Synthesis and characterization of acrylonitrile methyl acrylate statistical copolymers as melt processable carbon fiber precursors

Bhanu, V. A.; Rangarajan, Pratima; Wiles, Kenton B.; Bortner, Michael J.; Sankarpandian, M; Godshall, D.; Glass, Thomas E.; Banthia, A. K.; Yang, Jinn‐Shyong; Wilkes, Garth L.; Baird, Donald G.; McGrath, James E.

doi:10.1016/s0032-3861(02)00330-0

Cited by 112 publications

(100 citation statements)

References 16 publications

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“…The experimental conditions and characteristics of the synthesized polymers are summarized in Table 1. It was noteworthy that the PAN copolymers containing CA synthesized in this study showed higher M v than those synthesized in earlier reports using other comonomers such as methyl acrylate (MA) and IA [11,12], suggesting that the presence of CA comonomer accelerated the growth of polymer chains, leading to higher molecular weight. So far, the large diameter of the polymer fibers has been one of the limitations of carbon fiber strength.…”

Section: Resultscontrasting

confidence: 44%

Effects of comonomer with carboxylic group on stabilization of high molecular weight polyacrylonitrile nanofibrous copolymers

Lei¹,

Devarayan²,

Li³

et al. 2014

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New precursors, poly(acrylonitrile-co-crotonic acid) (poly(AN-CA)) and poly(acrylonitrileco-itaconic acid-co-crotonic acid) (poly(AN-IA-CA)) copolymers, for the preparation of carbon fibers, were explored in this study. The effects of comonomers with acidic groups, such as crotonic acid (CA) and/or itaconic acid (IA), on the stabilization of nanofibrous polyacrylonitrile (PAN) copolymers were studied. The extent of stabilization, evaluated by Fourier transform infrared spectroscopy, revealed that the CA comonomer could retard/control the stabilization rate of PAN, in contrast to the IA comonomer, which accelerated the stabilization process. Moreover, the synthesized PAN copolymers containing CA possessed higher Mv than those of the IA copolymers and also showed outstanding dimension stability of nanofibers during the stabilization, which may be a useful property for improving the dimensional stability of polymer composites during manufacturing.

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Section: Resultscontrasting

confidence: 44%

Effects of comonomer with carboxylic group on stabilization of high molecular weight polyacrylonitrile nanofibrous copolymers

Lei¹,

Devarayan²,

Li³

et al. 2014

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“…According to Masson [2] the polydispersity of the acrylic polymers is a function of the method of polymerization and typical values for free-radical polymerization (redox system) range from 2 to 3, though some commercial processes can yield higher polydispersity index values. Table 2 shows that a higher polydispersivity was achieved in relation to other works reported in the literature [2,18] . During PAN AN/VDC synthesis a higher concentration of initiators can possibly create an excess of free radicals.…”

Section: Molecular Weight By Gpcsupporting

confidence: 54%

“…The reaction is undertaken in a carefully controlled acid environment, because the bisulfite ion and the Fe 3+ ion formed by oxidation are soluble [4] . Several works reported the used reaction temperature at 60°C for polyacrylonitrile copolymer polymerization [18][19][20] . After overflowing the suspension, an aqueous slurry of polymer particles is obtained and mixed with tetrasodium ethylene diamine tetraacetic acid (EDTA) to stop redox radical initiation and stop the polymerization [2] .…”

Section: Suspension Polymerization-redox Systemmentioning

confidence: 99%

“…Unreacted monomers, through a countercurrent flow of steam from the bottom of the column (5), are condensed (6) to reuse in the polymerization process. The aqueous suspension is collected in a reservoir and transferred for later steps (washing, filtration and drying) [2,[15][16][17][18][19] . Table 1.…”

Section: Suspension Polymerization-redox Systemmentioning

confidence: 99%

“…In the case PAN fibers, raw materials (monomers, co-monomers and catalyst) and synthesis conditions (temperature, residence time, pH and catalyst concentration) have a strong impact on polymer molecular weight. In fact, molecular weight defines final mechanical properties after fiber processing, related to spinning and draw ratio [18,26] . Qin [26] , for instance, reported for a PAN fiber obtained by the synthesis between acrylonitrile, methyl acrylate and itaconic acid, a tensile strength of 348 MPa and 381 MPa, and a Young´s Modulus of ~2.5 GPa, using a stress ratio of 5.0, related to a molecular weight (M n ) of 97,000 and 169,000 , respectively.…”

