Vadim Krongauz - Academia.edu (original) (raw)

Papers by Vadim Krongauz

Journal of the Korean Vacuum Society, 1998

Photploymer films are widely used in printing and electronic industries, and their usage is expan... more Photploymer films are widely used in printing and electronic industries, and their usage is expanding to encompass holography, data storage and data processing, optical waveguides and compact disks, etc. One of widely used photoplymerization initiator, 20chloro-hexaarylbiimidazole (o-Cl-HABI), is studied by laser flash photolysis in dichloromethane solution in the absence and presence of the visible light photosensitizing dye, 2, 5-bis[(2, 3, 6, 7 -tetrahydro- 1H, 5H -benzo [i, j,] quinolizin -1-yl) methylene]-cyclopenta-none, (JAW). In the presence of JAW, an increase in triarylimidazolyl radicals L.formation is observed in relative to the absence of JAW. The mechanism of this photosensitizing dissociation is concluded as the dissociation of the o-Cl-HABI radical anion formed by the electron transfer from excited singlet state of JAW to o-Cl-HABI. The observed formation of L.radicals exhibits a linear dependence on o-Cl-HABI concentration. The rate constant of electron transfer obtained from this dependence is equal to (1.00.2) x . No reaction between the excited triplet state of JAW and o-Cl-HABI is found.

Journal of Applied Polymer Science, Aug 15, 1997

Ion-exchange kinetics within a conventional strong base resin, Dowexl-8X®, and a resin with unifo... more Ion-exchange kinetics within a conventional strong base resin, Dowexl-8X®, and a resin with uniform particle size, Dowex® Monosphere® Tough Gel® TG550A®, were investigated using neutron activation analysis and radio-tracer techniques. The kinetics of ion exchange were measured in a batch and in a shallow-bed flow system. The experimental data were compared with the results of model computations. The diffusivities of several anions within TG550A and Dowexl-8X were deduced. It was found that at 25°C Br - , Cl - , OH - , and Na + diffuse within TG550A with the diffusion coefficients D Br- = 6.0 X 10 -7 cm 2 /s, D Cl- = 1.2 x 10 -6 cm 2 /s, D OH- = 7.0 X 10 -8 cm 2 / s, and D Na+ = 5 X 10 -7 cm 2 /s. Diffusion of anions within a conventional resin, Dowexl®, was slower: D Br - = 3.5 X 10 -7 cm 2 /s, D Cl- = 6 x 10 -7 cm 2 /s, D OH- = 2.7 X 10 -8 cm 2 / s, and D Na+ = 5 X 10 -7 cm 2 /s. A higher rate of ion diffusion and the bead-size uniformity may make monodisperse Dowex Monosphere Tough Gel TG550A resin attractive for analytical applications. The difference in properties between conventional and monodisperse resins is not sufficient to affect the large volume applications of resins.

Journal of Thermal Analysis and Calorimetry, May 5, 2021

Kinetics of bis(2-diethylhexyl)phthalate plasticized poly(vinyl chloride) (PVC) autohesion develo... more Kinetics of bis(2-diethylhexyl)phthalate plasticized poly(vinyl chloride) (PVC) autohesion development was monitored at 373 K, 393 K, 413 K. Three regions of bonding kinetics were observed (first time) at all temperatures: adhesion increase after initial contact, constant adhesion plateau, long contact time adhesion increase. Initial adhesion increase resulted from plasticizer diffusion into interface and capillary attraction, activation energy, Ea = 66 kJ mol−1. Plateau in adhesion kinetics is consistent with polymer segments diffusion across interface; duration decreased with temperature increase, yielding Ea = 113 kJ mol−1. Adhesion at plateau increased linearly with temperature increase, indicating Van der Waals attraction between the PVC macromolecules in interface. Final adhesion increase was stipulated by macromolecular segments diffusion into and entanglement within interface, Ea = 109 kJ mol−1. Scanning electron and optical microscopy confirmed plasticizer and polymer diffusion into interface (width up to 3.5 µm). PVC segments diffusivities in plasticized PVC were derived: 1.8 × 10−13 cm2 s−1 at 373 K, 1.1 × 10−12 cm2 s−1 at 393 K, 6.3 × 10−12 cm2 s−1 at 413 K.

