A Novel Carbon Nanofiber Precursor: Poly(acrylonitrile-co-vinylacetate-co-itaconic acid) Terpolymer

Can, Dilek Suadiye; Baskan, Havva; Gümrükçü, Selin; Saraç, A. Sezai̊

doi:10.1166/jnn.2019.16309

Cited by 6 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Te tendency of Mw, which decreases with increasing x 2 , is due to an increase in the number of active centers in the growing polymer chains, which allows the chain to be closed more easily. Tis is supported by the fndings of Can et al [19,20], where they also obtained a reduction in molecular weight with the increasing comonomer amount in the polymer formed.…”

Section: Comparison Between Model Predictions and Experimentalmentioning

confidence: 75%

Analytical Steady-State Model for the Free Radical Solution Copolymerization of Acrylonitrile and Vinyl Acetate and Their Charge-Transfer Complex in a Continuous Stirred Tank Reactor

Meza-Díaz,

Tapia-Picazo,

Bonilla-Petriciolet

et al. 2023

International Journal of Chemical Engineering

View full text Add to dashboard Cite

In this study, a mathematical model of the copolymerization of AN-VA in a continuous stirred tank reactor (CSTR) was developed considering charge-transfer complexes (CTCs). CTC formation between acrylonitrile (AN) and vinyl acetate (VA) was demonstrated using UV-VIS spectrophotometry and molecular orbital theory. The rate constants and equilibrium constants of the complexes were calculated from a model of the simultaneous participation of complexes and free monomers and the molar ratio method. Furthermore, the participation of CTCs in propagation was included because of their high reactivity. All the simultaneous equations defined to analyze the reactor parameters were analytically solved, and the results of the model were in terms of operative variables such as monomer conversion, average molecular weight, and the mole fraction of monomer 2 (i.e., VA) in the polymer formed. The results of the predictions of the developed model were compared with the experimental data for validation. This prediction was also compared with the reactor model solution without considering the CTC, which showed deviations that were more significant than those of the CTC model. These results represent a quantitative way to analyze the order of magnitude of the impact of the formation of the complexes in the analyzed polymerization system.

show abstract

Section: Comparison Between Model Predictions and Experimentalmentioning

confidence: 75%

Analytical Steady-State Model for the Free Radical Solution Copolymerization of Acrylonitrile and Vinyl Acetate and Their Charge-Transfer Complex in a Continuous Stirred Tank Reactor

Meza-Díaz,

Tapia-Picazo,

Bonilla-Petriciolet

et al. 2023

International Journal of Chemical Engineering

View full text Add to dashboard Cite

show abstract

“…In general, the uniform sequence structure of the PAN precursor is key to produce high-performance carbon fibers, and the polymerization process is particularly important . PAN copolymers contain a small amount of comonomers, e.g., methyl acrylate (MA), methyl methacrylate (MMA), itaconic acid (IA), and acrylic acid (AA), to overcome the disadvantages of the PAN homopolymer, such as the low processability and high exothermic heat generation during thermal oxidative stabilization (TOS). , Among these comonomers, acidic comonomers contain carboxyl groups, which can change the free radical mechanism to the ionic mechanism of the cyclization reaction during TOS . According to the existing research, IA is the most efficient acidic comonomer for the two corresponding carboxylic groups .…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, to obtain high-quality PAN precursors, it is necessary to ensure the regulation of the IA comonomer in the PAN copolymer with a suitable content and uniform sequence distribution during the polymerization process. However, the sequence distribution of the IA in the PAN copolymer is always inhomogeneous owing to the traditional free radical polymerization, which can be attributed to the different reactivity ratios of AN and IA. , Some researchers ,, highlighted that the reactivity ratios r 1 (AN) and r 2 (IA) are always less than and greater than 1, respectively, which indicates that both the growing radicals ∼∼∼AN· and ∼∼∼IA· exhibit a higher preference for the IA comonomer unit than that for the AN monomer unit, resulting in an inhomogeneous sequence distribution.…”

Section: Introductionmentioning

confidence: 99%

Macromolecular Chain Structure Regulation of AN–MA–IA Aqueous Copolymerization with a Water-Soluble Azo Initiator AIBA

