure of HfC nanowires were investigated by scanning electron microscopy and transmission electron microscopy. Results show that HfC nanowires exhibits three-layer core-shell structure, including HfC core, HfO₂ inner shell (~2 nm) and carbon nanosheet outer shell (~1 nm). The obtained HfC nanowire is typically grown along <01> with the diameters of ~100 nm and the length of several micrometers. The growth of HfC nanowire follows the combination of top-type vapor-liquid-solid and solid-liquid-solid mechanism.     

Awl-like HfC nanowires grown on carbon cloth via Fe-catalyzed in a polymer pyrolysis route

Awl-like hafnium carbide (HfC) nanowires were successfully synthesized on carbon cloth in a polymer pyrolysis route via Fe-catalyzed for the first time. A detailed study of the HfC nanowire morphology was performed. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to investigate the morphology and microstructure of the obtained awl-like HfC nanowires and the growth mechanism was also discussed in detail. Results show that HfC nanowires wrapped by amorphous HfO₂ layer with ~10 nm in thickness display awl-like structure and the nanowire's surface exhibit prismatic geometry. The diameter of the nanowire decreases from the bottom (~500 nm) to the top (~100 nm). The growth mechanism of the awl-like HfC nanowires was mainly affected by the combination of bottom-type vapor-liquid-solid (VLS) and solid-liquid-solid.     

聚合物纳米复合材料的制备方法

从纳米微粒的分散方法以及纳米复合材料的成型技术两方面综述了国内外纳米复合材料的制备方法的发展状况,总结了纳米微粒填充法与紫外光辐射固化技术的结合在制备纳米复合材料方面的几种优点,认为该方法是未来聚合物无机纳米复合材料的主要、新型制备方法。     

乙烯裂解炉基础地脚螺栓整体加固控制精度法

介绍了采用螺栓模板整体加固乙烯裂解炉基础地脚螺栓的施工新方法 ,有效地提高螺栓安装质量     

两段式回转炉热解菜籽饼

通过研究菜籽饼的工业分析,发现挥发分比例较高适合对其热解利用,采用热重分析方法分析了厨菜籽饼的热解特性,提出了菜籽饼两段式热解转化利用的思路。在回转炉中对菜籽饼进行热解反应并分析了500 ℃下固液产物的组成和性质,发现固液产率较高,焦油及焦炭品质较好,具有广阔发展前景,为菜籽饼大规模地资源化利用提供了一条新的道路。     

Kinetics of lignite pyrolysis in an entrained-flow,isothermal furnace

An entrained-flow, isothermal furnace was used to study rapid pyrolysis in nitrogen of a Texas lignite. Weight losses for fixed residence times up to 0.4 s were independent of particle size over the range of mean diameter from 41 to 201 μm and increased with temperature elevation over the range 700 to 1000 °C. The maximum yield of volatiles, 66.7 wt% of the dry-ash-free coal, was particle size independent and relatively temperature independent over the range of operating conditions. The maximum yield represented a fractional increase of 1.30 over the ASTM volatile matter. This yield enhancement was associated with a reduction in the preponderence of secondary char-forming reactions of the volatiles and not directly with the increase in heating rate from 20 °C s^?1 in the ASTM test to >10⁴ °C s^?1 in the isothermal furnace. Pyrolysis was multi-stage; initial rapid devolatilization to 50% weight loss was followed by slower latter-stage devolatilization. First stage pyrolysis could be fitted by a single, first-order kinetic expression whether total weight loss was taken as just that for the first stage or for complete devolatilization. Rate constants for the two cases were 0.6 × 10³exp(? 45 kJ/mol/RT) and 0.9 × 10²exp(? 32 kJ/mol/RT) s^?1, respectively. One or more additional equations would be necessary to describe the completion of pyrolysis. It is argued that the relatively low activation energy is not necessarily indicative of physical rate control and therefore not necessarily in contradiction with the absence of particle size effects.     

