Carbon-reinforced plastics based on hybrid polyimide-organosilicon binders

Compounds based on the synthesized polyimides and organosilicon resins were developed. The compatibility of organosilicon resins with polyimide binders was studied by electron microscopy. The possibility of preparing fibrous composite materials, carbon-reinforced plastics, using such polyimide-organosilicon binders was demonstrated. The viscoelastic and strength properties of the materials obtained were studied. The optimum binder composition, ensuring 90% preservation of the elastic modulus and 70% preservation of strength of the carbon-reinforced plastic relative to the initial values after keeping in air for 50 h at 350°C, was chosen.     

含氟聚酰亚胺及其在微电子工业中的研究进展Ⅱ含氟聚酰亚胺在微电子工业中的应用

综述了近年来国内外在含氟聚酰亚胺(PI)研究及应用领域中的最新进展情况。主要从现代微电子工业对相关材料的性能要求、标准型聚酰亚胺材料所面临的挑战以及新型含氟聚酰亚胺在微电子工业中的应用等几个方面进行了详细的综述。重点阐述了中国科学院化学研究所305组近几年在这方面的研究进展情况。并指出为了推动我国微电子工业的发展，研制开发低成本、高技术含量的含氟聚酰亚胺材料具有十分重要的现实意义．     

A review on the latest development of carbon membranes for gas separation

Inorganic membranes have been developed before 1945. The earlier application of inorganic membranes was primarily concentrate on military purpose. Carbon membrane is one type of porous inorganic membrane. Although the concept of carbon membrane for gas separation has been found in the early 1970, the interest to develop carbon membrane only increased, since Koresh and Soffer successfully prepared apparently crack-free molecular sieving hollow fiber carbon membranes. Nowadays, plenty of researchers have used different polymeric materials; including polyimides, to prepare carbon membranes by using pyrolysis. In general, carbon membranes can be divided into four major configurations: flat sheet, membrane supported on tube, capillary, and hollow fiber. Permeation properties of carbon membranes have been improved greatly in these 20 years. Carbon membranes offer advantages over polymeric membranes especially in terms of selectivity as well as thermal and chemical stability. More attention will be paid to carbon membranes in this century. This paper will review the development of carbon membranes in the last 30 years and give a clear future direction in research for carbon membrane.     

苯乙炔基封端聚酰亚胺材料研究进展

在过去二十年中，芳香族聚酰亚胺材料得到越来越广泛的应用，其中苯乙炔基封端的聚酰亚胺材料因其优异的性能成为目前耐高温聚合物材料研究的热点。本文综述了苯乙炔基封端聚酰亚胺材料的研究现状与发展趋势，着重对材料的化学结构设计与制备方法、以及化学结构与性能之间的关系进行介绍。     

Polymer microfabrication technologies for microfluidic systems

Polymers have assumed the leading role as substrate materials for microfluidic devices in recent years. They offer a broad range of material parameters as well as material and surface chemical properties which enable microscopic design features that cannot be realised by any other class of materials. A similar range of fabrication technologies exist to generate microfluidic devices from these materials. This review will introduce the currently relevant microfabrication technologies such as replication methods like hot embossing, injection molding, microthermoforming and casting as well as photodefining methods like lithography and laser ablation for microfluidic systems and discuss academic and industrial considerations for their use. A section on back-end processing completes the overview.     

含氟聚酰亚胺及其在微电子工业中的研究进展I含氟单体及聚酰亚胺的合成

综述了近年来国内外在含氟聚酰亚胺(PI)研究及应用领域中的最新进展情况。主要从含氟二胺单体、二酐单体及含氟聚酰亚胺在合成方面的研究进展情况进行了详细的综述。重点阐述了中国科学院化学研究所305组近几年在这方面的研究进展情况，并指出为了推动含氟聚酰亚胺这类具有优良综合性能的功能材料在工业上的广泛应用，就必须首先解决含氟单体种类较少这个制约含氟聚酰亚胺发展的瓶颈问题。     

Polymers for microlithographic applications: new directions and challenges

Advances in the fabrication technologies associated with electronic devices have placed increasing demands on microlithography, the technology used to generate today's integrated circuits. Within the next few years, a new form of lithography will be required that routinely produces features of less than 0.1 μm. As the exposing wavelength of light decreases to facilitate higher resolution imaging, the opacity of traditional materials precludes their use; and major research efforts to develop alternate materials are underway. As a current example, lithography tools utilizing 193 nm light are now being introduced into the manufacturing environment. Through understanding of materials structure and its relationship to device process requirements and performance, a new class of cyclo‐olefin based polymers was designed for these applications. In particular, alicyclic monomers such as norbornene are readily copolymerized with maleic anhydride and substituted acrylates to afford a wide range of alternative matrices that exhibit transparency at the exposing wavelength and aqueous base solubility. Materials properties must be carefully tailored to maximize lithographic performance with minimal sacrifice of other performance attributes. Further reduction in exposing wavelength to 157 nm introduces new challenges in polymer materials design. Efforts to address those challenges will be discussed.     

