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  • 1. Amme, Marcus
    et al.
    Pehrman, Reijo
    Deutsch, Rudolf
    Roth, Olivia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Combined effects of Fe(II) and oxidizing radiolysis products on UO2 and PuO2 dissolution in a system containing solid UO2 and PuO22012In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 430, no 1-3, p. 1-5Article in journal (Refereed)
    Abstract [en]

    The stability of UO2 spent nuclear fuel in an oxygen-free geological repository depends on the absence of oxidizing reaction partners in the near field. This work investigates the reactions between the products of water radiolysis by alpha radiation and Fe(II) an the effect on UO2 dissolution. Solid (PuO2)-Pu-238 powder and UO2 pellet were allowed to react in Fe(II) solution in oxygen-free batch reactor tests and kinetics of the subsequent redox reactions were measured. Depending on the concentration of Fe(II) (tests with 10(-5) and 10(-4) mol L-1 were made), the induced redox reactions took place between 20 and 400 h. Dissolved uranium concentrations went first through a minimum caused by reduction, followed by a maximum caused by radiolytic oxidation, and eventually reached another minimum, probably due to sorption on precipitated Fe(III). Plutonium concentrations were decreasing steadily after going through a maximum about 70 h from the start of the experiments. The results show that in the presence of the strong alpha-radiolytic field induced by the presence of solid Pu-238, the behavior of the system is largely governed by Fe(II) as it controls the H2O2 concentration, reduces U(VI) in solution and drives the Fenton reaction leading to the oxidation of Pu(IV).

  • 2.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Radiation induced dissolution of (U, Gd)O-2 pellets in aqueous solution - A comparison to standard UO2 pellets2019In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 514, p. 216-223Article in journal (Refereed)
    Abstract [en]

    The behavior of spent nuclear fuel exposed to groundwater is crucial in the safety assessment of a deep geological repository for spent nuclear fuel. For this reason, leaching experiments on spent nuclear fuel as well as non-radioactive analogues have been conducted for several decades. Although the processes involved can be considered to be fairly well understood, there is a need for further experimental studies whenever new fuel types are introduced. Fuels with burnable absorbers are now in use but very little is known about their behavior under repository conditions. In this work, the impact of burnable absorbers doping (Gd, 3-8%wt.) on the oxidative dissolution of UO2 in an aqueous system was studied in H2O2 and gamma-irradiation induced dissolution experiments. The results showed a significant decrease in uranium dissolution and lower reactivity towards H2O2 for (U,Gd)O-2 pellets compared to standard UO2. The resulting decrease in the final oxidative dissolution yield was mainly attributed to decreased redox reactivity of the UO2-matrix upon doping. The results of the gamma radiation exposures display an even larger effect of Gd-doping. These findings indicate that other processes are involved in the radiation-induced dissolution of Gd-doped UO2 compared to pure UO2. 

  • 3.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Radiation induced dissolution of (U, Gd)O2 pellets in aqueous solution: A comparison to standard UO2 pelletsManuscript (preprint) (Other academic)
    Abstract [en]

    In this work, the impact of burnable absorbers doping (Gd, 3-8%wt.) on the oxidative dissolution of UO2 in an aqueous system was studied by H2O2 and γ-irradiation induced dissolution experiments. The results showed a significant decrease in uranium dissolution and higher stability towards H2O2 for (U,Gd)O2 pellets compared to standard UO2. The resulting decrease in the final oxidative dissolution yield was mainly attributed to decreased redox reactivity of the UO2-matrix upon doping. During gamma radiation induced experiments, the difference in uranium release was even more pronounced compared to H2O2 induced dissolution experiments.

  • 4.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Kumagai, Yuta
    Japan Atomic Energy Agency.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Impact of stoichiometry on the reactivity of UO2 towards radiolytic oxidantsManuscript (preprint) (Other academic)
  • 5.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kumagai, Yuta
    Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, Nakagun, Japan.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    The role of surface-bound hydroxyl radicals in the reaction between H2O2 and UO22018In: Journal of coordination chemistry (Print), ISSN 0095-8972, E-ISSN 1029-0389, Vol. 71, no 11-13, p. 1799-1807Article in journal (Refereed)
    Abstract [en]

    In this work, we have studied the reaction between H2O2 and UO2 with particular focus on the nature of the hydroxyl radical formed as an intermediate. Experiments were performed to study the kinetics of H2O2 consumption and uranium dissolution at different initial H2O2 concentrations. The results show that the consumption rates at a given H2O2 concentration are different depending on the initial H2O2 concentration. This is attributed to an alteration of the reactive interface, likely caused by blocking of surface sites by oxidized U/surface-bound hydroxyl radicals. The dissolution yield given by the amount of dissolved uranium divided by the amount of consumed hydrogen peroxide was used to compare the different cases. For all initial H2O2 concentrations, the dissolution yield increases with reaction time. The final dissolution yield decreases with increasing initial H2O2 concentration. This is expected from the mechanism of catalytic decomposition of H2O2 on oxide surfaces. As the experiments were performed in solutions containing 10mM H2O2 and a strong concentration dependence was observed in the 0.2-2.0mM H2O2 concentration range, we conclude that the intermediate hydroxyl radical is surface bound rather than free.

  • 6.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Sundin, Sara
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Effect of bentonite on radiation induced dissolution of UO2 in an aqueous system2014In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 447, no 1-3, p. 73-76Article in journal (Refereed)
    Abstract [en]

    In order to elucidate the impact of bentonite on the process of radiation induced oxidative dissolution of UO2 in an aqueous system, the dissolution of U(VI) and consumption of H2O2 over time has been studied. In addition, γ-irradiation experiments were performed to study a more relevant and complex system, serving as a comparison with the previously stated system. In both cases, the experiments revealed that the presence of bentonite in water could either delay or prevent in part the release of uranium to the environment. The cause is mainly attributed to the scavenging of radiolytic oxidants rather than to the adsorption of uranium onto bentonite.