Springer eBooks, 1995

... Photonique et Laser (COPL), Faculte des Sciences et Genie, Pavilion Vachon, Universite Laval,... more ... Photonique et Laser (COPL), Faculte des Sciences et Genie, Pavilion Vachon, Universite Laval, Quebec, CANADA G1K 7P4 ix ... Naitoh, Chiba University, Department of Image Science, Faculty of Engineering, Yayoi-Cho 1-33, Inage-ku Chiba, 263, JAPAN Alexander D. Trifunac ...

Journal of Applied Polymer Science, Nov 30, 2022

Chemischer Informationsdienst, Aug 16, 1983

ChemInform Abstract (in the temp. range 295-673 K, but H-abstraction is found only at temp. above... more ChemInform Abstract (in the temp. range 295-673 K, but H-abstraction is found only at temp. above 548 K).

Thermogravimetrically obtained temperature dependences of kinetics of degradation (in nitrogen an... more Thermogravimetrically obtained temperature dependences of kinetics of degradation (in nitrogen and oxygen) of a series of crosslinked polyurethane acrylates, kinetics of solvent diffusion through the same crosslinked urethane acrylates, and kinetics of sublimation of a series of azepine derivatives were re-evaluated. Arrhenius equation parameters for these series of processes were deduced. In all cases, a linear dependence of activation energies, Ea, and pre-exponential factors, A0, (compensation effect) was observed. Sublimation of azepines occurred with isoconversion temperature of ≈ 333 K and lnA0 = 0.19Ea + 7.48, with regression coefficient, R2 = 0.99. The overall linear fit of polyurethane acrylates’ degradation kinetics yielded compensation effect parameters almost identical for degradation in nitrogen and air: in O2 ln A0- = 0.12Ea + 3.2 with R2 = 0.97; in N2 lnA0 = 0.12Ea + 3.1 with R2 = 0.82. The compensation effect equation for diffusion-controlled evaporation of N-methyl pyrrolidone from the poly(urethane acrylates) with different crosslink densities was ln D0 = 0.38 Ea - 0.57 with R2 = 0.98. Semi-empirical Lawson–Keyes equations of proportionality of activation enthalpy (and activation energy) and entropy of the process to activated volume were derived. Process entropy and enthalpy compensation relation existence was consequently confirmed for condense phase processes. Other theoretical approaches explaining compensation effect were discussed and found consistent with the explanation of kinetic compensation effect presented. Keywords: Kinetics, Diffusion, Sublimation, Polymer degradation , Thermogravimetric analysis, Kinetic compensation effect, Lawson, Keyes, Eyring

L'invention concerne un dispositif medical, tel qu'un dispositif d'acces vasculaire, ... more L'invention concerne un dispositif medical, tel qu'un dispositif d'acces vasculaire, destine a permettre d'acceder a une voie d'ecoulement de fluide medical pour l'introduction ou le prelevement de fluides medicaux dans et a partir d'une voie d'ecoulement. Le dispositif d'acces comprend un indicateur destine a fournir une indication visuelle lorsque le dispositif d'acces a ete expose a un agent antiseptique.

ABSTRACT The method of the efficient analysis of di(2-diethylhexyl) phthalate, tri(2-ethylhexyl) ... more ABSTRACT The method of the efficient analysis of di(2-diethylhexyl) phthalate, tri(2-ethylhexyl) trimellitate, di(2-ethylhexyl) terephthalate, and other phthalate plasticizers concentrations in plasticized poly(vinyl chloride) (PVC) was developed. The method is based on quantitative dissolution of the PVC sample in methyl ethyl ketone with the consequent precipitation of PVC with hexane and concentration of phthalate in an organic layer. A capillary column-based gas chromatographic technique for phthalates separation and quantification was developed and used in conjunction with the PVC and phthalates dissolution technique. The developed method of phthalate plasticizers analysis proved to be relatively fast, reproducible, and straightforward. J. VINYL ADDIT. TECHNOL., 2014. © 2014 Society of Plastics Engineers

Journal of Thermal Analysis and Calorimetry

The Journal of Physical Chemistry

Page 1. J. Phys. Chem. 1992, 96, 207-211 207 Photodissociation of Hexaarylblimidazole. 2. Direct ... more Page 1. J. Phys. Chem. 1992, 96, 207-211 207 Photodissociation of Hexaarylblimidazole. 2. Direct and Sensitized Dissociation+ An-Dong Liu, Alexander D. Trifunac,* Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 and Vadim V. Krongauz* ...