聚酰亚胺研究新进展

聚酰亚胺（PI）是一类重要的高性能聚合物,广泛应用在航空航天、微电子、汽车、石油等高科技领域。由于其结构上的可设计性,世界上越来越多的研究者投入到这类高技术材料的研究开发中。本文分别从可溶性PI的分子设计与合成、功能性PI的合成与用途、PI绿色合成方法、PI纳米复合材料的制备4个方面综述了近年来PI的研究热点和新进展,为了解聚酰亚胺的研究提供了有价值的信息。     

Reaction mechanism and products of the thermal conversion of hydroxy-containing polyimides

Thermal treatments of hydroxyl-containing polyimide materials at high temperatures are believed to lead to unique structural and chemical changes to the polymer backbone and side groups. These rearrangements when applied to specific polymeric membranes improve both their permeability and selectivity over conventional materials and this development has been attributed to the formation of nanoporous cavities in the treated products. However, the mechanisms of the possible chemical reactions that take place and the structures of the end-products have been poorly understood. With validated evidence from experiments and virtual screening of different precursors and possible products by molecular simulation, we have determined that hydroxy-containing polyimides can be thermally rearranged into poly(biphenylene bisimide) polymers under designed conditions. The proposed reaction mechanism is novel and calls into question the previously reported polybenzoxazole mechanism of thermal rearrangement. The new results indicate that the exact conditions of synthesis and thermal treatment of the starting polyimides will be critical to the properties of the membranes produced.     

光致发光聚酰亚胺研究进展

聚酰亚胺是一类重要的高性能高分子材料,具有优异的热性能、机械性能、电学性能和尺寸稳定性等,同时具有良好的结构可设计性,已逐渐成为有机光电领域的研究热点.然而,传统聚酰亚胺材料一般不发光,文献中有关发光聚酰亚胺的研究并不多.同时,所报道的荧光量子产率普遍较低,极大地限制了其作为发光功能层在有机光电器件领域的应用.为了更好地了解聚酰亚胺发光的规律,拓展高性能聚酰亚胺材料在有机发光器件中的应用领域,本文介绍了聚酰亚胺光致发光的机理,综述了国内外有关光致发光聚酰亚胺的研究进展,总结了提高聚酰亚胺荧光量子产率的方法,并对未来高性能高效发光聚酰亚胺材料的研究方向做了展望.     

New Soluble Fluorinated Polyimides

Aromatic polyimides have been widely used in aerospace, electrical and electronic applications due to their outstanding thermal stability, mechanical strength at elevated temperature and electrical properties1-3. However, polyimide materials are usually difficulty to fabricate owing to their insolubility in most organic solvents and infusibility. Besides solubility, low moisture uptake of polyimide is also a major concern for microelectronics and optical applications. The present article descr…     

Synthesis and optical properties of polyimides

Polyimides are important industrial materials because of their excellent properties. They are extensively used in the electronics industry and have great potential in the field of optical communications. In this article, we discuss the effect of the polyimide structure and the processing conditions on the optical properties. Both commercially available fluorinated polyimides and polyimides synthesized in our laboratory were used in this study. The relationship between the extent of fluorination and the refractive index was studied, and it was found that fluorination reduced the refractive index as expected. Studies conducted on the structure–property relationship revealed that with the use of more rigid monomers for the polyimides, the polyimides could be modified to show a large birefringence. The extent of birefringence depended on the composition of the polymer. In addition, the processing conditions directly controlled the residual stress in the polymer films. The residual stress was an important factor in inducing light scattering, which resulted in higher optical loss. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4832–4838, 2000     

Recent advances in photosensitive polyimides

The state of the art of photosensitive polyimides is reviewed with respect to the incorporation of photosensitivity into both polyimide precursors and soluble polyimides, for patterning in positive and negative modes. This paper emphasizes, in particular, the discussion of the performance of commercially available photosensitive polyimides with respect to their applications in electronics. The decisive properties, especially the patterning performance, and in the case of precursors the curing conditions, required to obtain full imidization, thermomechanical and electrical properties, solvent resistance and water uptake, as well as planarization of the commercially available materials, are compared with each other. An outlook presents the future demands on photosensitive polyimides.     