  • 7.
    Bergenudd, Helena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Coullerez, Geraldine
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Malmström, Eva E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Solvent Effects on ATRP of Oligo(ethylene glycol) Methacrylate. Exploring the Limits of Control2009In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 42, no 9, p. 3302-3308Article in journal (Refereed)
    Abstract [en]

    Five copper complexes in combination with six monomer-solvent mixtures have been used to investigate the solvent effects oil ATRP of oligo(ethylene glycol) methacrylate (OEGMA). The redox properties of the copper complexes in OEGMA-solvent mixtures and the apparent rate constants (k(p)(app)) for ATRP of OEGMA were correlated to the degree of control over the polymerizations. Based on this correlation, a general discussion of the limits of control in ATRIP is carried out. One of the key parameters for control in ATRP is the propagation rate constant, making the choice of monomer essential for the design of ail ATRP system. Also, the solvent effects oil the ATRP equilibrium constant (K-ATRP) affect the limit of control (i.e., the apparent rate constant above which control is lost). The choice of copper complex is also more important than the choice of solvent for the design of a well-controlled ATRP system.

  • 8.
    Bergenudd, Helena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Investigation of iron complexes in ATRP: Indications of different iron species in normal and reverse ATRP2011In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 346, no 1-2, p. 20-28Article in journal (Refereed)
    Abstract [en]

    In an attempt to correlate the ATRP kinetics and the redox properties of the mediator, eight iron complexes with nitrogen, phosphorous and carboxylic acid containing ligands were investigated by electrochemical measurements and by using them as mediators in normal and reverse ATRP of MMA in DMF. The redox properties of the iron complexes in DMF, measured by cyclic voltammetry, did not differ significantly, which was reflected in the ATRP kinetics as the apparent rate constants were practically the same with all the complexing ligands. The degree of control over the polymerization was, however, much improved in reverse ATRP as compared to normal ATRP. In this ATRP system, the ligand type is not crucial for the redox or polymerization properties. Several observations indicate that the iron species in the two systems were not the same, the Fe(III) species resulting from oxidation of Fe(II) in normal ATRP is different from the starting Fe(III) species in reverse ATRP.

  • 9.
    Bergenudd, Helena
    et al.
    KTH, School of Chemical Science and Engineering (CHE).
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE).
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE).
    POLY 104-Predicting the level of control for ATRP systems2009In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 238Article in journal (Other academic)
  • 10.
    Bergenudd, Helena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Predicting the Limit of Control in the ATRP Process: Results from Kinetic Simulations2011In: Macromolecular Theory and Simulations, ISSN 1022-1344, E-ISSN 1521-3919, Vol. 20, no 9, p. 814-825Article in journal (Refereed)
    Abstract [en]

    Kinetic simulations are reported, where the ATRP equilibrium constant K(ATRP) is varied and the rates and degree of control in different ATRP systems are evaluated. The apparent rate constant k(app) increases with increasing K(ATRP), but a maximum is reached. The limit of control is passed before the maximum, i.e. when K(ATRP) is increased further, apparent first-order kinetics and well-controlled molecular weights will no longer be obtained. The equilibrium constant at which the limit of control is reached varies linearly with the propagation rate constant. This enables the design of well controlled ATRP systems. The influence of the conversion and chain length dependence of the termination rate constant on the simulation results is discussed.

  • 11.
    Bergenudd, Helena
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Nyström, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Heterogeneous iron(II)-chloride mediated radical polymerization of styrene2009In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 306, no 1-2, p. 69-76Article in journal (Refereed)
    Abstract [en]

    In an attempt to perform atom transfer radical polymerization (ATRP) with a more environmentally friendly mediator, polymerization of styrene in the presence of iron(II)-chloride and EDTA was explored from a mechanistic point of view. The presence of EDTA, which normally can form a complex with FeCl2, had no influence on the polymerization results as both the mediator and EDTA were insoluble in the polymerization medium. A mechanism is suggested for the heterogeneous polymerization of styrene mediated by iron (II)-chloride in p-xylene at 50 °C. Varying the mediator amount more than 10-fold revealed that the rate limiting step at low mediator amounts was the adsorption of the initiator or dormant polymer to the mediator surface, whereas at higher mediator amounts, the rate limiting step was instead the activation step in the ATRP equilibrium. The mechanism changed to free radical polymerization in solution at a certain conversion, resulting in lower apparent rate constant and an increased amount of transfer and termination reactions. Chain extension with MMA showed that a significant proportion of the polymer chain ends were active also at high conversions.

  • 12.
    Bjorkbacka, Asa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Role of the Oxide Layer in Radiation-Induced Corrosion of Copper in Anoxic Water2016In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 21, p. 11450-11455Article in journal (Refereed)
    Abstract [en]

    The influence of a pregrown copper oxide layer on radiation-induced corrosion of polished copper in pure anoxic water has been explored. The resulting amount of copper oxide formed during corrosion was measured with cathodic reduction, and the concentration of dissolved copper in solution was measured with inductively coupled plasma atomic emission spectroscopy. The identity of corrosion products and their topography was determined with Raman spectroscopy and scanning electron microscopy, respectively. Nonirradiated reference samples were analyzed for comparison. The results show that radiation-induced corrosion of copper in anoxic water is significantly more effective on preoxidized copper compared to polished copper. The total amount of oxidized copper exceeds the amount expected solely from radiation chemistry of water by more than 3 orders of magnitude. To explain this discrepancy a mechanism is suggested where the hydroxyl radical (HO center dot) is the main radiolytic oxidative species driving the corrosion process. If the thermodynamic driving force would be large enough (such as for the hydroxyl radical or its precursor, H2O+), the oxide layer could conduct electrons from the metal to the hydroxyl radicals formed at oxide surfaces. The formation of an oxide layer will then result in an increased reactive surface area partly accounting for the observed discrepancy.

  • 13.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hosseinpour, Saman
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johnson, Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Radiation induced corrosion of copper for spent nuclear fuel storage2013In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 92, p. 80-86Article in journal (Refereed)
    Abstract [en]

    The long term safety of repositories for radioactive waste is one of the main concerns for countries utilizing nuclear power. The integrity of engineered and natural barriers in such repositories must be carefully evaluated in order to minimize the release of radionuclides to the biosphere. One of the most developed concepts of long term storage of spent nuclear fuel is the Swedish KBS-3 method. According to this method, the spent fuel will be sealed inside copper canisters surrounded by bentonite clay and placed 500 m down in stable bedrock. Despite the importance of the process of radiation induced corrosion of copper, relatively few studies have been reported. In this work the effect of the total gamma dose on radiation induced corrosion of copper in anoxic pure water has been studied experimentally. Copper samples submerged in water were exposed to a series of total doses using three different dose rates. Unirradiated samples were used as reference samples throughout. The copper surfaces were examined qualitatively using IRAS and XPS and quantitatively using cathodic reduction. The concentration of copper in solution after irradiation was measured using ICP-AES. The influence of aqueous radiation chemistry on the corrosion process was evaluated based on numerical simulations. The experiments show that the dissolution as well as the oxide layer thickness increase upon radiation. Interestingly, the evaluation using numerical simulations indicates that aqueous radiation chemistry is not the only process driving the corrosion of copper in these systems.