Polymer

Influence of thiols on kinetics of acrylate radical photopolymerization in the presence and absen... more Influence of thiols on kinetics of acrylate radical photopolymerization in the presence and absence of photoinitiators was studied. The kinetics was monitored by infrared absorption and photo-differential scanning calorimetry. It was found that aromatic thiols at concentrations, , 0.5% (,0.05 M), can accelerate radical photopolymerization. Initiation of radical photopolymerization by some aromatic thiols in the absence of conventional photoinitiators was observed. As well as expected inhibition of photopolymerization at higher concentration of aromatic thiols due to chain transfer was detected. A ground state charge-transfer complex formation between thiols and benzoin based photoinitiators was detected. Mechanism of thiols participation in photopolymerization involving reduction of oxygen inhibition and dissociation of charge-transfer complexes is discussed. Published by Elsevier Science Ltd.

The Journal of Physical Chemistry

... (4) Wilks, MA J.; Willis, M. R. J. Chem. Soc. 1966, 1526. (5) Prokhoda, AL; Krongauz, VA Khim... more ... (4) Wilks, MA J.; Willis, M. R. J. Chem. Soc. 1966, 1526. (5) Prokhoda, AL; Krongauz, VA Khim. Vys. Energ. 1%9,3 (a), 495. (6) Bazov, VP; Parshutkin, A. A.; Krongauz, VA Khim. Vys. Energ. (7) Prokhoda, AL; Krongauz, VA Khim. Vys. Energ. 1970,4 (2), 176. ...

The Journal of Physical Chemistry

Page 1. 212 J. Phys. Chem. 1992, 96, 212-217 Solvent Effects on the Photochemistry of a Ketocyani... more Page 1. 212 J. Phys. Chem. 1992, 96, 212-217 Solvent Effects on the Photochemistry of a Ketocyanine Dye and Its Functional Analogue, Michler's Ketonet Mary V. Bamabas, Andong Liu, AD Trifunac,* Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 ...

The Journal of Physical Chemistry

ABSTRACT

Journal of the Korean Vacuum Society, 1998

Photploymer films are widely used in printing and electronic industries, and their usage is expan... more Photploymer films are widely used in printing and electronic industries, and their usage is expanding to encompass holography, data storage and data processing, optical waveguides and compact disks, etc. One of widely used photoplymerization initiator, 20chloro-hexaarylbiimidazole (o-Cl-HABI), is studied by laser flash photolysis in dichloromethane solution in the absence and presence of the visible light photosensitizing dye, 2, 5-bis[(2, 3, 6, 7 -tetrahydro- 1H, 5H -benzo [i, j,] quinolizin -1-yl) methylene]-cyclopenta-none, (JAW). In the presence of JAW, an increase in triarylimidazolyl radicals L.formation is observed in relative to the absence of JAW. The mechanism of this photosensitizing dissociation is concluded as the dissociation of the o-Cl-HABI radical anion formed by the electron transfer from excited singlet state of JAW to o-Cl-HABI. The observed formation of L.radicals exhibits a linear dependence on o-Cl-HABI concentration. The rate constant of electron transfer obtained from this dependence is equal to (1.00.2) x . No reaction between the excited triplet state of JAW and o-Cl-HABI is found.

Journal of Applied Polymer Science, Aug 15, 1997

Ion-exchange kinetics within a conventional strong base resin, Dowexl-8X®, and a resin with unifo... more Ion-exchange kinetics within a conventional strong base resin, Dowexl-8X®, and a resin with uniform particle size, Dowex® Monosphere® Tough Gel® TG550A®, were investigated using neutron activation analysis and radio-tracer techniques. The kinetics of ion exchange were measured in a batch and in a shallow-bed flow system. The experimental data were compared with the results of model computations. The diffusivities of several anions within TG550A and Dowexl-8X were deduced. It was found that at 25°C Br - , Cl - , OH - , and Na + diffuse within TG550A with the diffusion coefficients D Br- = 6.0 X 10 -7 cm 2 /s, D Cl- = 1.2 x 10 -6 cm 2 /s, D OH- = 7.0 X 10 -8 cm 2 / s, and D Na+ = 5 X 10 -7 cm 2 /s. Diffusion of anions within a conventional resin, Dowexl®, was slower: D Br - = 3.5 X 10 -7 cm 2 /s, D Cl- = 6 x 10 -7 cm 2 /s, D OH- = 2.7 X 10 -8 cm 2 / s, and D Na+ = 5 X 10 -7 cm 2 /s. A higher rate of ion diffusion and the bead-size uniformity may make monodisperse Dowex Monosphere Tough Gel TG550A resin attractive for analytical applications. The difference in properties between conventional and monodisperse resins is not sufficient to affect the large volume applications of resins.

