Free Radical Polymerization Of Acrylonitrile Research Articles

Constructing the Polymer Molecules to Regulate the Electrode/Electrolyte Interface to Enhance Lithium-Metal Battery Performance.

Lithium-ion batteries, with high energy density and long cycle life, have become the battery of choice for most vehicles and portable electronic devices; however, energy density, safety and cycle life require further improvements. Single-functional group electrolyte additives are very limited in practical applications, a ternary polymer bifunctional electrolyte additive copolymer (acrylonitrile-butyl hexafluoro methacrylate- poly (ethylene glycol) methacrylate- methyl ether) (PMANHF) was synthesized by free radical polymerization of acrylonitrile, 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate and poly (ethylene glycol) methyl ether methacrylate. A series of characterizations show that in Li metal anodes, the preferential reduction of PMANHF is conducive to the formation of a uniform and stable solid electrolyte interphase layer, and Li deposition is uniform and dense. At the NCM811 cathode, a film composed of LiF- and Li3N-rich is formed at the cathode-electrolyte interface, mitigating the side reaction at the interface. At 1.0 mA cm-2, the Li/Li cell can be stabilized for 1000 cycles. In addition, the Li/NCM811 cell can stabilize 200 cycles with a cathode capacity of 153.7 mAh g-1, with the capacity retention of 89.93 %, at a negative/positive capacity ratio of 2.5. This study brings to light essential ideas for the fabrication of additives for lithium-metal batteries.

Analysis of Sorption and Permeation of Acetonitrile–Water Mixtures through Nanoclay-Filled Copolymer Membranes

Several hydrophilic membranes were prepared by solvent casting from filled copolymers. These filled copolymers were synthesized by free radical polymerization of acrylonitrile (AN) and N-vinylpyrrolidone (NVP) monomers in different comonomer ratios (AN/NVP) in the presence of a nanosized clay. The membrane polymers were analyzed by NMR, Fourier transform infrared spectroscopy, X-ray diffraction, differential thermal and thermogravimetric analyses, scanning electron microscopy, mechanical properties, and dynamic mechanical analysis for characterization of its structural configuration, functionalities, copolymer composition, distribution of clay in the copolymer, and the strength and stability of the membrane under dynamic and thermal stress. The sorption and pervaporation of acetonitrile–water mixtures through these membranes were studied at varied copolymer compositions, mass % of clay, feed concentrations of water, and feed temperatures. Sorption data were analyzed by binary and ternary solvent/membrane ...

Synergetic effect of multi-site phase transfer catalysis system mediated free radical polymerization of acrylonitrile – a kinetic study

In this work, the kinetics and mechanism of free radical polymerization of acrylonitrile (AN) using potassium peroxydisulphate (PDS-K2S2O8) as a water soluble initiator in the presence of synthesized 4,4'-dihexadecyl-1,1'-bipyridine diiumdichloride (DHBPDDC) as multi-site phase-transfer catalyst (MPTC) has been investigated. The polymerization reaction were carried out under nitrogen atmosphere and unstirred condition at constant temperature 60+1°C in ethyl acetate/water biphasic medium. The effects of variation of monomer(AN), initiator(PDS) and catalyst(MPTC) solvent polarity and temperature on the rate of polymerisation (Rp) were ascertained. The order with respect to monomer(acrylonitrile) was found to be unity. The order with respect to initiator and catalyst was found to be 0.51, 0.48 respectively. However, an increase in the polarity of the solvent has slightly increased the rate of polymerization value (Rp). Based on the results obtained, a suitable kinetic mechanism scheme has been proposed to account for the experimental observations and its significance was discussed. The other thermodynamic parameters such as entropy of activation ((∆S#), enthalpy of activation (∆H#) and free energy of activation (∆G#) have been calculated.

Effect of ultrasound in the free radical polymerization of acrylonitrile under a new multi-site phase-transfer catalyst – A kinetic study

The kinetics of polymerization of acrylonitrile (AN) was carried out under heterogeneous condition using a new multi-site phase-transfer catalyst (MPTC), viz., N,N′-dihexyl-4,4′-bipyridinium dibromide in the presence of water soluble initiator, potassium peroxydisulphate (PDS) under chlorobenzene/water two phase system assisted by ultrasound irradiation at constant temperature 60+1°C under nitrogen atmosphere. The rate of polymerization increases with an increasing the concentrations of AN, MPTC and PDS. The order with respect to [AN], [MPTC], and [PDS] were found to be 1.01, 1.03 and 0.52, respectively. Based on the observed results a suitable mechanism has been proposed to account for the experimental observations followed by a discussion on its significance.

