Vulcanization and Vulcanizate Properties of a Fluoroelastomer Containing Epoxy Groups as Cure Sites

1981 ◽  
Vol 54 (4) ◽  
pp. 779-796 ◽  
Author(s):  
G. Kojima ◽  
H. Kojima ◽  
M. Morozumi ◽  
H. Wachi ◽  
M. Hlsasue

Abstract The vulcanization behavior and vulcanizate properties of tetrafluoroethylene-propylene elastomer containing a small amount of glycidyl vinyl ether as cure site was investigated both at room temperature and at high temperature with different types of the vulcanizing agents. The conclusions are: 1. Glycidyl vinyl ether incorporates into the tetrafluoroethylene-propylene copolymerization system without disturbing the alternating microstructure and works as an efficient cure site. 2. The room-temperature vulcanization of the terpolymer proceeds at an adequate rate when tris(dimethylaminomethyl)phenol is used as the curative together with phenol as the accelerating agent. 3. Coatings of the terpolymer make a tough finish on many substrates such as steel and hydrocarbon rubbers and protect the substrates from hostile environments. 4. The vulcanization behavior of the terpolymer at high temperature is much influenced by the kind of curative. The carboxylate of hexamethylenediamine [e.g., hexamethylenediamine-N,N′-bis(p-isopropylbenzoate)] provides balanced vulcanization behavior and mechanical properties suitable for molding articles of complex shapes. 5. The mechanical and chemical properties of the high-temperature vulcanizate thus obtained are similar to those of the tetrafluoroethylene-propylene binary system vulcanized by peroxide.

Author(s):  
Patrice Berthod

Superalloys are metallic alloys with specific microstructures and atoms in solid solution allowing good mechanical and chemical properties at high temperature, typically higher than 1000°C. They present many different types of {matrix – precipitates} combinations which can be characterized at each step of their elaboration, by specifying the chemical compositions and the crystalline network of the phases present. After test on a sample (laboratory scale), or after the deterioration in service of a component leading to its replacement by a new one (industrial scale), the superalloys constituting these pieces are often usefully examined. This aims to specify the changes occurred in their microstructures as well as in their surface or sub-surface, due to the endured thermal, mechanical and chemical solicitations. These characterizations can be simply done using basic low-magnification optical microscopic examinations. Other means such as electronic microscopy and other advanced apparatus may be usefully involved for further investigations. After a brief history about superalloys, an overview of the phenomenological aspects of their mechanical and chemical solicitations during their use at high temperature, the metallographic techniques which are usually employed to characterize them are presented and illustrated in the case of a chosen family of superalloys.


Author(s):  
Hongtao Liu ◽  
Yiyang Liu ◽  
Tao Su

Molten salts were widely used in nuclear and solar power field due to the excellent heat transfer and storage. Molten fluoride salts were selected as primary and secondary coolants in the Molten Salt Reactor Experiment (MSRE) developed by Oak Ridge National Laboratory (ORNL). Therefore, it is dramatically important to study the physical and chemical properties of molten fluoride salts that impact on the design of reactor core and thermohydraulics. The molecular structure directly determines the physical and chemical properties of matter, so it is also essential to study the structure of molten salts. Spectroscopy has been proven to be a very useful tool for investigating molten salts structures. However, the standard instrument is inapplicable for measurement of the high temperature molten salts, especially for molten fluoride salts. To obtain the ultraviolet-visible (UV-Vis) absorption spectra of molten salts at high temperature, an instrument was designed to study the structures of molten salts in situ. The instrument is mainly composed of a vertical pit furnace connecting with a glovebox and an assembled cuvette which can operate from room temperature up to 800°C. The assembled cuvette is made of Hastelloy C/N as the main body with a reverse ‘T’ contour and diamond or crystalline CaF2 etc. as the window plates, so it can withstand the corrosion produced by the sample and allow the interest light passing through. The effective spectral range of this instrument is from 200 to 1000 nm. Performances of the instrument are testified by spectral studies on water under room temperature and molten salts under high temperature.


2019 ◽  
Vol 2 (3) ◽  
pp. 148-156
Author(s):  
Amrosius Masrikat ◽  
Yohansli Noya ◽  
Hendry Izaac Elim

Kian sandworm (Siphonosoma ur-pulau), a kind of sandworm originally found in Ur-pulau island of Tual region, southeast part of Maluku province, Indonesia is one of the longest sand worm with the length of 27.5 cm exhibited unique physical and chemical properties [1]. This work presents image processing and optical-electricity property of traditional medicine products (TMPs) from Kian sandworm. Based on the image processing with fast Fourier transform (FFT) technique, the density of two different types of TMPs can be identified exactly. Furthermore, optical-electricity (OE) properties of the products tested in a standard toxic medicine, Betadine normally used to heal outer wounds of human body in Indonesia has been studied briefly under the influence of room temperature up to ~65 0C. The significant findings in this paper show that at the same concentration of two TMPs, the smooth grain size exhibits large absorbance (Abs) and pH higher than that of the rough grain size due to its high density. Moreover, it was observed that such smooth grain size TMPs shown a very sensitive voltage dependence on temperature with the peak of voltage obtained at ~50 0C.


