Anionic Copolymerization of Acrylonitrile with Ethyl Acrylate under the Action of the Initiating System of 1,4-Diazabicyclo[2.2.2]Octane – Ethylene Oxide

It was found, studying acrylonitrile copolymerization with ethyl acrylate in dimethyl sulfoxide under the action of anionic initiating system of 1,4-diazabicyclo [2.2.2] octane – ethylene oxide, that the obtained copolymers have a branched structure. An increase in the molar fraction of ethyl acrylate in the reaction medium leads to a decrease in the initial rate of acrylonitrile polymerization. Thermal behavior of copolymer samples was investigated; it was found that ethyl acrylate, being introduced into the polyacrylonitrile structure, both reduces thermal effects related to the reactions taking place during heat treatment of copolymers, and increases the half-width of the heat release peak.

Download Full-text

Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities

Journal of Analytical Science & Technology ◽

10.1186/s40543-020-00238-2 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Khémesse Kital ◽

Moumouny Traoré ◽

Diégane Sarr ◽

Moussa Mbaye ◽

Mame Diabou Gaye Seye ◽

...

Keyword(s):

Complex Formation ◽

Thermodynamic Parameters ◽

Initial Rate ◽

Reaction Medium ◽

Standard Entropy ◽

Step Size ◽

Formation Reaction ◽

Different Temperatures ◽

Kinetics Of ◽

Complex Formation Process

Abstract The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the association constant (Ka) between orthophthalaldehyde and agmatine was determined at different temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°),and Gibbs energy (∆G) were calculated, where a positive value of ΔH° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition, the low value of ΔS°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium. Furthermore, the negative values of ΔG between −35.62 kJ/mol and −26.02 kJ/mol show that the complex formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and AGM were determined as follows: when the initial concentration of AGM (5 × 10−6 M) is equal to that of the OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 × 10−7Mmin−1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work shows that the excess of OPA accelerates the formation reaction of the complex.

Download Full-text

Reactivity ratios for the anionic copolymerization of ethylene oxide and butylene oxide in bulk

European Polymer Journal ◽

10.1016/0014-3057(93)90094-v ◽

1993 ◽

Vol 29 (2-3) ◽

pp. 281-286 ◽

Cited By ~ 9

Author(s):

Stewart Dickson ◽

Ga-Er Yu ◽

Frank Heatley ◽

Colin Booth

Keyword(s):

Ethylene Oxide ◽

Reactivity Ratios ◽

Anionic Copolymerization

Download Full-text

Fast Access to Amphiphilic Multiblock Architectures by the Anionic Copolymerization of Aziridines and Ethylene Oxide

Journal of the American Chemical Society ◽

10.1021/jacs.8b08054 ◽

2018 ◽

Vol 140 (41) ◽

pp. 13407-13412 ◽

Cited By ~ 26

Author(s):

Tassilo Gleede ◽

Elisabeth Rieger ◽

Jan Blankenburg ◽

Katja Klein ◽

Frederik R. Wurm

Keyword(s):

Ethylene Oxide ◽

Anionic Copolymerization ◽

Fast Access

Download Full-text

Rheological, Microstructural and Thermal Properties of Magnetic Poly(Ethylene Oxide)/Iron Oxide Nanocomposite Hydrogels Synthesized Using a One-Step Gamma-Irradiation Method

Nanomaterials ◽

10.3390/nano10091823 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1823

Author(s):

Ivan Marić ◽

Nataša Šijaković Vujičić ◽

Anđela Pustak ◽

Marijan Gotić ◽

Goran Štefanić ◽

...

Keyword(s):

