Structure evolution mechanism of poly(acrylonitrile/itaconic acid/acrylamide) during thermal oxidative stabilization process

Zeng, Z. T.; Shao, Ze-chun; Xiao, Ru; Lu, Youming

doi:10.1007/s10118-017-1945-2

Cited by 25 publications

(15 citation statements)

References 41 publications

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“…Figure 10 shows the morphologies of nanofibers after carbonization treatment. It is known that the TOS process causes the cyclization of nitrile groups and forms the thermally stable ladder-like structure which avoids fusing during the carbonization process [45,46]. The diameters of cPAN, cP(AN-co-IA), and cP(AN-co-AMPS) nanofibers were 222 ± 0.051 nm, 143 ± 0.049 nm, and 416 ± 0.110 nm, respectively.…”

Section: Resultsmentioning

confidence: 99%

Preparation, Stabilization and Carbonization of a Novel Polyacrylonitrile-Based Carbon Fiber Precursor

et al. 2019

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The quality of polyacrylonitrile (PAN) precursor has a great influence on the properties of the resultant carbon fibers. In this paper, a novel comonomer containing the sulfonic group, 2-acrtlamido-2-methylpropane acid (AMPS), was introduced to prepare P(AN-co-AMPS) copolymers using itaconic acid (IA) as the control. The nanofibers of PAN, P(AN-co-IA), and P(AN-co-AMPS) were prepared using the electrospinning method. The effect of AMPS comonomer on the carbon nanofibers was studied using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Raman spectrum. The structural evolutions of PAN-based nanofibers were quantitatively tracked by FTIR and XRD during the thermal oxidative stabilization (TOS) process. The results suggested that P(AN-co-AMPS) nanofibers had the lower heat release rate (ΔH/ΔT = 26.9 J g−1 °C−1), the less activation energy of cyclization (Ea1 = 26.6 kcal/mol and Ea2 = 27.5 kcal/mol), and the higher extent of stabilization (Es and SI) during TOS process, which demonstrated that the AMPS comonomer improved the efficiency of the TOS process. The P(AN-co-AMPS) nanofibers had the better thermal stable structures. Moreover, the carbon nanofibers derived from P(AN-co-AMPS) precursor nanofibers had the better graphite-like structures (XG = 46.889). Therefore, the AMPS is a promising candidate comonomer to produce high performance carbon fibers.

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Section: Resultsmentioning

confidence: 99%

Preparation, Stabilization and Carbonization of a Novel Polyacrylonitrile-Based Carbon Fiber Precursor

et al. 2019

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“…The peak located at 2244 cm –1 is the characteristic peak of PAN, which belongs to C≡N groups. 28,29 Because of the small amount of AL, only two distinct new peaks appear at 1514 and 1597 cm –1 for PAN/AL composite films, which were ascribed to the skeletal vibration of the aromatic rings of AL. 30,31 As the AL blend ratio increases, the IR peaks at 1514 and 1597 cm –1 become stronger, which indicate more AL in the composite film.…”

Section: Resultsmentioning

confidence: 99%

Incorporation of Alkali Lignin in Polyacrylonitrile: Phase Separation, Coagulation, and Cyclization Kinetics

Zhou

Hao

et al. 2019

ACS Omega

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In this study, we systematically investigated the phase separation behaviors of polyacrylonitrile (PAN)/alkali lignin (AL)/dimethyl sulfoxide (DMSO) systems and found that the addition of AL causes phase separation and the systems form sea (PAN)/island (AL) types of structures. Interestingly, the AL-rich domains are very stable even after a long time of storage up to 15 days. Additionally, how the phase separation affected the solution rheology, the coagulation process and PAN cyclization were explored. The addition of AL in PAN/DMSO solutions changes the solution viscosity and gelation behaviors. Also, the existence of AL-rich domains accelerates the coagulation rate of the PAN solution in water. Because AL degrades at a lower temperature than PAN, it reduces the PAN cyclization temperature but leads to a higher cyclization activation energy, which could be caused by their different initiation mechanisms. These results would be useful to understand how the addition of AL affects the PAN solution structures, solution rheology, solution coagulation behaviors, and PAN stabilization reactions.

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“…The incorporation of IA monomer into the PAN matrix initiated the cyclization reaction at a relatively low temperature through an ionic mechanism and relaxed the heat release [26][27][28]. Thus, many researchers studied the effects of IA on the thermal stabilization of PAN copolymers, which showed that the introduction of IA comonomer promoted cyclization reactions and broadened the range of exothermic temperature, and PAN-IA copolymers had lower activation energy of cyclization reaction during this processing [29][30][31][32][33][34][35]. Because the thermal stabilization depends on the nature and the content of comonomer as well as the polymerization methods of PAN-IA copolymers [9,11,19,30,32,[35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Thermal Analysis and Crystal Structure of Poly(Acrylonitrile-Co-Itaconic Acid) Copolymers Synthesized in Water

et al. 2020

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The composition and structure of polyacrylonitrile (PAN) precursors play an important role during thermal stabilization, which influences the properties of the resulting carbon fibers. In this paper, PAN homopolymer and PAN-itaconic (IA) copolymers with different IA contents were synthesized by aqueous phase precipitation polymerization. The effects of IA content on the structure and thermal properties were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The morphology of PAN polymers showed that the average size of the PAN particles increased with the increase of IA content in the feed. The content of the IA comonomer on the copolymers was quantitatively characterized by the relative absorbance intensity (A1735/A2243) in FTIR spectrum. With the increase of IA content in the feed, PAN-IA copolymers exhibited lower degree of crystallinity and crystal size than the control PAN homopolymer. The results from DSC curves indicated that PAN-IA1.0 copolymers had lower initial exothermic temperature (192.4 °C) and velocity of evolving heat (6.33 J g−1 °C−1) in comparison with PAN homopolymer (Ti = 238.1 °C and ΔH/ΔT = 34.6 J g−1 °C−1) in an air atmosphere. TGA results suggested that PAN-IA1.0 copolymers had higher thermal stability than PAN homopolymer, which can form a ladder structure easier during thermal processing. Therefore, PAN-IA1.0 copolymers would be a suitable candidate for preparing high performance PAN based carbon fibers.

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Structure evolution mechanism of poly(acrylonitrile/itaconic acid/acrylamide) during thermal oxidative stabilization process

Cited by 25 publications

References 41 publications

Preparation, Stabilization and Carbonization of a Novel Polyacrylonitrile-Based Carbon Fiber Precursor

Preparation, Stabilization and Carbonization of a Novel Polyacrylonitrile-Based Carbon Fiber Precursor

Incorporation of Alkali Lignin in Polyacrylonitrile: Phase Separation, Coagulation, and Cyclization Kinetics

Thermal Analysis and Crystal Structure of Poly(Acrylonitrile-Co-Itaconic Acid) Copolymers Synthesized in Water

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