Thermal behaviour of acrylonitrile copolymers having methacrylic and itaconic acid comonomers

Bajaj, P.; Sreekumar, T. V.; Sen, Kushal

doi:10.1016/s0032-3861(00)00583-8

Cited by 193 publications

(118 citation statements)

References 25 publications

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“…An onset temperature was 280.6˚C, and the curves completed at 307.4˚C (Figure 3(a)). It is known that compared to itaconic acid modified PAN, which can have two separated peaks due to ionic and free radical mechanism, pure PAN fiber is cyclized only by a free radical mechanism, revealing one peak [15]. The similar peaks were observed with stabilized fibers for 5 and 10 min.…”

Section: Thermal Behavior Of Stabilized Pan Fibersmentioning

confidence: 56%

Structural Evolution of Polyacrylonitrile Fibers in Stabilization and Carbonization

Lee¹,

Kim²,

Ku³

et al. 2012

ACES

201

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The effect of structural evolution polyacrylonitrile (PAN) on mechanical properties was investigated in stabilization and carbonization. PAN spun fibers were stabilized in a convection oven with a constant tension for various times at 250˚C. Fourier Transform Infrared spectroscopy (FTIR) and gel fraction results suggested that intra and intermolecular stabilization reactions occurred simultaneously. X-ray diffractograms revealed a disruption of crystalline structure and an appearance of pre-graphitic structure of PAN fibers due to stabilization. These structural changes by stabilization resulted in the significant decrease of tensile properties of fibers. In Raman spectra with heat treated fibers from 400˚C up to 1200˚C, the intensity ratio of the D to G bands (I D /I G ) decreased as heat treatment temperature increased, indicating an increase of basal plane of graphitic layer of heat treated fibers. Tensile strength of heat treated fibers at 1200˚C was found to be as high as 2.2 GPa.

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Section: Thermal Behavior Of Stabilized Pan Fibersmentioning

confidence: 56%

Structural Evolution of Polyacrylonitrile Fibers in Stabilization and Carbonization

Lee¹,

Kim²,

Ku³

et al. 2012

ACES

201

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“…The first step is up to about 250 °C, where weight loss is very small. In combination with the DSC results, it is inferred that there is only cyclization occurring in this step, since this reaction theoretically does not cause any weight loss [46]. The second step is up to about 300 °C.…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 57%

Photoactive Polyacrylonitrile Fibers Coated by Nano-Sized Titanium Dioxide: Synthesis, Characterization, Thermal Investigation

Moafi

Shojaie

Zanjanchi

2011

J. Chil. Chem. Soc.

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Anatase nanocrystals were successfully synthesized and deposited onto polyacrylonitrile fibers with photocatalytic self-cleaning activity using the sol-gel process at low temperature. The original and treated samples have been characterized by several techniques such as scanning electron microscopy, fourier transform infrared spectroscopy, x-ray diffraction, diffuse reflectance spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The TiO 2 nanoparticles, have been found to form a homogeneous thin film on the fiber surface. The photocatalytic activity, tested by measuring the degradation of adsorbed Eosin Yellowish dye. The photoactivity of the titanium dioxide coated fibres is much higher than that observed in case of untreated fibers. The photocatalytic selfcleaning properties of the treated fibers was fully maintained performing several cycles of photodegradation. This preparation technique can be also applied to new fabrics to create self-cleaning properties in them. The thermogravimetric study of PAN/TiO 2 composite showed a slight increase of weight loss in the second step, which implied that, the dehydrogenation and oxygen uptake reactions would be promoted by the TiO 2 to some extent.Keywords: Polyacrylonitrile; Titanium dioxide; Thermogravimetric analysis; Differential scanning calorimetry; Photodegradation; Eosin Yellowish e-mail: Shalkeh737@gmail.com INTRODUTIONPolyacrylonitrile (PAN) is one of the most widely used precursor polymers for making high performance carbon fibers [1][2][3][4][5]. Study of the degradation of polyacrylonitrile has been a subject of interest for decades owing to its commercial value for the production of carbon fibers [6][7][8][9][10]. Spectroscopy, including infrared, ultraviolet, solid-state nuclear magnetic resonance (NMR) and x-ray photoelectron spectroscopy (XPS), and thermal analysis, including differential scanning calorimetry (DSC), differential thermal analysis (DTA) and thermogravimetric analysis (TGA), are the common tools in the study of polyacrylonitrile degradation [11][12][13][14].Semiconductor photocatalysis has been gathering much attention recently due to its promising application in chemical conversion and storage of solar energy for solar cells, hydrogen production, refractory pollutants elimination and self-cleaning surface [15][16][17][18].Among various oxide semiconductor photocatalysts, titanium oxide (TiO 2 ) has been proven so far to be the most promising material used for both fundamental research and practical applications. Because of its highly efficient photoreactivity, biological and chemical inertness, cost effectiveness, non-toxicity, and long-term stability against photocorrosion and chemical corrosion, titanium dioxide has been frequently employed in the environmental treatment and purification purposes [18][19][20][21][22]. Anatase TiO 2 has been identified as the most effective and useful photocatalyst under near UV illumination [23].The pairs of free electrons and holes are formed in the conduction and va...