Thermal stability of 6FDA-(co-)polyimides containing carboxylic acid groups

Different (co-)polyimides with and without carboxylic acid groups have been synthesized, characterized and thin films have been prepared. Aging as well as degradation effects at temperatures up to 380 °C have been investigated in order to determine whether high temperature applications are possible. Thus this work was focused on aromatic fluorinated polyimides and copolyimides derived from 6FDA (4,4′-hexafluoroisopropylidene diphthalic anhydride), 4MPD (2,3,5,6-tetramethyl-1,4-phenylene diamine) and DABA (3,5-diamino benzoic acid), since 6FDA-(co-)polyimides are well known for high stability and superior processability. Aging processes have been analyzed using infrared spectroscopy, density measurements and thermogravimetric analysis. It has been found that up to 380 °C the synthesized materials show minor weight losses and aging effects but remain mechanically stable. On the one hand some properties like colour and solubility changed but on the other hand gas separation characteristics could be improved. In all cases structure and mechanical stability persisted after heat treatment. The analytical results lead to the conclusion that the synthesized materials can be used as high performance polymers in various applications, i.e. hydrogen fuel cell and aerospace applications.     

Recent advances in high surface area electrodes for bioelectrochemical applications

The search for high surface area electrodes for bioelectrochemical applications is becoming more intense. In the last few years, new strategies have emerged to develop three-dimensional electrode materials with very well controlled architecture providing at the same time high specific surface, bendability and flexibility. This review will highlight some of the recent work published in the last 2 years and will discuss the issue of mathematical modeling of porous electrodes and what could be the future of high surface area electrodes materials.     

Beyond the Capture of Circulating Tumor Cells: Next‐Generation Devices and Materials

Over the last decade, significant progress has been made towards the development of approaches that enable the capture of rare circulating tumor cells (CTCs) from the blood of cancer patients, a critical capability for noninvasive tumor profiling. These advances have leveraged new insights in materials chemistry and microfluidics and allowed the capture and enumeration of CTCs with unprecedented sensitivity. However, it has become increasingly clear that simply capturing and counting tumor cells launched into the bloodstream may not provide the information needed to advance our understanding of the biology of these rare cells, or to allow us to better exploit them in medicine. A variety of advances have now emerged demonstrating that more information can be extracted from CTCs with next‐generation devices and materials featuring tailored physical and chemical properties. In this Minireview, the last ten years of work in this area will be discussed, with an emphasis on the groundbreaking work of the last five years, during which the focus has moved beyond the simple capture of CTCs and gravitated towards approaches that enable in‐depth analysis.     

Selection of membrane materials for separation of H2-containing mixtures: Database analysis

Correlation between the chemical structure and transport characteristics of polyimides that are used for separation of hydrogen-containing mixtures is analyzed. The effect of various functional groups (keto-, oxy-, methoxy-, amino-, and others) in polyimides is considered in detail. The group-contribution method is demonstrated to be efficient for prediction of the transport properties of new polyimides and for the search for new promising diamine-dianhydride combinations. The empirical analysis of the database accumulated at the Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, confirms the perspectiveness of further investigations of new membrane materials for separation of H₂-CH₄ and H₂-CO gas pairs.     

A MOLECULAR APPROACH TO THE SYNTHESIS OF NOVEL POLYIMIDES*

In the past ten years there has been a flurry of activity in the synthesis of new specialty polymers,largely as a result of the increased need for high technology materials. Interest is mainly shown in two distinctcategories of polymers: a) polymers which are used in very small quantities to fulfill critical needs as a part ofdevice systems, and b) high-performance engineering polymers which significantly extend their mechanicaland thermal properties for structural applications. Polyimides and their unparalleled versatility have capturedthe attention and imagination of scientists and engineers. This article describes some of the recent work doneby the author's group on the rational design at the molecular level and the synthesis of polyimides that haveunusual structures and novel properties.     

Fluorescent nanoprobes dedicated to in vivo imaging: from preclinical validations to clinical translation

With the fast development, in the last ten years, of a large choice of set-ups dedicated to routine in vivo measurements in rodents, fluorescence imaging techniques are becoming essential tools in preclinical studies. Human clinical uses for diagnostic and image-guided surgery are also emerging. In comparison to low-molecular weight organic dyes, the use of fluorescent nanoprobes can improve both the signal sensitivity (better in vivo optical properties) and the fluorescence biodistribution (passive "nano" uptake in tumours for instance). A wide range of fluorescent nanoprobes have been designed and tested in preclinical studies for the last few years. They will be reviewed and discussed considering the obstacles that need to be overcome for their potential everyday use in clinics. The conjugation of fluorescence imaging with the benefits of nanotechnology should open the way to new medical applications in the near future.     

POLYIMIDES,POLYQUINOLINES AND POLYQUINOXALINES: Tg-STRUCTURE RELATIONSHIPS

Abstract

Since polyimides were invented more than 30 years ago, several books dealing with the subject have been published [33, 34, 40u, 48b, 55, 64]. While some of these books [33–35] have very thorough and systematic coverage of the chemistry and general physical, mechanical, and electrical properties of polyimides, most of the literature [40, 48b, 64] is made up of collections of results derived from application-related research on various polyimides. None of the earlier treatises is totally devoted to an understanding of the underlying principles involved in just a single, important property such as the glass transition temperatures of polyimides.