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  • 1. Amme, Marcus
    et al.
    Pehrman, Reijo
    Deutsch, Rudolf
    Roth, Olivia
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Combined effects of Fe(II) and oxidizing radiolysis products on UO2 and PuO2 dissolution in a system containing solid UO2 and PuO22012Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 430, nr 1-3, s. 1-5Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Radiation induced dissolution of (U, Gd)O-2 pellets in aqueous solution - A comparison to standard UO2 pellets2019Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 514, s. 216-223Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Radiation induced dissolution of (U, Gd)O2 pellets in aqueous solution: A comparison to standard UO2 pelletsManuskript (preprint) (Övrigt vetenskapligt)
    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, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Kumagai, Yuta
    Japan Atomic Energy Agency.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Impact of stoichiometry on the reactivity of UO2 towards radiolytic oxidantsManuskript (preprint) (Övrigt vetenskapligt)
  • 5.
    Barreiro Fidalgo, Alexandre
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Kumagai, Yuta
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    The role of surface-bound hydroxyl radicals in the reaction between H2O2 and UO22018Ingår i: Journal of coordination chemistry (Print), ISSN 0095-8972, E-ISSN 1029-0389, Vol. 71, nr 11-13, s. 1799-1807Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Sundin, Sara
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Effect of bentonite on radiation induced dissolution of UO2 in an aqueous system2014Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 447, nr 1-3, s. 73-76Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Coullerez, Geraldine
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Malmström, Eva E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Solvent Effects on ATRP of Oligo(ethylene glycol) Methacrylate. Exploring the Limits of Control2009Ingår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 42, nr 9, s. 3302-3308Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi (stängd 20110630).
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi (stängd 20110630).
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Investigation of iron complexes in ATRP: Indications of different iron species in normal and reverse ATRP2011Ingår i: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 346, nr 1-2, s. 20-28Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE).
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE).
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE).
    POLY 104-Predicting the level of control for ATRP systems2009Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 238Artikel i tidskrift (Övrigt vetenskapligt)
  • 10.
    Bergenudd, Helena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Predicting the Limit of Control in the ATRP Process: Results from Kinetic Simulations2011Ingår i: Macromolecular Theory and Simulations, ISSN 1022-1344, E-ISSN 1521-3919, Vol. 20, nr 9, s. 814-825Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Nyström, Daniel
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Heterogeneous iron(II)-chloride mediated radical polymerization of styrene2009Ingår i: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 306, nr 1-2, s. 69-76Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Role of the Oxide Layer in Radiation-Induced Corrosion of Copper in Anoxic Water2016Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, nr 21, s. 11450-11455Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Hosseinpour, Saman
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Johnson, Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Radiation induced corrosion of copper for spent nuclear fuel storage2013Ingår i: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 92, s. 80-86Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Hosseinpour, Saman
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Radiation Induced Corrosion of Copper in Anoxic Aqueous Solution2012Ingår i: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 15, nr 5, s. C5-C7Artikel i tidskrift (Refereegranskat)
    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, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johnson, C. Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Radiation Induced Corrosion of Copper in Humid Air and Argon Atmospheres2017Ingår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, nr 4, s. C201-C206Artikel i tidskrift (Refereegranskat)
    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.

  • 16.
    Björkbacka, Åsa
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johnson, Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Radiation induced corrosion of copper in humid air and argonManuskript (preprint) (Övrigt vetenskapligt)
  • 17.
    Björkbacka, Åsa
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johnson, Magnus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    The role of the oxide layerin radiation induced corrosion of copper in anoxic waterManuskript (preprint) (Övrigt vetenskapligt)
  • 18.
    Björkbacka, Åsa
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Yang, Miao
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Gasparrini, Claudia
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Kinetics and mechanisms of reactions between H2O2 and copper and copper oxides2015Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 44, nr 36, s. 16045-16051Artikel i tidskrift (Refereegranskat)
    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.

  • 19.
    Brinck, Tore
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi.
    Haeberlein, Markus
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    A Computational Analysis of Substituent Effects on the O-H Bond Dissociation Energy in Phenols: Polar Versus Radical Effects1997Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 119, nr 18, s. 4239-4244Artikel i tidskrift (Refereegranskat)
  • 20.
    Brinck, Tore
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi.
    Lee, Hau-Nan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Quantum Chemical Studies on the Thermochemistry of Alkyl and Peroxyl Radicals.1999Ingår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 103, s. 7094-7104-Artikel i tidskrift (Refereegranskat)
  • 21.
    Chen, Song
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Abdel-Magied, Ahmed F.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Fu, Le
    Uppsala Universitet, Department of Engineering Sciences.
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Incorporation of strontium and europium in crystals of α-calcium isosaccharinate2019Ingår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 364, s. 309-316Artikel i tidskrift (Refereegranskat)
    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.

  • 22. Cherkasov, A.
    et al.
    Jonsson, Mats.
    KTH, Tidigare Institutioner                               , Kemi.
    A new method for estimation of homolytic C-H bond dissociation enthalpies2000Ingår i: Journal of chemical information and computer sciences, ISSN 0095-2338, E-ISSN 1520-5142, Vol. 40, nr 5, s. 1222-1226Artikel i tidskrift (Refereegranskat)
    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.