  • 14.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Hosseinpour, Saman
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Radiation Induced Corrosion of Copper in Anoxic Aqueous Solution2012In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 15, no 5, p. C5-C7Article in journal (Refereed)
    Abstract [en]

    The effect of gamma radiation on corrosion of copper under anoxic conditions in pure water has been studied experimentally. Copper samples submerged in water were exposed to dose rates of 0.37 or 0.77 kGy/h. Reference samples were used throughout. The copper surfaces have been examined using the techniques of SEM-EDS, IRAS, CR spectroscopy and AFM. Dissolution of copper was measured using ICP-OES. The results show that irradiated samples are more corroded than corresponding reference samples. This is also reflected by the increased concentration of copper in water after irradiation. Surface examination also reveals local corrosion features.

  • 15.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Hosseinpour, Saman
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Leygraf, Christopher
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Erratum to: Radiation Induced Corrosion of Copper in Anoxic Aqueous Solution (vol 15, pg C5, 2012)2012In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 15, no 6, p. S5-S5Article in journal (Refereed)
  • 16.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Radiation Induced Corrosion of Copper in Humid Air and Argon Atmospheres2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 4, p. C201-C206Article in journal (Refereed)
    Abstract [en]

    Corrosion of copper is a key-issue in the safety assessment of deep geological repositories for spent nuclear fuel utilizing copper coated canisters to isolate the spent nuclear fuel from the surrounding environment. Of particular interest is the radiation induced corrosion attributed to the inherent radioactivity of the spent nuclear fuel. In this work we have studied the radiation induced corrosion of copper in humid air and argon atmospheres. Polished copper cubes were gamma irradiated in the environments mentioned above at ambient temperature. Reference samples, not irradiated but otherwise treated under the exact same conditions as the irradiated samples, were used throughout the study. The oxide layers formed during radiation exposure were studied using cathodic reduction, infrared reflection/absorption spectroscopy, and the surfaces were examined using scanning electron microscopy. When possible, the concentration of copper in solution was measured using inductively coupled plasma atomic emission spectroscopy. The experimental results clearly show that radiation induced corrosion of copper in humid air as well as in humid argon is significantly more extensive than the corresponding process in anaerobic water. This is well in line with the recently proposed mechanism for radiation-induced corrosion of copper in anaerobic water. The very similar behavior of copper irradiated in humid air and in humid argon implies that the radiolytically formed HNO3 in the case of humid air has negligible impact on the radiation-induced corrosion compared to the radiolytically formed hydroxyl radical.

  • 17.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johnson, Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Radiation induced corrosion of copper in humid air and argonManuscript (preprint) (Other academic)
  • 18.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johnson, Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    The role of the oxide layerin radiation induced corrosion of copper in anoxic waterManuscript (preprint) (Other academic)
  • 19.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Yang, Miao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Gasparrini, Claudia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Kinetics and mechanisms of reactions between H2O2 and copper and copper oxides2015In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 44, no 36, p. 16045-16051Article in journal (Refereed)
    Abstract [en]

    One of the main challenges for the nuclear power industry today is the disposal of spent nuclear fuel. One of the most developed methods for its long term storage is the Swedish KBS-3 concept where the spent fuel is sealed inside copper canisters and placed 500 meters down in the bedrock. Gamma radiation will penetrate the canisters and be absorbed by groundwater thereby creating oxidative radiolysis products such as hydrogen peroxide (H2O2) and hydroxyl radicals (HO[radical dot]). Both H2O2 and HO[radical dot] are able to initiate corrosion of the copper canisters. In this work the kinetics and mechanism of reactions between the stable radiolysis product, H2O2, and copper and copper oxides were studied. Also the dissolution of copper into solution after reaction with H2O2 was monitored by ICP-OES. The experiments show that both H2O2 and HO[radical dot] are present in the systems with copper and copper oxides. Nevertheless, these species do not appear to influence the dissolution of copper to the same extent as observed in recent studies in irradiated systems. This strongly suggests that aqueous radiolysis can only account for a very minor part of the observed radiation induced corrosion of copper.

  • 20.
    Brinck, Tore
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Haeberlein, Markus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    A Computational Analysis of Substituent Effects on the O-H Bond Dissociation Energy in Phenols: Polar Versus Radical Effects1997In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 119, no 18, p. 4239-4244Article in journal (Refereed)
  • 21.
    Brinck, Tore
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Lee, Hau-Nan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Quantum Chemical Studies on the Thermochemistry of Alkyl and Peroxyl Radicals.1999In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 103, p. 7094-7104-Article in journal (Refereed)
  • 22.
    Bulone, Donatella
    et al.
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Dispenza, Clelia
    Dipartimento di Ingegneria, Università degli Studi di Palermo, Palermo, Italy.
    Ditta, Lorena A.
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Giacomazza, Daniela
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Antonietta Sabatino, Maria
    Dipartimento di Ingegneria, Università degli Studi di Palermo, Palermo, Italy.
    Lapasin, Romano
    University of Trieste, Trieste, Italy.
    Biagio, Pier L.San
    Institute of Biophysics, Consiglio Nazionale delle Ricerche, Palermo, Italy.
    Effect of gamma irradiation on HPC phase separation2023In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 122, no 3S1Article in journal (Refereed)
  • 23.
    Carlsson, Celice
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Fégeant, Benjamin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Svensson, Emelie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Wiklund, Love
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    On the Selectivity of Radical Scavengers Used To Probe Hydroxyl Radical Formation in Heterogeneous Systems2022In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 126, no 30, p. 12435-12440Article in journal (Refereed)
    Abstract [en]

    Tris and methanol have been used quite extensively as probes for surface-bound hydroxyl radicals in heterogeneous systems, such as TiO2 photocatalysis and catalytic decomposition of H2O2. Recent studies have indicated that the selectivity for surface-bound hydroxyl radicals is questionable and that the yield of the stable detectable product, formaldehyde, may be different for different reactive species. In this work, we have explored the selectivity as well as the formaldehyde yield of these two probes by experimentally studying formaldehyde formation in homogeneous (gamma radiolysis) and heterogeneous (TiO2 photocatalysis) systems, where hydroxyl radicals and Br-2.- can be formed. The latter is formed in the reaction between hydroxyl radicals and Br- at relatively high concentrations of Br-. The experiments clearly show that the formaldehyde yield is reduced by 85% when comparing hydroxyl radicals and Br2 & BULL;- in a homogeneous methanol system and increased by 50% when making the same comparison for the homogeneous Tris system. The increased yield is attributed to a change in the reaction mechanism as Br2 & BULL;- is mainly expected to produce a nitrogen-centered radical cation, while the hydroxyl radical mainly produces carbon-centered radicals. The radical cation appears to produce formaldehyde with a higher yield. In the photocatalysis system, the trends are similar but even more emphasized. The rationale for this is discussed, as well as the suitability of methanol and Tris as probes for surface-bound hydroxyl radicals in heterogeneous systems.