Journal of Thermal Analysis and Calorimetry, May 5, 2021

Kinetics of bis(2-diethylhexyl)phthalate plasticized poly(vinyl chloride) (PVC) autohesion develo... more Kinetics of bis(2-diethylhexyl)phthalate plasticized poly(vinyl chloride) (PVC) autohesion development was monitored at 373 K, 393 K, 413 K. Three regions of bonding kinetics were observed (first time) at all temperatures: adhesion increase after initial contact, constant adhesion plateau, long contact time adhesion increase. Initial adhesion increase resulted from plasticizer diffusion into interface and capillary attraction, activation energy, Ea = 66 kJ mol−1. Plateau in adhesion kinetics is consistent with polymer segments diffusion across interface; duration decreased with temperature increase, yielding Ea = 113 kJ mol−1. Adhesion at plateau increased linearly with temperature increase, indicating Van der Waals attraction between the PVC macromolecules in interface. Final adhesion increase was stipulated by macromolecular segments diffusion into and entanglement within interface, Ea = 109 kJ mol−1. Scanning electron and optical microscopy confirmed plasticizer and polymer diffusion into interface (width up to 3.5 µm). PVC segments diffusivities in plasticized PVC were derived: 1.8 × 10−13 cm2 s−1 at 373 K, 1.1 × 10−12 cm2 s−1 at 393 K, 6.3 × 10−12 cm2 s−1 at 413 K.

Springer eBooks, 1995

... Photonique et Laser (COPL), Faculte des Sciences et Genie, Pavilion Vachon, Universite Laval,... more ... Photonique et Laser (COPL), Faculte des Sciences et Genie, Pavilion Vachon, Universite Laval, Quebec, CANADA G1K 7P4 ix ... Naitoh, Chiba University, Department of Image Science, Faculty of Engineering, Yayoi-Cho 1-33, Inage-ku Chiba, 263, JAPAN Alexander D. Trifunac ...

Journal of Applied Polymer Science, Nov 30, 2022

Chemischer Informationsdienst, Aug 16, 1983

ChemInform Abstract (in the temp. range 295-673 K, but H-abstraction is found only at temp. above... more ChemInform Abstract (in the temp. range 295-673 K, but H-abstraction is found only at temp. above 548 K).

Thermogravimetrically obtained temperature dependences of kinetics of degradation (in nitrogen an... more Thermogravimetrically obtained temperature dependences of kinetics of degradation (in nitrogen and oxygen) of a series of crosslinked polyurethane acrylates, kinetics of solvent diffusion through the same crosslinked urethane acrylates, and kinetics of sublimation of a series of azepine derivatives were re-evaluated. Arrhenius equation parameters for these series of processes were deduced. In all cases, a linear dependence of activation energies, Ea, and pre-exponential factors, A0, (compensation effect) was observed. Sublimation of azepines occurred with isoconversion temperature of ≈ 333 K and lnA0 = 0.19Ea + 7.48, with regression coefficient, R2 = 0.99. The overall linear fit of polyurethane acrylates’ degradation kinetics yielded compensation effect parameters almost identical for degradation in nitrogen and air: in O2 ln A0- = 0.12Ea + 3.2 with R2 = 0.97; in N2 lnA0 = 0.12Ea + 3.1 with R2 = 0.82. The compensation effect equation for diffusion-controlled evaporation of N-methyl pyrrolidone from the poly(urethane acrylates) with different crosslink densities was ln D0 = 0.38 Ea - 0.57 with R2 = 0.98. Semi-empirical Lawson–Keyes equations of proportionality of activation enthalpy (and activation energy) and entropy of the process to activated volume were derived. Process entropy and enthalpy compensation relation existence was consequently confirmed for condense phase processes. Other theoretical approaches explaining compensation effect were discussed and found consistent with the explanation of kinetic compensation effect presented. Keywords: Kinetics, Diffusion, Sublimation, Polymer degradation , Thermogravimetric analysis, Kinetic compensation effect, Lawson, Keyes, Eyring

