Heat-resistant Polymers Research Articles

Adhesive ability of a heat-resistant double-chain polymer and the strength of CFRP based on it

The adhesive ability of a heat-resistant polyiminoquinazolindione (PIQD) binder, based on a double-chain polymer, and the physicomechanical characteristics of unidirectional CFRPs made with it are investigated. It is shown that, at room temperature, the strength of model adhesive joints (PIQD-steel wire) and of the CFRPs in shear and bending is rather low — about half of that of similar specimens based on an epoxy binder. At the same time, all their mechanical characteristics, to a large measure (50%), are retained at temperatures up to 450°C, which considerably exceeds the heat resistance of all polymer matrices used at the present time. The elastic modulus of the CFRPs in bending practically remains the same up to 450°C.

Manufacture of high-strength composite materials from prepregs prepared by radiation processing

Scientific principles of the manufacture of high-strength heat-resistant polymer composite materials with the successive ionizing-radiation and heat treatment (via the step of long-lived prepregs) were developed. Methods for the selection of components for the preparation of long-lived prepregs, as well as for the determination of the optimal curing conditions, were proposed. The mechanical properties of the materials were studied.

High c-Axis Oriented Stand-Alone ZnO Self-Assembled Film

We developed a high c-axis oriented stand-alone ZnO self-assembled film. ZnO nanosheets were grown at the air–liquid interface to form a large ZnO film by Zn ion supply from an aqueous solution. The ZnO film had sufficiently high strength to freely stand alone and showed high c-axis orientation. The film can be pasted onto a desired substrate such as polymer films or a glass substrate. The novel process provides a low-cost, low-temperature method for forming high c-axis oriented stand-alone ZnO self-assembled films and coating them on low heat-resistant flexible polymer films.

Suspension polymerization and characterization of transparent poly(methyl methacrylate-co-isobornyl methacrylate)

A methacrylate copolymer based on isobornyl methacrylate (IBMA) and methyl methacrylate (MMA) was synthesized in an aqueous suspension via free-radical polymerization. The potential of this copolymer as a heatresistant optical polymer is also discussed. 1,1,3,3-tetramethylbutyl peroxy-2-ethyl hexanoate andn-octyl mercaptan were used as the initiator and chain transfer agents, respectively. The effect of IBMA on the properties of the copolymer was investigated. The composition of the copolymer was analyzed using1H-NMR, and the heat resistance by measuring the glass transition temperature, which exhibited a linear dependency on the IBMA content in the copolymer. Variation of the chain transfer content used in the synthesis step was effective for the optimization of the copolymer for practical use.

Modification of films of heat-resistant polyimides by adding hydrosilicate and carbon nanoparticles of various geometries

The possibility of modifying the properties of poly(4,4′-oxydiphenylene)pyromellitimide films by introducing into prepolymer solutions nanoparticles of various compositions and structures [hydrosilicate nanoparticles in the form of layered structures (montmorillonite) and nanotubes; carbon nanofibers] was examined. New intercalating agents, tetranuclear aromatic diamines, were suggested for pretreatment of montmorillonite prior to introduction into heat-resistant polymers. The mechanical characteristics of the nanocomposites with hydrosilicate nanotubes can be optimized by chemical pretreatment of the nanotubes prior to introduction into the polymer matrix. Introduction of the above-named nanoparticles into the polymer matrix appreciably increases the elastic modulus of the material. The largest increase in the elastic modulus is observed with hydrosilicate nanotubes of the chrysotile structure, coated with an aromatic modifier.

Electrical resistivity of sheet-type heaters with nanocarbon fillers

Sheet-type heaters were prepared using polyimide as a matrix with a mixture of two types of vapor-grown nanocarbon fillers, VGCF and cup-stacked carbon nanotubes (CSNT), and their electrical resistivity, thermal expansion and filler dispersion properties were evaluated. By using the heat resistant polymer, polyimide, it was expected that the positive temperature coefficient (PTC) effects appear at higher temperatures. The results showed that the nanocarbons were dispersed homogeneously and that the temperature dependence of the electrical resistivity could be controlled by the addition of two types of nanocarbon fillers. The optimum PTC properties were observed for the samples with the mixture of VGCF and CSNT at 30 wt % of total nanocarbons.

Structure, phase (aggregate) state, and optical properties of a new heat-resistant polymer with a nonlinear optical chromophore

A new heat-resistant copolymer (II) with a nonlinear optical chromophore in a side chain was synthesized by the etherification of side hydroxyl groups in chains of silicon-containing poly(o-hydroxyamide) (I) with 4′-{(6-chlorohexyl)methylamino}-4-nitroazobenzene (chromophore) under conditions of phase-transfer catalysis. The structure and phase (aggregate) states of copolymer II were investigated using x-ray diffraction and differential scanning calorimetry. It was shown that the substitution of chromophore molecules for up to 15% of hydrogen atoms in hydroxyl groups of amorphous copolymer I most likely leads to an independent arrangement of the chromophoric groups and the formation of crystal domains. It was established that this ordering substantially affects the stability and efficiency of the nonlinear optical properties of films prepared from copolymer II and is probably responsible for the slow decay of the second-harmonic generation signal in the sample.