  • 24.
    Chen, Song
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Abdel-Magied, Ahmed Fawzy
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Fu, Le
    Uppsala Universitet, Department of Engineering Sciences.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Incorporation of strontium and europium in crystals of α-calcium isosaccharinate2019In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 364, p. 309-316Article in journal (Refereed)
    Abstract [en]

    The final repository for short-lived, low and intermediate level radioactive waste in Sweden is built to act as a passive repository. Already within a few years after closure water will penetrate the repository and conditions of high alkalinity (pH 10.5―13.5) and low temperature (< 7 °C) will prevail. The mobility of radionuclides in the repository is dependent on the radionuclides distribution between solid and liquid phases. In the present work the incorporation of strontium (II) and europium (III) in α-calcium isosaccharinate (ISA) under alkaline conditions (pH ~10) at 5 °C and 50 °C have been studied. The results show that strontium and europium are incorporated into α-Ca(ISA)2 when crystallized both at 5 °C and 50 °C. Europium is incorporated to a greater extent than strontium. The highest incorporation of europium and strontium at 5 °C rendered the phase compositions Ca0.986Eu0.014(ISA)2 (2.4% of Eu(ISA)3 by mass) and Ca0.98Sr0.02(ISA)2 (2.2% of Sr(ISA)2 by mass). XPS spectra show that both trivalent and divalent Eu coexist in the Eu incorporated samples. Strontium ions were found to retard the elongated growth of the Ca(ISA)2crystals. The incorporation of Sr2+ and Eu3+ into the solid phase of Ca(ISA)2 is expected to contribute to a decreased mobility of these ions in the repository.

  • 25. Cherkasov, A.
    et al.
    Jonsson, Mats.
    KTH, Superseded Departments (pre-2005), Chemistry.
    A new method for estimation of homolytic C-H bond dissociation enthalpies2000In: Journal of chemical information and computer sciences, ISSN 0095-2338, E-ISSN 1520-5142, Vol. 40, no 5, p. 1222-1226Article in journal (Refereed)
    Abstract [en]

    In this work we have quantitatively analyzed substituent effects on the homolytic bond dissociation enthalpy of 79 different compounds using a method based on discrete distance dependent atomic contributions to a molecular property. The resulting empirical relationship can be used to predict C-H bond dissociation enthalpies (within +/-10 kJ mol(-1)) for molecules where resonance contributions and captodative stabilization are insignificant. For species where captodative stabilization of the corresponding C-centered radical is possible, the method clearly overestimates the C-H bond dissociation enthalpy.

  • 26. Cherkasov, A. R.
    et al.
    Jonsson, Mats.
    KTH, Superseded Departments (pre-2005), Chemistry.
    Galkin, V. I.
    Cherkasov, R. A.
    Correlation analysis in the chemistry of free radicals2001In: Uspehi himii, ISSN 0042-1308, E-ISSN 1817-5651, Vol. 70, no 1, p. 3-27Article, review/survey (Refereed)
    Abstract [ru]

    Published data available by now on the use of correlation analysis in the free-radical chemistry are discussed systematically. The scales of <> sigma -constants of substituents proposed previously are analysed. It is shown that none of them is suitable as a general scale because almost in all cases, it is impossible to separate correctly the proper radical and polar contributions to the overall effect of substituents. A new approach to the quantitative estimation of the relationship between the structure and reactivity of molecules in free-radical processes is proposed and called r(-2)-analysis.

  • 27.
    Cherkasov, Artem
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Substituent Effects on Thermochemical Properties of C-, N-, O- and S-Centered Radicals. Physical Interpretation of Substituent Effects.1999In: Journal of chemical information and computer sciences, ISSN 0095-2338, E-ISSN 1520-5142, Vol. 39, p. 1057-1063Article in journal (Refereed)
  • 28.
    Cherkasov, Artem
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Substituent Effects on Thermochemical Properties of Free Radicals. New Substituent Scales for C-Centered Radicals1998In: Journal of chemical information and computer sciences, ISSN 0095-2338, E-ISSN 1520-5142, Vol. 38, no 6, p. 1151-1156Article in journal (Refereed)
  • 29.
    Cherkasov, Artem R
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Galkin, Vladimir
    University of Kazan, Russia.
    A Novel Approach to the Analysis of Substituent Effects. Quantitative Description of Ionization Energies and Gas Basicity of Amines.1999In: Journal of Molecular Graphics and Modelling, ISSN 1093-3263, E-ISSN 1873-4243, Vol. 17, no 15, p. 28-42Article in journal (Refereed)
  • 30.
    Chernyshev, Alexander
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Impact of organic cement additives on the mobility of radionuclides in a radioactive waste repository2017Conference paper (Refereed)
  • 31.
    Chernyshev, Alexander N.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Characterization and degradation of a polyaryl ether based superplasticizer for use in concrete barriers in deep geological repositories2018In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 95, p. 172-181Article in journal (Refereed)
    Abstract [en]

    Superplasticizers are important additives used in concrete barriers in geological waste repositories. Superplasticizers have been a major concern in the long-term assessments of safe geological disposal for radioactive waste since superplasticizers and their degradation products can act as complexing ligands and thereby increase the mobility of radionuclides. In this work a new type of superplasticizer, based on a polyaryl ether polymer, has been characterized. It was found that the superplasticizer combines the structural features of polycarboxylate ether based superplasticizers and sulfonated naphthalene-formaldehyde based superplasticizers and that it contains organophosphatecharged groups. A novel method for evaluating the rate of degradation of the superplasticizer under alkaline conditions was elaborated and the degradation products and rate constant of the process was determined. The results demonstrate that degradation occurs rapidly compared to the typical lifetime of a repository.