Tong

Pan

et al. 2021

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The performance of acrylonitrile (AN)–methyl acrylate (MA)–itaconic acid (IA) terpolymer is closely related to the uniformity of the sequence structure. In this work, the changes in the dissociative behavior and reactivity of the IA with acidity were examined through calculations based on the density functional theory (DFT). The results of the energy barrier, kinetics, SOMO–LUMO energy gap, and electrostatic repulsion of different dissociated forms demonstrated that the corresponding reactivity between the IA with the AN propagation radical follows the order IA > IA– > IA2–, although the IA– and AN exhibit a similar reactivity. Furthermore, the relationship between the reactivity and dissociated state of the IA monomer was clarified considering the results of the reactivity ratios. A strategy of controlling the sequence structure of polyacrylonitrile (PAN) terpolymers at a stable pH control with the IA‑ dissociated state was established. Notably, a water-soluble azo initiator, 2,2′-azobis (2-methylpropionamidine) dihydrochloride (AIBA), was adopted because its initiation process is not related to the pH. AIBA was applied in the aqueous polymerization process to obtain a PAN terpolymer with a relatively uniform chain distribution. The results demonstrated that when the pH value is controlled at 4.7, most of the IA exists in the first-step dissociated form, and its reactivity is comparable to that of monomer AN. In addition, the composition of terpolymer is as follows: 94.96–95.07% of AN, 3.11–3.36% of MA, and 1.68–1.82% of IA, with the raw material ratios being 95:3.2:1.8, indicating the presence of a PAN terpolymer with a uniform chain distribution.

show abstract

“…There are numerous literatures reporting the pre-treatment of the PAN fibers before pre-oxidation but most of the chemicals used are directly utilized to prepare carbon fibers. [24][25][26][27][28] To the best of our knowledge, the effects of chemical pre-treatment on structure and property of PAN-based preoxidized fibers have not been reported. Therefore, in this study, a simple and convenient impregnation method was proposed to treat the pristine PAN fibers; in other words the OPF were made from the pristine PAN fibers through pre-treated with HA hydrochloride and monoethanolamine (MEA) alone or jointly followed by pre-oxidation in air.…”

Section: Introductionmentioning

confidence: 99%

Effects of chemical pre-treatment on structure and property of polyacrylonitrile based pre-oxidized fibers

Sun

Song

Zhang

et al. 2020

Journal of Engineered Fibers and Fabrics

View full text Add to dashboard Cite

Polyacrylonitrile-based pre-oxidized fibers with improved thermal stability, flame retardant, and mechanical properties were made from the pristine polyacrylonitrile fibers through chemical pretreatment followed by pre-oxidation in air. The morphological structure of the polyacrylonitrile-based pre-oxidized fibers was investigated by Fourier transfer infrared spectra, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectrometer. The changes of characteristic functional groups and chemical compositions confirmed the successful modification of the polyacrylonitrile fibers during pre-treatment. The grooves and cracks on the surface of polyacrylonitrile-based pre-oxidized fibers were remarkably decreased in comparison with that of pristine polyacrylonitrile fibers. The evolution of crystalline structure of the polyacrylonitrile fibers proved the occurrence of cyclization reactions during pre-oxidation. Meanwhile, thermal stability, flame retardant, and mechanical properties of polyacrylonitrile-based pre-oxidized fibers were also investigated by thermogravimetric analyzer, oxygen index meter, micro combustion calorimeter, and single fiber tensile tester, respectively. The results demonstrated that the polyacrylonitrile-based pre-oxidized fibers initially pre-treated by hydroxylamine hydrochloride, followed by monoethanolamine, had a high limiting oxygen index of 40.1 and breaking strength of 2.03 cN/dtex. The peak of heat release rate and total heat release of polyacrylonitrile-based pre-oxidized fibers decreased significantly while its charred residues increased, contributing to the improved flame retardant property.

show abstract

A Novel Carbon Nanofiber Precursor: Poly(acrylonitrile-co-vinylacetate-co-itaconic acid) Terpolymer

Cited by 6 publications

References 0 publications

Analytical Steady-State Model for the Free Radical Solution Copolymerization of Acrylonitrile and Vinyl Acetate and Their Charge-Transfer Complex in a Continuous Stirred Tank Reactor

Analytical Steady-State Model for the Free Radical Solution Copolymerization of Acrylonitrile and Vinyl Acetate and Their Charge-Transfer Complex in a Continuous Stirred Tank Reactor

Macromolecular Chain Structure Regulation of AN–MA–IA Aqueous Copolymerization with a Water-Soluble Azo Initiator AIBA

Effects of chemical pre-treatment on structure and property of polyacrylonitrile based pre-oxidized fibers

Contact Info

Product

Resources

About