Optimization of amine-terminated polyacrylonitrile synthesis and characterization

Amine-terminated PANs were prepared in two steps. The first step includes free radical polymerization of acrylonitrile (AN) using initiator pair of ammonium persulfate and sodium thiosulfate as redox system. In the second step, the amino groups were introduced through the reaction of polyacrylonitrile with excess of different diamines (10-fold) including ethylenediamine (EDA), hexamethylenediamine (HMDA) and octamethylenediamine (OMDA), to yield PAN–EDA, PAN–HMDA and PAN–OMDA, respectively. Optimization of the amine-terminated PANs synthesis was carried out at different temperatures (30–90°C) and different time intervals (4–24h). In addition, the introduction of the amino group was followed by the piperidine test and recording of the FT-IR spectra. All polymers were characterized by, 1H NMR spectra, thermogravimetric analysis (TGA), and FT-IR spectra.

Synthesis of polyacrylonitrile via ARGET ATRP using CCl4 as initiator

AbstractActivators regenerated by electron transfer (ARGET) for atom transfer radical polymerization (ATRP) of acrylonitrile (AN) was investigated using carbon tetrachloride (CCl4) as initiator, ferric trichloride anhydracs (FeCl3)/iminodiacetic acid (IDA) as catalyst system, L‐ascorbic acid (VC) as reducing agent, and N,N‐dimethylformamide (DMF) as solvent. Kinetic data of polymerization demonstrated the features of living/controlled free‐radical polymerization. The conversion of AN increased with the increasing concentration of CCl4, [FeCl3]/[IDA] catalyst system and VC. The molecular weight decreased with the increasing concentration of CCl4, [FeCl3]/[IDA] catalyst system and VC. The value of polydispersity index (PDI) increased with the increasing concentration of [FeCl3]/[IDA] catalyst system and VC, while the value of PDI decreased first and then increased with the increasing concentration of CCl4 and IDA. 1H‐NMR spectra of PAN further verified the features of living/controlled free radical polymerization of AN. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Relevance of backbiting and beta‐scission reactions in the free radical polymerization of Acrylonitrile

AbstractSummary: In this work, backbiting and beta‐scission reactions are investigated through Quantum Chemistry methods by adopting the Becke 3 parameters and Lee Yang Parr functional (B3LYP) and 6‐31G(d,p) basis set. Namely, the 1:3, 1:5 and 1:7 backbiting reactions are studied for acrylonitrile polymerization. It was found that the backbiting 1:5 is the most favorited because this kinetic event leads to the formation of a 6 membered transition state, while the backbiting 1:3 requires high activation energy due to the formation of a highly strained 4 membered ring. 7:3 backbiting reaction was also examined, since it is an alternative pathway that can explain the formation of defects generated by radicals in the third position. Simulations showed that this kinetic step is characterized by high rate constant because of its low activation energy.The right and left beta‐scission reactions from the mid chain radicals formed by the considered backbiting reactions are also studied. Computational analysis demonstrated that all beta‐scission reactions are endothermic and both the right and left beta‐scission reactions have the same activation energy, which seems to be more influenced by the position of the mid chain radical.

Phase Transfer Catalyst-Induced Free Radical Polymerization of Acrylonitrile Using Water Soluble Initiator – A Kinetic Study

In this paper, we report the kinetics and mechanism of phase transfer catalyzed radical polymerization of acrylonitrile (AN) using potassium peroxydisulphate as water-soluble initiator. The polymerization was executed unstirred at 60°C under nitrogen atmosphere. The roles of concentration of monomer, initiator, catalyst, temperature and effect of solvent polarity were evaluated. Based on the results obtained, a viable kinetic scheme and mechanism have been proposed.

Free Radical Polymerization of Acrylonitrile Using Potassium Peroxy Disulphate Initiator and a Phase Transfer Catalyst

Free radical polymerization of acrylonitrile with the di-site phase transfer catalyst 1,4-bis(tetramethylhexyl)ethylenediammonium bromide (TMHEDAB) was investigated using the water-soluble initiator PDS (potassium peroxydisulphate) and water-insoluble solvent ethylacetate in an aqueous-organic biphase system at 60±1°C under nitrogen atmosphere at fixed pH and ionic strength. Rp increased with the increase in concentration of the monomer, initiator and catalyst. The order of Rp, with respect to monomer and catalyst concentration was found to be unity and with respect to initiator was found to be 0.5. A suitable mechanism has been proposed and its significance was discussed. The polymers obtained were characterized by spectral studies such as FTIR, 1H-NMR, XRD, DSC, and TGA.