  • 32.
    Chernyshev, Alexander N.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Maier, Annika Carolin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Solubilization of Ni(II) and Eu(III) through complexation with a polyaryl ether based superplasticizer in alkaline media2021In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 263, article id 127686Article in journal (Refereed)
    Abstract [en]

    Solubilisation of Ni(II) and Eu(III) by complexation with a polyaryl ether based superplasticizer (PAE SP) in alkaline solutions was studied. The solubilization was investigated in two types of artificial cement pore waters simulating different stages of cement degradation at a pH of 12.4 and 13.3, respectively. The solubility of Ni(II) and Eu(III) increased as the concentration of superplasticizer was increased from 0.04 to 0.4 wt%. When the concentration of SP was increased from 0.4 to 4%, the solubility of Eu(III) and Ni(II) increased in the pore water with a pH of 12.4, while the concentrations decreased in the pore water with a pH of 13.3. This is explained by a more rapid degradation of the superplasticizer at higher pH leading to a release of phosphate groups and thereby precipitation of Eu(III) and Ni(II) as phosphates. Based on results of the solubilisation of Ni(II) and Eu(III) by model compounds (anisole and PEG 400) and 31P NMR spectroscopy it was confirmed that the complexation of the studied metals with the PAE polymer occurs via the phosphate group of the superplasticizer.

  • 33.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Thiol-ene coupling of 1,2-disubstituted alkene monomers: The kinetic effect of cis/trans-isomer structures2010In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 46, no 12, p. 2321-2332Article in journal (Refereed)
    Abstract [en]

    The free-radical induced reaction between a tri-functional thiol (2-ethyl-(hydroxymethyl)-1,3-propanediol trimercapto propionate) and two 1,2-disubstituted alkenes (methyl oleate and methyl elaidate) has been investigated under photochemical conditions. The photoreaction was monitored via time-resolved FUR, Raman and NMR spectroscopy to provide insights about the kinetics and efficiency in end-product formation. The information collected was subjected to numerical modelling using the GEPASI software using pre-established literature values for the rate coefficients in order to verify the proposed reaction scheme. The results confirm the thiol-ene reaction mechanism showing a very fast cis/trans-isomerization (<1.0 min) when compared with the total disappearance of unsaturations, indicating that the rate-limiting step controlling the reaction is the hydrogen transfer from the thiol involved in the formation of product. High thiol-ene conversions can be obtained at reasonable rates without major influence of side-reactions when performed in bulk indicating that this reaction is suitable for network forming purposes with mono-unsaturated fatty acid methyl esters derivatives. The kinetic and mechanistic information collected provides a basis for the design of new thiol-ene systems aiming at material and coating applications.

  • 34.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Thiol-ene coupling kinetics of D-limonene: a versatile 'non-click' free-radical reaction involving a natural terpene2013In: RSC Advances, E-ISSN 2046-2069, Vol. 3, no 27, p. 11021-11034Article in journal (Refereed)
    Abstract [en]

    The free-radical photoinduced thiol-ene reaction between D-limonene, as renewable diolefinic substrate, and two mono-/tri-functional thiols (iso-tridecyl 3-mercaptopropionate and trimethylolpropane tris(3-mercaptopropionate)), has been investigated kinetically to define a relationship between alkene structure and reactivity. Separate thiol-ene solutions of the appropriate thiol in d-chloroform, supplemented with 1.0 wt% of DMPA (Irgacure 651), were subjected to polychromatic UV-irradiation and the chemical changes monitored discontinuously via H-1 NMR spectroscopy to quantify double bond conversion. The kinetic concentration profiles were modeled analytically and simulated in the application software COPASI for parameter estimation and to verify if the experimental data explained a suggested mechanistic scheme. Empirical results demonstrate that the external vinylidene bond of limonene reacts about 6.5 times faster with thiol than the internal trisubstituted 1-methyl-cyclohexene unsaturation. The selectivity observed for the two unsaturations was successfully explained by means of a simplified steady-state equation derived from the sequential reaction mechanism accounting for propagation and chain-transfer elementary steps with estimated rate coefficients. Kinetic modeling results attribute the difference in selectivity partially to steric impediments controlling thiyl-radical insertion onto the double bonds and predominantly to differences in relative energy between the two tertiary insertion carbon radical intermediates. The rate-limiting step was identified as the third chain-transfer hydrogen-abstraction reaction promoted by the second insertion carbon radical intermediate. High thiol-ene conversions were obtained in a timely fashion without major influence of secondary reactions demonstrating the suitability of this reaction for network forming purposes. The mechanistic and kinetic information collected can be used as a quantitative predictive tool to assess the potential use of D-limonene in thiol-ene network forming systems involving multifunctional alkyl ester 3-mercaptopropionates.

  • 35.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Utilizing Thiol-Ene Coupling Kinetics in the Design of Renewable Thermosed Resins based on D-Limonene and Polyfunctional ThiolsManuscript (preprint) (Other academic)
  • 36.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Utilizing thiol-ene coupling kinetics in the design of renewable thermoset resins based on D-limonene and polyfunctional thiols2014In: RSC Advances, E-ISSN 2046-2069, Vol. 4, no 20, p. 10317-10329Article in journal (Refereed)
    Abstract [en]

    An extended model is developed to predict the free-radical thiol-ene reaction dynamics between D-limonene, as a renewable diolefin, and a monothiol compound (iso-tridecyl 3-mercaptopropionate) in bulk liquid conditions. Thermally and photo-initiated reactions of the two monomers showed favored thiol-ene coupling at the exo-isopropenyl alkene structure when reacted at 1 : 1 and 1 : 0.5 mole ratios. Experimental kinetic data obtained from the two stoichiometries were well reproduced numerically via the simulation software COPASI by introducing a multi-route mechanistic scheme with propagation-chain-transfer steps accounting for primary (mono-additions) and secondary (di-addition) modes of coupling. The differences in intrinsic double-bond reactivity enable synthesis of limonene-terminated resins (mono-versus poly-disperse) as multifunctional network precursors. Off-stoichiometry manipulations in the initial mole ratio, assisted by numerical simulations, offer a convenient approach to visualize the overall reaction system kinetics irrespective of temporal effects, thus being regarded as an important guiding tool for chemists aiming at designing thiol-ene systems based on limonene.