Metrology for characterizing scratch resistance of polymer coatings

Current methods for scratch resistance assessment are often based on “relative but not quantitative” types of measurements, such as visual inspection, gloss changes, and changes in gray scale level or lightness. Most results are used for qualitative assessment purposes, which result in the lack of a repeatable and reliable standardized test method for the polymer materials community. To implement a scientifically based standardized test method for quantifying scratch resistance, it is vital to understand the relationships between material mechanical properties, morphology, and appearance (optical properties) of surface and subsurface deformation. In this article, preliminary results from a scratch testing protocol to identify the “onset” of plastic deformation in poly(methyl methacrylate) and poly(propylene) commercial samples are presented. Recent advances in optical scattering measurements to identify the onset of plastic deformation by analyzing specular and off-specular intensities are also presented. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

煤制乙炔裂解气的降温工艺

介绍了煤制乙炔工艺中裂解气降温工艺流程并对关键设备的选型进行了详细计算。     

Development of UHTCMCs via water based ZrB2 powder slurry infiltration and polymer infiltration and pyrolysis

C_f/ZrB₂-SiC ultra-high temperature composites were manufactured via aqueous slurry impregnation coupled with polymer infiltration and pyrolysis, using a allylhydrido polycarbosilane precursor. For the first time we used ultra-high modulus pitch-based carbon fibres for the PIP process, investigating three different architectures, 0/0°, 0/90°, and 2D. Microstructure, mechanical properties and oxidation resistance in air at 1650 °C were investigated. As expected, the mechanical properties showed the tendency to decrease with increase of the preforms complexity, due to the higher amount of flaws and residual stresses. For instance, the flexural strength was approaching 500 MPa for 0/0°, 370 MPa for 0/90° and 190 MPa for 2D. The materials showed an optimal resistance to oxidation at 1650 °C thanks to formation of a viscous borosilicate glass that guaranteed a self-healing functionality.     

Facile preparation of superhydrophobic and high oleophobic polymer composite coatings with self-cleaning,heat-resistance and wear-resistance

Superhydrophobic and high oleophobic PPS-matrix composite coatings with excellent self-cleaning, bending/heat/wear-resistance have been successfully prepared by a simple spray method through designing hierarchical structures and modifying with low surface energy groups in this work. The test results showed that the polyphenylene sulfide (PPS)/ 43 wt.% fluorinated ethylene propylene (FEP)/ polyetheretherketone (PEEK)/ 1 wt.% polydimethylsiloxane (PDMS) composite coatings exhibited superhydrophobic and high oleophobic simultaneously, with the highest contact angles of water, glycerine, ethylene glycol, crude oil and oil-water mixture up to 173 ± 1.5°, 156 ± 1.3°, 153 ± 1.3°, 151 ± 1.3° and 155 ± 1.3°, respectively. The wear life of the coating was recorded to be the longest reaching about 30 h without any surface damage until the wear test is terminated, which was 10 times of the PPS/PEEK coating. The intrinsic brittleness of PPS/PEEK coating can be avoided by the addition of FEP. Moreover, the coating can also keep superhydrophobic after immersing in strong acid and base solutions for 15 days. Under the condition of 200 °C for 1 h, the weight losses of the coatings were less than 3 % of the coating, showing outstanding heat-resistance. Under the condition of dirty, the coating also demonstrated the excellent self-cleaning effect, protecting substrates from pollution in practical applications. It is believed that our research provides a new approach to extending the life span of superhydrophobic coatings for petroleum pipeline.     

建筑涂料用乳液的开发动向

本文论述了建筑涂料用乳液如常温交联型乳液、耐污染性乳液、高透湿防水性乳液，施工性和装饰性优异的乳液以及新型复合性乳液的开发动向。     

回转炉在催化剂制备中的应用

本文对回转炉在催化剂工业化制备过程中的应用进行了探讨,并对其中的关键技术进行了详细分析,并对其在催化剂制备中的扩展应用和发展方向给出了建议。     

一种运动场地用聚氨酯涂料的制备

运动场地面层涂料为运动场地提供耐磨性和防滑性,需要具备出色的耐候性和稳定性。聚氨酯材料是目前使用最为广泛的运动场地涂料之一。以聚酯二元醇、聚醚多元醇、多异氰酸酯(—NCO)和二羟甲基丙酸(DMPA)等为原料,采用内乳化法制备一种运动场地用水性聚氨酯乳液,研究不同成分占比对涂料和成膜的影响。结果表明,随着异氰酸酯基团的增加,水基聚氨酯粒径增大,粘性减小,乳液涂膜后形成的聚氨酯薄膜拉伸强度增加,但弹性降低。随着扩链剂DMPA的增加,乳液的粒径减小,粘度增大,凝聚物减少,得到的聚氨酯薄膜致密性变好。