  • 23. Cherkasov, A. R.
    et al.
    Jonsson, Mats.
    KTH, Tidigare Institutioner                               , Kemi.
    Galkin, V. I.
    Cherkasov, R. A.
    Correlation analysis in the chemistry of free radicals2001Ingår i: Uspehi himii, ISSN 0042-1308, E-ISSN 1817-5651, Vol. 70, nr 1, s. 3-27Artikel, forskningsöversikt (Refereegranskat)
    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.

  • 24.
    Cherkasov, Artem
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Substituent Effects on Thermochemical Properties of C-, N-, O- and S-Centered Radicals. Physical Interpretation of Substituent Effects.1999Ingår i: Journal of chemical information and computer sciences, ISSN 0095-2338, E-ISSN 1520-5142, Vol. 39, s. 1057-1063Artikel i tidskrift (Refereegranskat)
  • 25.
    Cherkasov, Artem
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Substituent Effects on Thermochemical Properties of Free Radicals. New Substituent Scales for C-Centered Radicals1998Ingår i: Journal of chemical information and computer sciences, ISSN 0095-2338, E-ISSN 1520-5142, Vol. 38, nr 6, s. 1151-1156Artikel i tidskrift (Refereegranskat)
  • 26.
    Cherkasov, Artem R
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    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.1999Ingår i: Journal of Molecular Graphics and Modelling, ISSN 1093-3263, E-ISSN 1873-4243, Vol. 17, nr 15, s. 28-42Artikel i tidskrift (Refereegranskat)
  • 27.
    Chernyshev, Alexander
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Impact of organic cement additives on the mobility of radionuclides in a radioactive waste repository2017Konferensbidrag (Refereegranskat)
  • 28.
    Chernyshev, Alexander N.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Characterization and degradation of a polyaryl ether based superplasticizer for use in concrete barriers in deep geological repositories2018Ingår i: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 95, s. 172-181Artikel i tidskrift (Refereegranskat)
    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.

  • 29.
    Claudino, Mauro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Johansson, Mats K. G.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Thiol-ene coupling of 1,2-disubstituted alkene monomers: The kinetic effect of cis/trans-isomer structures2010Ingår i: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 46, nr 12, s. 2321-2332Artikel i tidskrift (Refereegranskat)
    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.

  • 30.
    Claudino, Mauro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johansson, Mats
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Thiol-ene coupling kinetics of D-limonene: a versatile 'non-click' free-radical reaction involving a natural terpene2013Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, nr 27, s. 11021-11034Artikel i tidskrift (Refereegranskat)
    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.

  • 31.
    Claudino, Mauro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johansson, Mats
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Utilizing Thiol-Ene Coupling Kinetics in the Design of Renewable Thermosed Resins based on D-Limonene and Polyfunctional ThiolsManuskript (preprint) (Övrigt vetenskapligt)
  • 32.
    Claudino, Mauro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johansson, Mats
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Utilizing thiol-ene coupling kinetics in the design of renewable thermoset resins based on D-limonene and polyfunctional thiols2014Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, nr 20, s. 10317-10329Artikel i tidskrift (Refereegranskat)
    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.

  • 33.
    Claudino, Mauro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Mathevet, Jeanne-Marie
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Johansson, Mats K. G.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Bringing D-limonene to the scene of bio-based thermoset coatings via free-radical thiol-ene chemistry: macromonomer synthesis, UV-curing and thermo-mechanical characterization2014Ingår i: Polymer Chemistry, ISSN 1759-9954, Vol. 5, nr 9, s. 3245-3260Artikel i tidskrift (Refereegranskat)
    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.

  • 34.
    Claudino, Mauro
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    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, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Heise, Andreas
    Eindhoven University of Technology, Laboratory of Polymer Chemistry, Eindhoven, The Netherlands.
    Johansson, Mats K. G.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Photoinduced thiol-ene cross-linking of globalide/ε-caprolactone copolymers: curing performance and resulting thermoset properties2012Ingår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 50, nr 1, s. 16-24Artikel i tidskrift (Refereegranskat)
    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.

  • 35.
    Coullerez, Geraldine
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Carlmark, Anna
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Malmström, Eva
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Jonsson, Mats
    KTH, Tidigare Institutioner, Kemi.
    Understanding copper-based atom-transfer radical polymerization in aqueous media2004Ingår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 108, nr 35, s. 7129-7131Artikel i tidskrift (Refereegranskat)
    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).

  • 36.
    Coullerez, Geraldine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Kärnkemi.
    Solvent effects on the redox properties of Cu complexes used as mediators in atom transfer radical polymerization2006Ingår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 110, nr 34, s. 10355-10360Artikel i tidskrift (Refereegranskat)
    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.

  • 37.
    Dahlgren, Björn
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Dispenza, Clelia
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Numerical Simulation of the Kinetics of Radical Decay in Single-Pulse High-Energy Electron-Irradiated Polymer Aqueous Solutions2019Ingår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 123, nr 24, s. 5043-5050Artikel i tidskrift (Refereegranskat)
    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.