Iron Oxide ◽

Ethylene Oxide ◽

Molar Fraction ◽

Magnetic Iron Oxide Nanoparticles ◽

Γ Irradiation ◽

Nanocomposite Hydrogels ◽

One Step ◽

Poly Ethylene Oxide ◽

Poly Ethylene ◽

The One

Magnetic polymer gels are a new promising class of nanocomposite gels. In this work, magnetic PEO/iron oxide nanocomposite hydrogels were synthesized using the one-step γ-irradiation method starting from poly(ethylene oxide) (PEO) and iron(III) precursor alkaline aqueous suspensions followed by simultaneous crosslinking of PEO chains and reduction of Fe(III) precursor. γ-irradiation dose and concentrations of Fe3+, 2-propanol and PEO in the initial suspensions were varied and optimized. With 2-propanol and at high doses magnetic gels with embedded magnetite nanoparticles were obtained, as confirmed by XRD, SEM and Mössbauer spectrometry. The quantitative determination of γ-irradiation generated Fe2+ was performed using the 1,10-phenanthroline method. The maximal Fe2+ molar fraction of 0.55 was achieved at 300 kGy, pH = 12 and initial 5% of Fe3+. The DSC and rheological measurements confirmed the formation of a well-structured network. The thermal and rheological properties of gels depended on the dose, PEO concentration and initial Fe3+ content (amount of nanoparticles synthesized inside gels). More amorphous and stronger gels were formed at higher dose and higher nanoparticle content. The properties of synthesized gels were determined by the presence of magnetic iron oxide nanoparticles, which acted as reinforcing agents and additional crosslinkers of PEO chains thus facilitating the one-step gel formation.

Download Full-text

Miscible binary blends of poly(ethylene oxide) and poly(ether sulphone). Part 1: crystallization kinetics, morphology and thermal behavior

Polymer ◽

10.1016/s0032-3861(98)00809-x ◽

1999 ◽

Vol 40 (21) ◽

pp. 5907-5917 ◽

Cited By ~ 20

Author(s):

G. Dreezen ◽

Z. Fang ◽

G. Groeninckx

Keyword(s):

Ethylene Oxide ◽

Thermal Behavior ◽

Crystallization Kinetics ◽

Binary Blends ◽

Poly Ethylene Oxide ◽

Poly Ethylene

Download Full-text

Über die pH- und Temperatur-Abhängigkeit des thermischen Zerfalls von Poliovirus-Teilchen in Nucleinsäure und leere Proteinhüllen

Zeitschrift für Naturforschung B ◽

10.1515/znb-1966-0410 ◽

1966 ◽

Vol 21 (4) ◽

pp. 357-361 ◽

Cited By ~ 7

Author(s):

O. Drees ◽

K. D. Demme

Keyword(s):

Heat Treatment ◽

Initial Rate ◽

Concentrated Suspensions ◽

Virus Particles ◽

Ph Values ◽

Intact Virus ◽

Wide Range ◽

Ultracentrifugal Analysis ◽

Increasing Temperature ◽

Kinetics Of

The intact virus particles of highly purified, concentrated suspensions of poliovirus have been disintegrated into free nucleic acid and empty protein shells (78 S protein) by moderate heat treatment at various temperatures and pH values. The kinetics of this degradation has been followed by ultracentrifugal analysis.With increasing temperature between 35° and 50 °C and with increasing pH of the suspension medium between 7 and 8, the rate of degradation increased. For any particular conditions the initial rate was not maintained, and after a certain time there was little further degradation if conditions remained unaltered. Some particles with the sedimentation characteristics of poliovirus were resistant to disintegration under the same conditions which led to the breakdown of the bulk of the virus. The proportion of this “stable fraction” varied within a wide range from one preparation to another and decreased with increasing temperature and with increasing pʜ.

Download Full-text

Nano-Crystalline Barium Hexaferrite Powders Prepared by Mechanical Alloying Using Acetate Precursor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.610 ◽

2008 ◽

Vol 368-372 ◽

pp. 610-612 ◽

Cited By ~ 3

Author(s):

M. Honarvar Nazari ◽

Abolghasem Ataie ◽

S.A. Seyyed Ebrahimi

Keyword(s):

Heat Treatment ◽

Magnetic Properties ◽

Phase Composition ◽

Mechanical Alloying ◽

Thermal Behavior ◽

Crystallite Size ◽

Barium Hexaferrite ◽

Subsequent Heat Treatment ◽

Molar Ratios ◽

Nano Crystalline

Nano-crystalline barium hexaferrite powders have been prepared by mechanical alloying of nFe2O3+Ba(CH3COO)2 with Fe/Ba molar ratios of 10-12 and subsequent heat treatment. Thermal behavior, phase composition, morphology and magnetic properties of samples were studied using DTA/TGA, XRD, SEM and VSM, respectively. Nano-crystalline Ba-hexaferrite with a mean crystallite size of 46 nm and magnetic properties as high as Ms = 73.9 A.m2/kg and Hci = 334.2 kA/m was formed for mixture of 5.5Fe2O3+Ba(CH3COO)2 which was milled for 48 h and then annealed at 1100 °C.

Download Full-text