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“…[21][22][23][24] In this work, a bifunctional comonomer 2-methylenesuccinamic acid (MLA) with carboxyl group and amide group was synthesized to prepare poly(acrylonitrileco-2-methylenesuccinamic acid) [P(AN-co-MLA)]. Compared with IA, the amide group of the MLA replaces one of the carboxyl groups, which can reduce the probability of chain termination during polymerization process and improve molecular weight of PAN polymer effectively.…”

Section: 21mentioning

confidence: 99%

Poly(acrylonitrile-co-2-methylenesuccinamic acid) as a potential carbon fiber precursor: preparation and stabilization

et al. 2017

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A novel bifunctional comonomer 2-methylenesuccinamic acid (MLA) was synthesized to prepare poly(acrylonitrile-co-2-methylenesuccinamic acid) [P(AN-co-MLA)] copolymers, which can improve the stabilization of polyacrylonitrile significantly as a carbon fiber precursor. The structure and stabilization of P(AN-co-MLA) copolymers with different monomer feed ratios of AN/MLA were characterized by elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Reactivity ratio studies shows that MLA possesses higher reactivity than AN, resulting in higher MLA content in P(AN-co-MLA) copolymers than in the feed. The molecular weight and conversion of copolymer decrease gradually with the increase of MLA content in the feed. Comparing with PAN homopolymer, P(AN-co-MLA) copolymer has two or even three exothermic peaks, and the initial temperature of P(AN-co-MLA) copolymer is ca. 70 C lower than that of PAN, which broadens the exothermic peak. The DH/DT reduces from 34.01 J g À1 C À1 to less than 17.67 J g À1 C À1, confirming that the incorporation of MLA can avoid centralized heat release effectively.In addition, the extent of stabilization increases as the MLA content in P(AN-co-MLA) copolymer increases under the same heat treatment conditions. The activation energy (E a ) calculation shows cyclization E a of P(AN-co-MLA) reduces from ca. 168 kJ mol À1 to ca. 110 kJ mol À1, it is concluded that synthesized comonomer MLA can significantly improve stabilization of PAN, which is conducive to the preparation of high performance carbon fiber.

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Thermal behaviour of acrylonitrile copolymers having methacrylic and itaconic acid comonomers

Cited by 193 publications

References 25 publications

Structural Evolution of Polyacrylonitrile Fibers in Stabilization and Carbonization

Structural Evolution of Polyacrylonitrile Fibers in Stabilization and Carbonization

Photoactive Polyacrylonitrile Fibers Coated by Nano-Sized Titanium Dioxide: Synthesis, Characterization, Thermal Investigation

Poly(acrylonitrile-co-2-methylenesuccinamic acid) as a potential carbon fiber precursor: preparation and stabilization

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