Biomass-derived heat-resistant alicyclic hydrocarbon polymers: poly(terpenes) and their hydrogenated derivatives

Download options Please wait... Article information DOI https://doi.org/10.1039/B607789G Article type Paper Submitted 01 Jun 2006 Accepted 09 Aug 2006 First published 29 Aug 2006 Download Citation Green Chem., 2006,8, 878-882 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Biomass-derived heat-resistant alicyclic hydrocarbon polymers: poly(terpenes) and their hydrogenated derivatives K. Satoh, H. Sugiyama and M. Kamigaito, Green Chem., 2006, 8, 878 DOI: 10.1039/B607789G To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Kotaro Satoh Hiroko Sugiyama Masami Kamigaito

Strengthening of highly heat-resistant liquid-crystal polymer fibers upon heat treatment

Fibers of fully aromatic thermotropic liquid-crystal polymers containing mesogenic groups in the backbone are prepared on laboratory machines that make it possible to vary the conditions of jet spinning and subsequent heat treatment. The thermal and mechanical properties of the polymer fibers are investigated using differential thermal and thermomechanical analyses and strength measurements. It is found that, after spinning under optimum conditions, the strength of the fibers at room temperature is approximately equal to 1 GPa. After heat treatment under specially chosen conditions, the strength increases by a factor of two or three due to an increase in the activation energy of fracture. The role of crystallization and cross-linking in strengthening of liquid-crystal polymer fibers is elucidated.

Synthesis and characterization of photosensitive methacrylates to give heat-resistant polymers

New photosensitive monomers having multiple methacryloyloxy groups were synthesized by the reaction of naphthalene and biphenyl derivatives containing two or more glycidyloxy groups with methacrylic acid. The obtained photosensitive monomers were mixed with polymerization initiators (1 wt% AIBN and/or BIPE) and a reactive diluent (20 wt% DPCA60). The mixtures were termed as compounds. The compounds were converted into the insoluble gel products by heating or photo-irradiation with an ultra high-pressure mercury lamp. We also measured the heat resistance of the insoluble gel products by thermogravimetry and investigated the correlation between the heat resistance and the chemical structures of photosensitive methacrylate composites. All of the insoluble gel products showed the heat-resistance over 260 8C and particularly the compound having the largest number of methacryloyloxy groups had the highest heat-resistance among them. This compound exhibited the highest consumption rate of the photosensitive group and it was in accordance with the result of the reactive photo-polymerizability measured by the gray scale method.

P-23: Thin Durable Metal Substrates for High-Resolution a-Si TFT Active Matrix Displays

We have developed thin, durable and flexible, metal substrates for a-Si TFT active matrix displays. Fine-patterned a-Si TFTs can be fabricated using an Fe-Ni 42 alloy metal foil with a low coefficient of thermal expansion as the flexible substrate. The metal foil is coated using a heat-resistant polymer passivation layer, so that a conventional a-Si TFT process, where the maximum substrate temperature is 300 °C, can be applied. A 0.29mm-thick 200ppi 4″ VGA reflective LCD panel was realized using a 0.16mm thick metal substrate.

Influence of Allotropic Forms of Carbon on Formation and Cross-Linking of Heat-Resistant Polymer Binders

The thermochemical reactions of polyimide binder with various allotropic forms of carbon, fullerene C60 and ultradispersed artificial diamonds, were studied by thermal and spectral analyses.

Viscoelasticity of a Polymer Matrix and Fracture of Heat-Resistant Fiber Composites

This paper reports on the results of investigations into the general regularities of deformation and fracture of fiber composite materials based on new heat-resistant polymer binders. Fiber composites based on these binders can find wide application in various fields of engineering. It is established that an increase in the loss modulus of the polymer matrix decreases the probability of formation of a brittle crack in the matrix at the fiber break and increases the time interval between breakages of adjacent fibers. This leads to retardation of the correlated breakage of the fibers in fiber composite materials under loading, i.e., to an increase in their strength and fracture toughness. The inference is made that the matrix of high-strength heat-resistant fiber composites with a high fracture toughness should possess not only a high elasticity (this has long been known) but also good dissipative properties over the entire temperature range of operation.

Effect of Prolonged Ageing on the Mechanical Properties of a Number of Heat-resistant Polymers

Effect of Prolonged Ageing on the Mechanical Properties of a Number of Heat-resistant Polymers

放電プラズマ焼結法を用いた多機能クローズドセル構造金属材料の作製(J09-6 プロセス,J09 知的材料・構造システム)

Closed Cellular materials containing heat resistant polymer for smart systems has been developed. Heat resistant polymer particles coated with a nickel-phosphorus alloy layer using electroless plating were sintered by spark plasma sintering method. The compressive and damping tests were carried out to measure the mechanical and damping properties of this material, respectively. The results showed that the stress-strain curve had a liner region, long plateau region and wavy region, and the sintering temperatures of the specimens affected the compressive strength of each specimen. The damping capacity of this material were shown to be very large. These results indicate that this metallic closed cellular material can be utilized as a material for energy-absorbing and passive-damping systems.