The study of free radical polymerization of acrylonitrile by oxidation–reduction system using potassium persulfate–thiourea in aqueous medium

AbstractThe polymerization kinetics of acrylonitrile (AN) with the potassium persulfate (K2S2O8)/thiourea redox system has been investigated volumetrically in an aqueous medium in the temperature range of 40–80°C. The rate of polymerization (Rp) and rate of K2S2O8 disappearance have been measured. The effects of some water‐miscible organic solvents, cationic, anionic, nonionic surfactants, and complexing agents on the Rp were investigated. The temperature dependence of the rate was studied, and the activation parameters were computed using the Arrhenius and Eyring plots. The effects of organic solvents on polymerization were also investigated. All of them depressed both the initial rate and limiting conversion. A mechanism consistent with the experimental data involving K2S2O8–thiourea complex formation, which generates free radicals, is suggested. Molecular weight of the polymer was determined by viscometry. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Polymerization of acrylonitrile using potassium peroxydisulfate as an initiator in the presence of a multisite phase-transfer catalyst: A kinetic study

In this article, the kinetics and mechanism of the free-radical polymerization of acrylonitrile (AN) using potassium peroxydisulfate (PDS) as a water-soluble initiator in the presence of synthesized 1,4-bis(triethyl methyl ammonium) benzene dichloride (DC-X) as a phase-transfer catalyst (PTC) were studied. The polymerization reactions were carried out under inert and unstirred conditions at a constant temperature of 60 ± 1°C in cyclohexane/water biphasic media. The rate of polymerization (Rp) increased with an increase in the concentrations of AN, PTC, and PDS. The order with respect to the monomer, initiator, and PTC was found to be 1.0, 0.5, and 0.5, respectively. Rp was independent of the ionic strength and pH of the medium. However, an increase in the polarity of the solvent slightly increased the Rp value. On the basis of the obtained results, a mechanism is proposed for the polymerization reaction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Kinetic studies on free radical polymerization of acrylonitrile, initiated by chloramine-T/hydrogen peroxide redox system

The Kinetics of polymerization of Acrylonitrile initiated by chloramine-T/H2O2 Redox System was studied in aqueous medium in the temperature range of 35–50°C. The effects of variations such as [Monomer], [CAT], [H2O2], temperature, and chloramine-T disappearance (−Rm) were measured. The effect of some water- miscible organic solvents and surfactants on the rate of polymerization was investigated. The polymerization process is initiated by the free radical arising from oxidation of H2O2 by chloramine-T and terminated by the mutual combination of the growing polymer radicals. Based on the kinetic results, a suitable reaction scheme is proposed and discussed for the various rates of polymerization and thermodynamic parameters were evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5877–5883, 2006

Free Radical Polymerization of Acrylonitrile in Green Ionic Liquids

AbstractFree radical polymerization of acrylonitrile (AN) in ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim][BF4]), 2,2;m1‐azobisisobutyronitrile (AIBN) as initiator was investigated. Early investigations on polymerizations using ionic liquids indicate that they serve as especially good solvents to achieve high molecular weight polymers. Free radical polymerizations result in higher molecular weight polymers, for ionic liquids have low chain transfer constants and act to stabilize the active radical during the process of polymerization. The thermal stability of polymers synthesized in ionic liquids have be improved obviously than that in traditional solvents.

Phase-transfer catalysis: Free-radical polymerization of acrylonitrile using potassium peroxomonosulphate- tetrabutyl phosphonium chloride catalyst system: A kinetic study

This article presents the systematic study of kinetics and mechanism of phase-transfer-catalyzed free-radical polymerization of acrylonitrile (AN) and water-soluble initiator potassium peroxomonosulphate (PMS) coupled with tetrabutyl phosphonium chloride (TBPC) in ethyl acetate/water biphase system in the temperature range 45–55°C at fixed pH and ionic strength. The rate of polymerization increases with an increase in concentrations of AN, PMS, and phase transfer catalyst, PTC. It was observed that Rp is proportional to [AN]1.5, [KHSO55−]0.5, and [TBPC]0.5. A suitable kinetic scheme has been proposed to account for the experimental observations and its significance was discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1564–1571, 2000