  • 37.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Mathevet, Jeanne-Marie
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Bringing D-limonene to the scene of bio-based thermoset coatings via free-radical thiol-ene chemistry: macromonomer synthesis, UV-curing and thermo-mechanical characterization2014In: Polymer Chemistry, ISSN 1759-9954, Vol. 5, no 9, p. 3245-3260Article in journal (Refereed)
    Abstract [en]

    The increasing pursuit for bio-based plastic materials led us to investigate the potential use of the monoterpene limonene in thermoset synthesis using the free-radical mediated thiol-ene reaction. The high efficiency of this reaction to prepare multifunctional ene-terminated resins, as intermediary macromolecular precursors, for thermosets synthesis was demonstrated under thermal and photoinitiated conditions. Although an excess of terpene favors formation of well-defined macromonomers in organic solution, the characteristic low-vapor pressure of limonene hinders its simple removal (or recycling) via evaporation after synthesis. Alteration to an initial thiol-ene stoichiometry of 1 : 0.5 enables production of high molecular weight resins in the form of 'hyperbranched oligomeric-like' structures having moderate polydispersity. UV-curing of these polyfunctional resins combined with equal mole compositions of multifunctional alkyl ester 3-mercapto propionates yields highly sticky, amorphous and flexible elastomers with different thermo-mechanical properties. These can be further modulated by varying the amount of unreacted thiol occluded within the networks working as a plasticizer. Introduction of a renewable cycloaliphatic structure into the materials offers a convenient way to enhance the glass-transition temperature and stiffness of traditional thiol-ene networks. The materials synthesized may be considered potentially useful as sealants and adhesives in a wide variety of applications including organic coatings. The versatility of UV-irradiation over thermal initiation makes this method particularly suitable for green industrial synthesis processes via thiol-ene chemistry using limonene and multifunctional thiols. The thiol-ene system evaluated herein serves as a model example for the sustainable incorporation of natural diolefinic monomers into semisynthetic thiol-ene networks exhibiting a range of thermo-mechanical properties.

  • 38.
    Claudino, Mauro
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    van der Meulen, Inge
    Eindhoven University of Technology, Laboratory of Polymer Chemistry, Eindhoven, The Netherlands.
    Trey, Stacy
    SP Trätek, SP Technical Research Institute of Sweden, Stockholm.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Heise, Andreas
    Eindhoven University of Technology, Laboratory of Polymer Chemistry, Eindhoven, The Netherlands.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Photoinduced thiol-ene cross-linking of globalide/ε-caprolactone copolymers: curing performance and resulting thermoset properties2012In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 50, no 1, p. 16-24Article in journal (Refereed)
    Abstract [en]

    The increasing demand for bioderived polymers led us to investigate the potential use of the macrolactone globalide in thermoset synthesis via the photoinduced thiolene reaction. A series of six lipase-catalyzed poly(globalide-caprolactone) copolyesters bearing internal main-chain unsaturations ranging from 10 to 50 and 100 mol % were successfully crosslinked in the melt with equal amounts of thiol groups from trimethylolpropane-trimercapto propionate affording fully transparent amorphous elastomeric materials with different thermal and viscoelastic properties. Three major conclusions can be drawn from this study: (i) high thiol-ene conversions (> 80%) were easily attained for all cases, while maintaining the cure behavior, and irrespective of functionality at reasonable reaction rates; (ii) parallel chain-growth homopropagation of the ene monomer is insignificant when compared with the main thiolene coupling route; and (iii) high ene-density copolymers result in much lower extracted sol fractions and high T(g) values as a result of a more dense and homogeneous crosslinked network. The thiol-ene system evaluated in this contribution serve as model example for the sustainable use of naturally occurring 1,2-disubstituted alkenes in making semisynthetic polymeric materials in high conversions with a range of properties.

  • 39.
    Coullerez, Geraldine
    et al.
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Carlmark, Anna
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Jonsson, Mats
    KTH, Superseded Departments (pre-2005), Chemistry.
    Understanding copper-based atom-transfer radical polymerization in aqueous media2004In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 108, no 35, p. 7129-7131Article in journal (Refereed)
    Abstract [en]

    This study investigates the mechanism of copper(I)-mediated living atom-transfer radical polymerization (ATRP) in aqueous media. It is shown that the ATRP apparent rate constant for polymerization of methoxycapped oligo(ethylene glycol) methacrylate (OEGMA) in water (k(P)(app)) at room temperature correlates with the redox potential (E-1/2) of the copper complexes. The results are discussed along with previously published results on the kinetics for bulk polymerization of methyl acrylate at 60 degreesC with the redox potentials measured in MeCN. The faster ATRP kinetics in water can mainly be attributed to a higher equilibrium concentration of propagating radicals [W] and to solvent effects on the rate of propagation k(p). It is shown that [R*] can be calculated from the redox properties of the alkyl halide and the copper complex. The values of [R*] in MeCN/bulk and in H2O were determined to be 8.2 x 10(-8) and 6.3 x 10(-5) M, respectively. The respective kp values are in good agreement with the literature values (3.6 x 10(3) M-1 s(-1) for OEGMA in water and 2.5 x 10(3) M-1 s(-1) for methyl acrylate in bulk).

  • 40.
    Coullerez, Geraldine
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Solvent effects on the redox properties of Cu complexes used as mediators in atom transfer radical polymerization2006In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 110, no 34, p. 10355-10360Article in journal (Refereed)
    Abstract [en]

    Solvent effects on the redox properties of six Cu(I) complexes used as mediators in atom transfer radical polymerization (ATRP) have been studied using cyclic voltammetry. The six ligands used were tris[2(dimethylamino) ethyl] amine, N-(n-propyl)-2-pyridylmethanimine, N, N, N', N', N'-pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyl-triethylenetetramine, 2,2'-bipyridine, and 1,4,8,11-tetraaza-1,4,8,11-tetramethylcyclotetradecan. The solvents used were DMSO, DMF, MeCN, MeOH, IP, and BuOH. Significant solvent effects were observed and quantitatively analyzed in terms of Kamlet-Taft relationships. The resulting Kamlet-Taft equations were found to successfully describe the solvent effects and could thus be used as tools for the design of ATRP in new solvents. The solvent sensitivity of the different ligands and the nature of the solvent effects are also discussed to some extent.