L'invention concerne un dispositif medical, tel qu'un dispositif d'acces vasculaire, ... more L'invention concerne un dispositif medical, tel qu'un dispositif d'acces vasculaire, destine a permettre d'acceder a une voie d'ecoulement de fluide medical pour l'introduction ou le prelevement de fluides medicaux dans et a partir d'une voie d'ecoulement. Le dispositif d'acces comprend un indicateur destine a fournir une indication visuelle lorsque le dispositif d'acces a ete expose a un agent antiseptique.

ABSTRACT The method of the efficient analysis of di(2-diethylhexyl) phthalate, tri(2-ethylhexyl) ... more ABSTRACT The method of the efficient analysis of di(2-diethylhexyl) phthalate, tri(2-ethylhexyl) trimellitate, di(2-ethylhexyl) terephthalate, and other phthalate plasticizers concentrations in plasticized poly(vinyl chloride) (PVC) was developed. The method is based on quantitative dissolution of the PVC sample in methyl ethyl ketone with the consequent precipitation of PVC with hexane and concentration of phthalate in an organic layer. A capillary column-based gas chromatographic technique for phthalates separation and quantification was developed and used in conjunction with the PVC and phthalates dissolution technique. The developed method of phthalate plasticizers analysis proved to be relatively fast, reproducible, and straightforward. J. VINYL ADDIT. TECHNOL., 2014. © 2014 Society of Plastics Engineers

Journal of Thermal Analysis and Calorimetry

The Journal of Physical Chemistry

Page 1. J. Phys. Chem. 1992, 96, 207-211 207 Photodissociation of Hexaarylblimidazole. 2. Direct ... more Page 1. J. Phys. Chem. 1992, 96, 207-211 207 Photodissociation of Hexaarylblimidazole. 2. Direct and Sensitized Dissociation+ An-Dong Liu, Alexander D. Trifunac,* Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 and Vadim V. Krongauz* ...

Polymer

Influence of thiols on kinetics of acrylate radical photopolymerization in the presence and absen... more Influence of thiols on kinetics of acrylate radical photopolymerization in the presence and absence of photoinitiators was studied. The kinetics was monitored by infrared absorption and photo-differential scanning calorimetry. It was found that aromatic thiols at concentrations, , 0.5% (,0.05 M), can accelerate radical photopolymerization. Initiation of radical photopolymerization by some aromatic thiols in the absence of conventional photoinitiators was observed. As well as expected inhibition of photopolymerization at higher concentration of aromatic thiols due to chain transfer was detected. A ground state charge-transfer complex formation between thiols and benzoin based photoinitiators was detected. Mechanism of thiols participation in photopolymerization involving reduction of oxygen inhibition and dissociation of charge-transfer complexes is discussed. Published by Elsevier Science Ltd.

The Journal of Physical Chemistry

... (4) Wilks, MA J.; Willis, M. R. J. Chem. Soc. 1966, 1526. (5) Prokhoda, AL; Krongauz, VA Khim... more ... (4) Wilks, MA J.; Willis, M. R. J. Chem. Soc. 1966, 1526. (5) Prokhoda, AL; Krongauz, VA Khim. Vys. Energ. 1%9,3 (a), 495. (6) Bazov, VP; Parshutkin, A. A.; Krongauz, VA Khim. Vys. Energ. (7) Prokhoda, AL; Krongauz, VA Khim. Vys. Energ. 1970,4 (2), 176. ...

The Journal of Physical Chemistry

Page 1. 212 J. Phys. Chem. 1992, 96, 212-217 Solvent Effects on the Photochemistry of a Ketocyani... more Page 1. 212 J. Phys. Chem. 1992, 96, 212-217 Solvent Effects on the Photochemistry of a Ketocyanine Dye and Its Functional Analogue, Michler's Ketonet Mary V. Bamabas, Andong Liu, AD Trifunac,* Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 ...

The Journal of Physical Chemistry

ABSTRACT