2014 ◽  
Vol 521 ◽  
pp. 658-661
Author(s):  
Lei Yang ◽  
Shang Guan Ju ◽  
Yu Kun Gao ◽  
Yan Hui Hu

Physical and chemical properties are closely related to desulfurization, regeneration performance and cycle stability for high temperature coal gas desulfurizer. This review focuses on influence rules of changes in regeneration atmosphere, temperature and space velocity on physical and chemical properties. A large number of experimental researches have shown that regeneration atmosphere, regeneration temperature, space velocity have an important influence on mechanical strength, active component and texture change for high temperature coal gas desulfurizer. The different regeneration atmosphere obviously results in different active ingredients for desulfurization sorbent after regeneration, and regeneration at a higher regeneration temperature will easily cause desulfurizer sintering, as well as small regeneration space velocity can lead to the formation of sulfates. In order to make the circulatory system of sulfidation-regeneration-sulfidation need to the requirements in industrial application, the further research of influence rules of regeneration condition on physical and chemical properties will be crucial.


2011 ◽  
Vol 287-290 ◽  
pp. 294-297
Author(s):  
Cui Zhi Dong ◽  
Li Fang Zhang ◽  
Xiao Yan Wang ◽  
Ming Xi Zhang ◽  
Zhi Min Cui ◽  
...  

Because of the good photoelectric learning properties and chemical properties, CdTe nanocrystalline as an important Ⅱ-Ⅵ clan semiconductor materials has been used in LEDs, photonics, in aspects of materials and biomarker and so on. W/O microemulsion method has the peculiarity of tester simpleness, easy manipulation, room temperature react etc. In this paper CdTe nanoparticles was synthesized in CTAB/cyclohexane/isobutanol/water quatemary microemulsion system in alkaline condition and nitrogen. The morphology of the final products were characterized by X-ray power diffraction, transmission electron microscopy. according to the means, this paper researches the effect of surfactant contentration to morphology. The result is that the different morphology can be obtained through the different CTAB concentration. Finally, according to TEM chart, this paper infers the formation mechanism of the CdTe.


1987 ◽  
Vol 105 ◽  
Author(s):  
Takuji Goda ◽  
Hirotsugu Nagayama ◽  
Akihiro Hishinuma ◽  
Hideo Kawahara

AbstractA new coating process of silicon dioxide (SiO2) “LPD” process, has been developed recently. Silicon dioxide (SiO2) film can be deposited on any substrate at the room temperature by immersing in hexafluorosilicic acid (H2SiF6).In this study, physical and chemical properties of the “LPD- SiO2” film were investigated by using XPS, IR, ellipsometry, and etch rate measurement. The properties of this film deposited at the room temperature were almost the same as those of plasma CVD. The “LPD-SiO2” film without annealing was contained traces of F and OH. However, by annealing, F and OH were rapidly evaporated from the film and the film was getting densified.As the “LPD-SiO2” film deposited at the room temperature showed very good results of chemical etching rate and of step coverage, it is expected that it is possible to use this “LPD- SiO2” film in the wide range of industrial area.


2018 ◽  
Vol 115 (2) ◽  
pp. 209
Author(s):  
Debjani Nag ◽  
P. Kopparthi ◽  
P.S. Dash ◽  
V.K. Saxena ◽  
S. Chandra

Macerals in coal are of different types: reactive and inert. These macerals are differ in their physical and chemical properties. Column flotation method has been used to separate the reactive macerals in a non-coking coal. The enriched coal is then characterized in order to understand the changes in the coking potential by different techniques. It is then used in making of metallurgical coke by proper blending with other coals. Enriched coal enhance the properties of metallurgical coke. This shows a path of utilization of non-coking coal in metallurgical coke making.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yadian Xie ◽  
Duygu Kocaefe ◽  
Chunying Chen ◽  
Yasar Kocaefe

The nanomaterials have been widely used in various fields, such as photonics, catalysis, and adsorption, because of their unique physical and chemical properties. Therefore, their production methods are of utmost importance. Compared with traditional synthetic methods, the template method can effectively control the morphology, particle size, and structure during the preparation of nanomaterials, which is an effective method for their synthesis. The key for the template method is to choose different templates, which are divided into hard template and soft template according to their different structures. In this paper, the effects of different types of templates on the morphology of nanomaterials during their preparation are investigated from two aspects: hard template and soft template, combined with the mechanism of action.


2013 ◽  
Vol 465-466 ◽  
pp. 76-80
Author(s):  
Nor Hafiez Mohamad Nor ◽  
Ismail Muhammad Hussain ◽  
Nur Atikah Abu Kasim ◽  
Wan Dung Teng ◽  
M.K. Idham

Aluminium alloys is widely applied in heat sink but its application of heat absorption is still unsatisfied. While, Aluminum Nitride (AIN) was discovered as another option for heat sink application because of its great thermal conductivity and it also has high electrical conductivity at high temperature. Thus, the mechanical and chemical properties of a sintered mixed powder of Alumina and AIN are investigated experimentally. There are five different compositions of mixed powder of Alumina-AIN and sintered at three different sintering temperatures which are 1400°C, 1500°C and 1600°C. As applying a high sintering temperature on samples inducted great flexural strength and increase it modulus of rupture. High sintering temperature (1600°C) also affected the materials microstructure as the particle was arranged closely between each other and reduces the amount of porosity. The application of high temperature in the mixture of AIN with Alumina reduces the occurrence of flaws like cracking and accordingly improves the strength. These combination of Alumina-AIN brought acceptable result in thermal conductivity value analysis and as well enhancing the thermal conductivity.


2016 ◽  
Vol 1 (1) ◽  
pp. 29 ◽  
Author(s):  
Mohammad Asif

Pyridopyridazine compounds are important nitrogen atom containing heterocyclic compounds due to their pharmacological versatility. This heterocycle system characterized a structural feature for different types of bioactive compounds that exhibiting various types of biological activities which make it an attractive scaffold for the design and development of new drug molecules. This article provided information about the pharmacological properties of pyridopyridazines derivatives.


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