Free Radical Polymerization of Acrylonitrile: Mass Spectrometric Identification of the Nitroxide-Trapped Oligomers Formed in and Estimated Rate Constants for Each of the First Eight Propagation Steps

The first 10 addition products in the free radical polymerization of acrylonitrile initiated by AIBN have been trapped and identified; the resulting yields have allowed individual values of the first eight propagation rate constants to be estimated. These are the first realistic experimentally based estimates of a reasonable sequence of early propagation rate constants in any free radical polymerization. In this experiment, the concentration of the nitroxide trapping agent was maintained at a level sufficiently high to prevent the formation of high polymer, yet low enough to allow a competitive monomer addition to form the lower members of the propagation series before being trapped to form the oligomeric addition products. These oligomers were identified and quantified by electrospray ionization mass spectrometry operated in the selected ion recording mode in series with HPLC−UV. The results have allowed the first eight individual propagation rate constants, kAn (n = 1−8), to be estimated: The values of kAn at 75 °C decrease from 5.4 × 103 L mol-1 s-1 with n = 1 to a minimum of 2.1 × 103 L mol-1 s-1 with n = 3 before leveling off with a constant value of 4.8 × 103 L mol-1 s-1 at n > 5.

Crown Ether As The Phase‐Transfer Catalyst for Free Radical Polymerization of Hydrophobic Vinyl Monomers

AbstractVarious crown ethers were used as phase‐transfer catalysts for free radical polymerizations of some water‐insoluble vinyl monomers such as acrylonitrile, methylmethacrylate and styrene with persulfate as initiator. The catalytic abilities of these crown ethers for free radical polymerization of acrylonitrile with S2O82−ion as an initiator were in the order: 18‐crown‐6 > 15‐crown‐4 > 12‐crown‐4 > benzo‐15‐crown‐5 > dibenzo‐18‐crown‐6. Among various persulfates such as Na2S2O8 K2S2O8 and (NH4)2S2O8, ammonium persulfate was the optimum initiator for the polymerization of acrylonitrile catalyzed by 18‐crown‐6 or 15‐crown‐5. Among the organic solvents used, chloroform seems to be the best solvent for the catalytic polymerization of acrylonitrile. An apparent activation energy of 72.9 kJ mol−1 was observed for the polymerization of acrylonitrile. The catalytic reaction rates of free radical polymerization for these hydrophobic vinyl monomers were in the order: acrylonitrile > methylmethacrylate > styrene > isoprene. Effects of concentrations of crown ether, initiator, and nitrogen on the polymerization of these vinyl monomers were investigated.

Metal chelates in vinyl polymerization: Kinetics and mechanism of acrylonitrile polymerization initiated by Cu(II) imine complexes

AbstractThe free radical polymerization of acrylonitrile (AN) initiated by Cu(II) 4‐anilino 2‐one [Cu(II) ANIPO] Cu(II), 4‐p‐toluedeno 3‐pentene 2‐one [Cu(II) TPO], and Cu(II) 4‐p‐nitroanilino 3‐pentene 2‐one [Cu(II) NAPO] was studied in benzene at 50 and 60°C and in carbon tetrachloride (CCl4), dimethyl sulfoxide (DMSO), and methanol (MeOH) at 60°C. Although the polymerization proceeded in a heterogeneous phase, it followed the kinetics of a homogeneous process. The monomer exponents were ≥2 at two different temperatures and in different solvents. The square‐root dependence of Rp on initiator concentration and higher monomer exponents accounted for a 1:2 complex formation between the chelate and monomer. The complex formation was shown by ultraviolet (UV) study. The activation energies, kinetics, and chain transfer constants were also evaluated.

Free radical polymerization of acrylonitrile in dimethylsulphoxide solutions

The gamma-ray initiated polymerization of acrylonitrile in DMSO solutions was investigated at various monomer concentrations and temperatures. In a narrow range of monomer concentrations (70–80%), the “auto-acceleration index” of the reaction is higher than in the bulk polymerization. Some auto-acceleration persists at high DMSO contents when the reaction proceeds in a homogeneous medium. The results are interpreted by a “matrix effect” which is enhanced in those mixtures in which the precipitated polymer particles are swollen to a larger extent by the reacting mixture.