Section: Molecular Weight By Gpcmentioning

confidence: 99%

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Synthesis and Thermal Behavior of Polyacrylonitrile/Vinylidene Chloride Copolymer

et al. 2014

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Polyacrylonitrile fiber encompasses a broad range of products based on acrylonitrile (AN) which is readily copolymerized with a wide range of ethylenic unsaturated monomers giving rise to polymers with different characteristics and applications. Such products can be designed for cost-effective, flame and heat resistant solutions for the textile industry, aircraft and automotive markets. In the present work acrylonitrile was copolymerized with vinylidene chloride (VDC) by conventional suspension polymerization process via redox system, with an initial content of 10%/mass of the VDC monomer. The copolymer average molecular weight was obtained by Gel Permeation Chromatography (GPC) and by intrinsic viscosity analysis. To control the polymerization process continuously, qualitative and quantitative analysis of the chloride content in the PAN AN/VDC copolymer structure was accomplished by using X-ray fluorescence and potentiometric titration techniques. A good correlation was found between these two techniques, leading to a straightforward verification of VDC in the polymer structure. The thermal behavior of PAN AN/VDC copolymer was performed by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The results showed that VDC monomers exhibited a nearly stoichiometric reaction with acrylonitrile, copolymerizing about 90% of its initial mass. VDC changed significantly the polyacrylonitrile thermal behavior, decreasing the polymer degradation temperature by about 40-50°C.

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Switchable Polyacrylonitrile‐Copolymer for Melt‐Processing and Thermal Carbonization—3D Printing of Carbon Supercapacitor Electrodes with High Capacitance

2022

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allowing fast charge-discharge kinetics, long cycling stability, and high capacitance. [1][2][3][4] Typically, such carbon electrodes are produced from active carbon powders. [5] The required structural integrity of the electrode can only be achieved by mixing the active carbon powder with binders; however, these binders are often electrochemically inert and decrease the overall performance of the electrodes by blocking the surface and porosity of the active material. To produce electrodes without binder, carbon fiber non-wovens present ideal materials for components in fuel cells, batteries, and supercapacitors. [5][6][7][8][9][10][11] The most widely used precursor for carbon fibers and materials is polyacrylonitrile (PAN). [12] PAN can be converted into carbon materials in a two-step thermal conversion process. The first step is called stabilization, in which the nitrile groups engage in mostly intramolecular cyclization reactions, forming polymer ribbons. Stabilization is conducted in an oxidative atmosphere between 200 and 300 °C. [13][14][15] Strong dipolar interactions between the nitrile groups entail a high melting temperature T m , well above the activation energy for the cyclization reaction-or stabilization. The second step is the carbonization, in which the polymer ribbons fuse to graphitic domains. Carbonization is conducted in an inert atmosphere above 1000 °C. [13,16,17] Because of its sensitivity towards high temperatures-with potential for thermal run-away, due to the exothermic nature of the stabilization reaction-PAN is typically processed from solution.However, solution processing limits the final architectures of the desired carbon materials to fibers and films. [18][19][20] Fiber spinning and film formation processes are energy consuming and costly, as they require large amounts of solvents, which on an industrial scale have to be recovered and eventually disposed of. [21][22][23][24] A much more economic manufacturing approach would be to process PAN from its melt. [17,25,26] This strategy would enable 3D printing techniques such as polymer extrusion-based additive manufacturing (EAM) with full freedom-ofdesign, expanding the possible shapes of carbon materials from 1D fibers and 2D films to monolithic 3D workpieces. To our advantage, EAM would allow fully automated shaping of PAN into complex structures. EAM is scalable, fast, solvent-free, and Polyacrylonitrile (PAN) represents the most widely used precursor for carbon fibers and carbon materials. Carbon materials stand out with their high mechanical performance, but they also show excellent electrical conductivity and high surface area. These properties render carbon materials suitable as electrode material for fuel cells, batteries, and supercapacitors. However, PAN has to be processed from solution before being thermally converted to carbon, limiting its final format to fibers, films, and non-wovens. Here, a PAN-copolymer with an intrinsic plasticizer is presented to reduce the melting temperature and avoid undesired entering of the t...

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Synthesis and characterization of acrylonitrile methyl acrylate statistical copolymers as melt processable carbon fiber precursors

Cited by 112 publications

References 16 publications

Effects of comonomer with carboxylic group on stabilization of high molecular weight polyacrylonitrile nanofibrous copolymers

Effects of comonomer with carboxylic group on stabilization of high molecular weight polyacrylonitrile nanofibrous copolymers

Synthesis and Thermal Behavior of Polyacrylonitrile/Vinylidene Chloride Copolymer

Switchable Polyacrylonitrile‐Copolymer for Melt‐Processing and Thermal Carbonization—3D Printing of Carbon Supercapacitor Electrodes with High Capacitance

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