  • 41.
    Dahlgren, Björn
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Dispenza, Clelia
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Numerical Simulation of the Kinetics of Radical Decay in Single-Pulse High-Energy Electron-Irradiated Polymer Aqueous Solutions2019In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 123, no 24, p. 5043-5050Article in journal (Refereed)
    Abstract [en]

    A new method for the numerical simulation of the radiation chemistry of aqueous polymer solutions is introduced. The method makes use of a deterministic approach combining the conventional homogeneous radiation chemistry of water with the chemistry of polymer radicals and other macromolecular species. The method is applied on single-pulse irradiations of aqueous polymer solutions. The speciation of macromolecular species accounts for the variations in the number of alkyl radicals per chain, molecular weight, and number of internal loops (as a consequence of an intramolecular radical-radical combination). In the simulations, the initial polymer molecular weight, polymer concentration, and dose per pulse (function of pulse length and dose rate during the pulse) were systematically varied. In total, 54 different conditions were simulated. The results are well in line with the available experimental data for similar systems. At a low polymer concentration and a high dose per pulse, the kinetics of radical decay is quite complex for the competition between intra- and intermolecular radical-radical reactions, whereas at a low dose per pulse the kinetics is purely second-order. The simulations demonstrate the limitations of the polymer in scavenging all the radicals generated by water radiolysis when irradiated at a low polymer concentration and a high dose per pulse. They also show that the radical decay of lower-molecular-weight chains is faster and to a larger extent dominated by intermolecular radical-radical reactions, thus explaining the mechanism behind the experimentally observed narrowing of molecular weight distributions.

  • 42.
    Dahlgren, Björn
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Sabatino, Maria Antonietta
    Univ Palermo, Dipartimento Ingn, Viale Sci 6, I-90128 Palermo, Italy..
    Dispenza, Clelia
    Univ Palermo, Dipartimento Ingn, Viale Sci 6, I-90128 Palermo, Italy.;CNR, Ist Biofis IBF, Via U La Malfa 153, I-90146 Palermo, Italy..
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Numerical Simulations of Nanogel Synthesis Using Pulsed Electron Beam2020In: Macromolecular Theory and Simulations, ISSN 1022-1344, E-ISSN 1521-3919, Vol. 29, no 1, p. 1900046-, article id 1900046Article in journal (Refereed)
    Abstract [en]

    In this work, a new method for numerical simulation of the radiation chemistry of aqueous polymer solutions exposed to a sequence of electron pulses is presented. The numerical simulations are based on a deterministic approach encompassing the conventional homogeneous radiation chemistry of water as well as the chemistry of polymer radicals. The multitude of possible reactions in the macromolecular system is handled by allowing for a large number of macromolecular species. The speciation of macromolecular species is done to account for variations in molecular weight, number of alkyl radicals per chain, number of peroxyl radicals per chain, number of oxyl radicals per chain, and number of internal loops. As benchmarking, previously published results from a series of experiments on pulsed irradiation of aqueous poly(N-vinylpyrrolidone) (PVP) solutions are used. The numerical simulations clearly show that the pulsed nature of the radiation must be accounted for. The simulations qualitatively reproduce the experimentally observed impact of initial gas saturation (air and N2O) and polymer concentration on the molecular chain length upon irradiation. The formation of double bonds as a function of dose as well as the impact of effective dose rate on the final chain length are also qualitatively reproduced in the simulations.

  • 43.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Dunnill, Charles W.
    Bear, Joseph C.
    Firth, Steve
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Parkin, Ivan Paul
    Visible Light Photocatalytic Activity in AACVD-Prepared N-modified TiO2 Thin Films2014In: Chemical Vapor Deposition, ISSN 0948-1907, E-ISSN 1521-3862, Vol. 20, no 1-3, p. 91-97Article in journal (Refereed)
    Abstract [en]

    Nitrogen-modified TiO2 thin films are obtained, for the first time, from aerosol-assisted (AA)CVD-prepared samples via a post-treatment method involving immersion in liquid ammonia to achieve nitrogen-modified TiO2 and visible-light photo-activity. The resulting modified and unmodified TiO2 films are characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution (HR)TEM, energy dispersive X-ray (EDX) spectroscopy, selected area electron diffraction (SAED), UV-vis spectroscopy, and X-ray photoelectron spectroscopy (XPS). This shows that the films are approximate to 200nm thick and contain anisotropic crystals of anatase TiO2. XPS shows that the nitrogen is successfully added to the surface of the film interstitially at 0.7 at.-%, but is only present to a film depth of 50nm. The nitrogen doping causes a red shift in the absorption band and a band gap narrowing of approximate to 0.1eV. The surface-bound nitrogen results from the post-treatment method of doping where the films are soaked in liquid ammonia before annealing. The photocatalytic efficiencies of the films under visible light (>385nm) are evaluated by measuring formaldehyde formation from the probe molecule tris(hydroxymethyl)aminomethane (Tris). Hydrogen abstraction from Tris, obtained from, e.g., photocatalytically produced OH radicals, leads to formaldehyde formation which is then detected through a modified version of the Hantzsch reaction. The results show that the N-modified film possess remarkable photocatalytic properties with an apparent photochemical quantum yield of approximate to 8%. Nitrogen-modified TiO2 thin films are obtained from aerosol-assisted (AA)CVD-prepared samples via a post-treatment method of immersion in liquid ammonia and calcining at 500 degrees C. The films are characterized and shown to have visible light photocatalytic activity. Visible light photoactivity is shown by measuring formaldehyde formation from the probe molecule tris(hydroxymethyl)aminomethane.

  • 44.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Dunnill, Charles W.
    Österberg, Elin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Parkin, Ivan Paul
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Silver enhanced TiO2 thin films: photocatalytic characterization using aqueous solutions of tris(hydroxymethyl)aminomethane2014In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 43, no 1, p. 344-351Article in journal (Refereed)
    Abstract [en]

    The photocatalytic activity in aqueous solutions of TiO2 and Ag enhanced TiO2 sol-gel produced films was characterized using tris(hydroxymethyl)aminomethane (Tris) under black light (365 nm) and the observed differences in efficiency were further investigated by O-2 adsorption studies using the same probe. Hydrogen abstracting species, such as hydroxyl radicals formed upon photocatalysis, are able to abstract hydrogen from Tris. This reaction leads to the formation of formaldehyde which was detected and quantified through a modified version of the Hantzsch reaction. It was found that the Ag enhanced TiO2 film increased the apparent quantum yield from 7% to 12%, partly as a result of a Schottky barrier formation at the metal-semiconductor interface and partly as the sensitizing effect of Ag nanoparticles extends the visible light absorption, which through electron transfer processes enable an efficient charge separation in the TiO2 by attracting acceptor species more efficiently than pure TiO2. The O-2 adsorption studies in this paper showed that the Ag enhanced TiO2 film has a stronger adsorption affinity than pure TiO2 towards O-2, which make the reduction of O-2 more efficient with a subsequent enhanced electron-hole lifetime. It was also found that the Ag enhanced TiO2 film had a poorer adsorption affinity for Tris than the pure TiO2 film, which is a consequence of fewer available surface adsorption sites due to the Ag coverage at 64% which agrees well with the obtained adsorption equilibrium constants (K-LH(TiO2) = 615 M-1 and KLH(Ag-TiO2) = 320 M-1).