Polymer-coated fibrous materials as the stationary phase in packed capillary gas chromatography.

Synthetic polymer filaments have been introduced as the support material in packed capillary gas chromatography (GC). The filaments of the heat-resistant polymers, Zylon, Kevlar, Nomex, and Technora, were longitudinally packed into a short fused-silica capillary, followed by the conventional coating process for open-tubular GC columns. The separation of several test mixtures such as n-alkylbenzenes and n-alkanes was carried out with these polymer-coated fiber-packed capillary columns. With the coating by various polymeric materials on the surface of these filaments, the retentivity was significantly improved over the parent fiber-packed column (without polymer coating) as well as a conventional open-tubular capillary of the same length. The results demonstrated a good combination of Zylon as the support and poly(dimethylsiloxane)-based materials as the coating liquid-phase for the successful GC separation of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), while successful applications for other separations such as poly(ethylene glycol) coating for the separation of alcohols were also obtained. From the results it has been suggested that the selectivity of the fiber-packed column could be tuned by selecting different coating materials, indicating the promising possibility for a novel usage of fine fibrous polymers as the support material that can be combined with newly synthesized coating materials specially designed for particular separations. Taking advantage of good thermal stability of the fibers, the column temperature could be elevated to higher than 350 degrees C with the combination of a short metallic capillary.

High Resolution in Heat-Resistant Optical Polymer by Electron-Beam Exposure and Thermal Development

A type of polyarylate (U100) with high glass-transition temperature (Tg: 193°C) has high optical transparency and thermal stability of refractive index and absorption. U100 can be processed by electron-beam (EB) exposure and thermal development. We study the optimum EB dose, temperature and time of thermal development, and film thickness, in order to achieve high-resolution processing in submicron size. We have successfully fabricated a high-resolution surface relief grating on the U100 thin film. The grating has the diffraction efficiency of 4.1%, and the efficiency did not change by heating for 100 h at 100°C.

Structure and optical properties of C60 films on polymer substrates

The results of investigations of the structure and optical properties of films of fullerene C60 are reported. The films were obtained by vacuum thermal evaporation on substrates from heat-resistant polymers (polyacrylonitrile and cyclized polyacrylonitrile in composition with polyimide). The structure of C60 films was determined by X-ray diffractometry. In all diffraction patterns of fullerene films, their structure manifests itself through reflections from the (111), (220), and (311) planes. Cubic C60 films were obtained by fullerene deposition at substrate temperatures as high as 200°C. Atomic force microscopy of the film surface revealed the existence of a laminated structure. The infrared (IR) transmission spectra are indicative of the presence and constancy of the position of characteristic bands of C60 (527, 576, 1183, and 1428 cm−1) for all fullerene films. The investigation of photoluminescence of fullerene films revealed bands whose energy position both exceeded typical values for molecular C60 or fell below these values. This circumstance is caused by the interaction between the electron π systems of C60 and the polymer substrate at the heterointerface, as well as by the photopolymerization reaction of fullerene under the effect of high-energy laser radiation and by the emergence of trap centers in the films.

120 耐熱ポリマーを内包する 3 次元マイクロハニカム構造金属材料の作製

A metallic 3-dimentional micro-honeycomb structural material containing heat resistant polymer for smart systems has been developed. Heat resistant polymer particles coated with a nickel-phosphorus alloy layer using electroless plating were pressed into green pellets and sintered at high temperatures in a vacuum. A metallic 3-dimentional micro-honeycomb structural material containing heat resistant polymer was then fabricated. The compressive and damping tests were carried out to measure the mechanical and damping properties of this material, respectively. The results showed that the stress-strain curve had a liner region, long plateau region and wavy region, and the sintering temperatures of the specimens affected the compressive strength of each specimen. The damping capacity of this material were shown to be very large. These results indicate that this metallic closed cellular material can be utilized as a material for energy-absorbing and passive-damping systems.

227 触媒バグフィルタの開発(第 1 報) : 繊維状触媒の開発とバグフィルタへの適用

We developed the fibrous catalysts which had high activity in decomposition of organic chlorine compounds and reduction of NO by NH_3. The catalyst fiber composed of V_2O_5 and TiO_2 exhibited favorable structural properties (large specific surface area of more than 200m^2/g and large pore volume of more than 0.20(cm)^3/g) and capability to stabilize V_2O_5 in a well dispersed form up to high loading. A catalytic bag filter was produced by placing a layer of the catalyst fiber within a nonwoven fabric of heat resistant polymer fiber.