Mechanism of the thermal transformations of polyacrylonitrile fibres in oxidation

Кошелев, Ю В; Sokolovskii, V. N.; Kotorlenko, L. A.; Plygan, E. P.; Сергеев, В. П.

doi:10.1007/bf00551622

Cited by 5 publications

(2 citation statements)

References 4 publications

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“…The decrease in the strong nitrile and methylene absorption bands was correlated with the extent of cyclization and dehydrogenation, respectively. Appearance of a shoulder at 2180 cm −1 due to nitrile group conjugated with CC groups and weak bands at 1665 and 1680 cm −1 pertaining to CCCN and CNCN confirms the cyclization reaction through nitrile groups 34…”

Section: Introductionmentioning

confidence: 76%

Thermal behavior of acrylonitrile carboxylic acid copolymers

Bahrami

Bajaj²,

Sen³

2003

J of Applied Polymer Sci

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Polyacrylonitrile (PAN) and copolymer of acrylonitrile-vinyl acids prepared by solution polymerization technique have been characterized by Differential Scanning Calorimetry (DSC) (under dynamic as well as isothermal conditions), themograviemetric analysis (TGA), and online DSC-FTIR spectroscopy. The DSC of copolymers was carried out at 5°C/min in nitrogen and air. In nitrogen atmosphere the DSC exotherm show a very sharp peak, whereas, in air atmosphere DSC exotherm is broad, and starts at a much lower temperature compared to what is observed in nitrogen atmosphere. The initiation temperature of PAN homopolymer is higher than that for the copolymers. For instance, the initiation temperature of PAN in air is 244°C, whereas, the onset of exothermic reaction is in the range of 172 to 218°C for acrylonitrile-vinyl acid copolymers. As the vinyl acid content increases the ⌬H value reduces. The ⌬H value of PAN in air was 7025 J/g, whereas, for P(AN-AA) with 5.51 mol % of acid it was 3798 J/g. As the content of acrylic acid comonomer is increased to 17.51 mol % the value of ⌬H decreases further to 1636 J/g. The same trend was observed with MAA and IA as well. DSC-FTIR studies depict various chemical changes taking place during heat treatment of these copolymers.

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Section: Introductionmentioning

confidence: 76%

Thermal behavior of acrylonitrile carboxylic acid copolymers

Bahrami

Bajaj²,

Sen³

2003

J of Applied Polymer Sci

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“…Basically, the stabilization process performed in carbon membrane preparation is also similar to the stabilization process carried out in carbon fiber preparation. During the stabilization process, the precursor would undergo a number of physical and chemical changes due to a variety of exothermic chemical reaction, including decomposition, dehydrogenation, oxidation, and crosslinking 35,36. In this study, carbon membrane derived from polymer blend of PEI/PVP in self‐supporting form for CO 2 separation were prepared.…”

Section: Introductionmentioning

confidence: 99%

Effect of stabilization temperature on gas permeation properties of carbon hollow fiber membrane

Salleh

Ismail

2012

J of Applied Polymer Sci

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Carbon hollow fiber membranes (CHFMs) derived from polymer blend of polyetherimide (PEI) and polyvinylpyrrolidone (PVP) were extensively prepared through stabilization under air atmosphere followed by carbonization under N2 atmosphere. The effects of the stabilization temperature on the morphological structure, chemical structure, and gas permeation properties were investigated thoroughly by means of scanning electron microscopy, Fourier transform infrared spectroscopy, and single gas permeation system. The experiment results indicate that the transport mechanism of small gas molecules of N2, CO2, and CH4 is dominated by the molecular sieving effect. Based on morphological structure and gas permeation properties, an optimum stabilization condition for the preparation of CHFM derived from PEI/PVP was found at 300°C under air atmosphere. The selectivity of ˜55 and 41 for CO2/CH4 and CO2/N2, respectively, were obtained for CHFMs prepared at stabilization temperature of 300°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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Carbon Membranes

Ismail¹,

Salleh²

2013

Encyclopedia of Membrane Science and Technology

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Carbon membranes are considered a relatively new addition to the mainstream of membrane material research. The significant number of publications in recent years shows the tremendous growth and development efforts in this research field. Carbon membranes can be fabricated by heat treatment from various types of polymeric precursor membranes such as polyimides and derivatives, polyacrylonitrile, phenolic resin, polyacrylonitrile (PAN), polyfurfuryl alcohol (PFA), polyetherimide (PEI), polyphenylene oxide (PPO), polyvinylidene chloride (PVDC), and polyphthalazinone ether sulfone ketone (PPESK). Carbon membranes can be divided into two categories, namely, supported and unsupported. The typical characterization methods used for carbon membranes can be classified into membrane performance evaluation and physical characterization. Physical characterization includes thermogravimetry analysis (TGA), X‐ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), adsorption and sorption experiments, and elemental analysis. A further explanation of each process parameter to obtain carbon membranes of highest quality is provided. In addition, the performances of various types of carbon membranes developed by previous researchers for different gas separation applications are also summarized. Furthermore, the potential applications and future directions of carbon membranes in gas separation processes are identified in this review. Other potential processes for carbon membranes including pervaporation, water treatment, and membrane reactor are also emphasized. Although significant research has been conducted since the development of carbon membranes, the need to extensively improve the gas permeation properties of these membranes still remains important if it is to become a viable membrane material for industrial applications.

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Mechanism of the thermal transformations of polyacrylonitrile fibres in oxidation

Cited by 5 publications

References 4 publications

Thermal behavior of acrylonitrile carboxylic acid copolymers

Thermal behavior of acrylonitrile carboxylic acid copolymers

Effect of stabilization temperature on gas permeation properties of carbon hollow fiber membrane

Carbon Membranes

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