  • 45.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Effects of cellulose degradation products on the mobility of Eu(III) in repositories for low and intermediate level radioactive waste2017In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 340, p. 384-389Article in journal (Refereed)
    Abstract [en]

    The deep repository for low and intermediate level radioactive waste SFR in Sweden will contain large amounts of cellulosic waste materials contaminated with radionuclides. Over time the repository will be filled with water and alkaline conditions will prevail. In the present study degradation of cellulosic materials and the ability of cellulosic degradation products to solubilize and thereby mobilise Eu(III) under repository conditions has been investigated. Further, the possible immobilization of Eu(III) by sorption onto cement in the presence of degradation products has been investigated. The cellulosic material has been degraded under anaerobic and aerobic conditions in alkaline media (pH: 12.5) at ambient temperature. The degradation was followed by measuring the total organic carbon (TOC) content in the aqueous phase as a function of time. After 173 days of degradation the TOC content is highest in the anaerobic artificial cement pore water (1547 mg/L). The degradation products are capable of solubilising Eu(III) and the total europium concentration in the aqueous phase was 900 μmol/L after 498 h contact time under anaerobic conditions. Further it is shown that Eu(III) is adsorbed to the hydrated cement to a low extent (<9 μmol Eu/g of cement) in the presence of degradation products.

  • 46.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Comment on the use of phenols as probes for the kinetics of heterogeneous photocatalysis2014In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 158, p. 429-431Article in journal (Refereed)
  • 47.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Comment on the Use of Phenols as Probes for the Kinetics of Heterogeneous PhotocatalysisManuscript (preprint) (Other academic)
  • 48.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Effects of O2 and H2O2 on TiO2 photocatalytic efficiency quantified by formaldehyde formation from tris(hydroxymethyl)aminomethane2013In: Journal of AOTS. Advanced Oxidation Technologies, ISSN 1203-8407, Vol. 16, no 1, p. 16-22Article in journal (Refereed)
    Abstract [en]

    The impact of O2 and H2O2 on the efficiency of TiO2 photocatalysis has been studied in this work. Tris(hydroxymethyl)aminomethane (Tris) was used to probe the efficiency. Upon hydrogen abstraction by e.g. hydroxyl radicals from Tris, formaldehyde is formed. This product was detected and quantified using a modified version of the Hantzsch method. A significant increase in the formaldehyde production rate was observed upon addition of O2 or H2O2. It was also found that O2 and H2O2 are equally effective in scavenging the photo-excited electron, which is probably a result of their similar adsorption properties. A strong concentration dependence, independent of O2 or H2O2 content, was found at low Tris concentrations (&lt;100 mM). Adsorption studies of H2O 2 onto the TiO2 surface were performed in order to explore the rate controlling reactions. The results show that H2O 2, having a stronger adsorption affinity than Tris towards the photocatalytic surface, govern the kinetics, but only until a monolayer is built up.

  • 49.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Formation of H2O2 in TiO2 Photocatalysis of Oxygenated and Deoxygenated Aqueous Systems: A Probe for Photocatalytically Produced Hydroxyl Radicals2014In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 19, p. 10083-10087Article in journal (Refereed)
    Abstract [en]

    The formation of H2O2 in oxygenated and deoxygenated aqueous solutions using immobilized TiO2 illuminated by black light (365 nm) was studied to verify the presence of hydroxyl radicals in TiO2 photocatalysis. In oxygen containing systems, formation of H2O2 proceeds through reduction of molecular oxygen by conduction band electrons or by recombination of hydroxyl radicals. In oxygen free solutions recombination of hydroxyl radicals constitutes the only pathway to H2O2 formation. Detection of H2O2 in absence of oxygen therefore serves as an indicator for hydroxyl radical formation. The H2O2 concentration was determined using the Ghormley triiodide method. It was found that a significant amount of H2O2 was produced in the deoxygenated aqueous solutions supporting the hypothesis of hydroxyl radical production in photocatalysis. To further elucidate the origin of the H2O2, experiments using the radical scavenger tris(hydroxymethyL)aminomethane (Tris) were conducted. The results showed that the H2O2 concentration increased in the oxygenated system as Tris protects the H2O2 from decomposition by hydroxyl radicals. In the deoxygenated system, no H2O2 could be detected due to hydroxyl radical scavenging by Tris, which prevents H2O2 formation. The results presented support the hypothesis that the hydroxyl radical is the primary oxidant in aqueous TiO2 photocatalysis.

  • 50.
    Diesen, Veronica
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Tris(hydroxymethyl)aminomethane as a probe in heterogeneous TiO 2 photocatalysis2012In: Journal of AOTS. Advanced Oxidation Technologies, ISSN 1203-8407, Vol. 15, no 2, p. 392-398Article in journal (Refereed)
    Abstract [en]

    In this work we present a new route to probe the efficiency of aqueous TiO 2 photocatalysis using Tris(hydroxymethyl)aminomethane (Tris). Hydrogen abstracting species such as hydroxyl radicals react with Tris through hydrogen abstraction, which leads to the formation of formaldehyde. Formaldehyde was subsequently detected and quantified spectrophotometrically at 368 nm using a modified version of the Hantzsch reaction. The effect of Tris concentration on the photocatalytic production of formaldehyde was studied in the range 0.1-500 mM Tris. A strong concentration dependence was observed below 100 mM, which indicates that not all photo-produced (hydroxyl) radicals are scavenged at Tris concentrations below 100 mM. Therefore, in order to assess the maximum efficiency of the photocatalytic system, Tris concentrations above 100 mM are required. To evaluate the effect of O 2 on the formaldehyde yield in the reaction between Tris and the hydroxyl radical, a gamma radiolysis study was performed where Tris solutions saturated with O 2 and N 2, respectively, were irradiated in parallel and the yield of formaldehyde was compared. These results showed that O2 does not influence the formaldehyde yield.

12345 1 - 50 of 229
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