  • 38.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Dunnill, Charles W.
    Bear, Joseph C.
    Firth, Steve
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Parkin, Ivan Paul
    Visible Light Photocatalytic Activity in AACVD-Prepared N-modified TiO2 Thin Films2014Ingår i: Chemical Vapor Deposition, ISSN 0948-1907, E-ISSN 1521-3862, Vol. 20, nr 1-3, s. 91-97Artikel i tidskrift (Refereegranskat)
    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.

  • 39.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Dunnill, Charles W.
    Österberg, Elin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Parkin, Ivan Paul
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Silver enhanced TiO2 thin films: photocatalytic characterization using aqueous solutions of tris(hydroxymethyl)aminomethane2014Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 43, nr 1, s. 344-351Artikel i tidskrift (Refereegranskat)
    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).

  • 40.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Effects of cellulose degradation products on the mobility of Eu(III) in repositories for low and intermediate level radioactive waste2017Ingår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 340, s. 384-389Artikel i tidskrift (Refereegranskat)
    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.

  • 41.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Comment on the Use of Phenols as Probes for the Kinetics of Heterogeneous PhotocatalysisManuskript (preprint) (Övrigt vetenskapligt)
  • 42.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Comment on the use of phenols as probes for the kinetics of heterogeneous photocatalysis2014Ingår i: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 158, s. 429-431Artikel i tidskrift (Refereegranskat)
  • 43.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Effects of O2 and H2O2 on TiO2 photocatalytic efficiency quantified by formaldehyde formation from tris(hydroxymethyl)aminomethane2013Ingår i: Journal of AOTS. Advanced Oxidation Technologies, ISSN 1203-8407, Vol. 16, nr 1, s. 16-22Artikel i tidskrift (Refereegranskat)
    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.

  • 44.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Formation of H2O2 in TiO2 Photocatalysis of Oxygenated and Deoxygenated Aqueous Systems: A Probe for Photocatalytically Produced Hydroxyl Radicals2014Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, nr 19, s. 10083-10087Artikel i tidskrift (Refereegranskat)
    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.

  • 45.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Tris(hydroxymethyl)aminomethane as a probe in heterogeneous TiO 2 photocatalysis2012Ingår i: Journal of AOTS. Advanced Oxidation Technologies, ISSN 1203-8407, Vol. 15, nr 2, s. 392-398Artikel i tidskrift (Refereegranskat)
    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.

  • 46.
    Diesen, Veronica
    et al.
    Materials Chemistry Research Centre, Department of Chemistry University College London.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Parkin, Ivan Paul
    Improved Texturing and Photocatalytic Efficiency in TiO2 Films Grown Using Aerosol-Assisted CVD and Atmospheric Pressure CVD2013Ingår i: Chemical Vapor Deposition, ISSN 0948-1907, E-ISSN 1521-3862, Vol. 19, nr 10-12, s. 355-362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Four different TiO2 films are formed on glass at 500 degrees C by aerosol-assisted (AA)CVD, atmospheric pressure (AP)CVD, AACVD followed by APCVD, and APCVD followed by AACVD. The APCVD films are formed from reaction of TiCl4(g) whilst the AACVD films are made by decomposing Ti[OCH(CH3)(2)](4) contained in an aerosol. The film composition is studied using X-ray photoelectron spectroscopy (XPS) to ascertain the purity of the films, and no Cl traces can be found on any of the surfaces. The use of different combinations of CVD gives rise to significant changes in microstructure and preferred orientations. X-ray diffraction (XRD) patterns and Raman spectroscopy (RS) confirm that TiO2 in the anatase form is the dominant phase on all samples. All films show superhydrophilicity after 50min of black-light irradiation. The photocatalytic efficiencies of the films are assessed qualitatively by an ink test based on Resazurin, and quantitatively studied by measuring formaldehyde formation from tris(hydroxymethyl)aminomethane (Tris). Both methods show that the AACVD film and the film seeded by APCVD are the most photocatalytically efficient ones, both having an apparent quantum yield (AQY) of around 4.2%, while the APCVD film and the film seeded by AACVD have an AQY of 0.8% and 1.5%, respectively. The changes in photocatalytic activity are explained in part by changes in film microstructure and the accessible surface area.

  • 47.
    Dispenza, C.
    et al.
    Univ Palermo, Dipartimento Ingn Chim, Gest, Informat,Meccan, Viale Sci,Edificio 6, I-90128 Palermo, Italy.;Royal Inst Technol KTH, Sch Chem Sci & Engn, S-10044 Stockholm, Sweden..
    Spadaro, G.
    Univ Palermo, Dipartimento Ingn Chim, Gest, Informat,Meccan, Viale Sci,Edificio 6, I-90128 Palermo, Italy..
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Erratum to: Radiation Engineering of Multifunctional Nanogels2016Ingår i: TOPICS IN CURRENT CHEMISTRY, ISSN 2365-0869, Vol. 374, nr 5, artikel-id 72Artikel i tidskrift (Refereegranskat)
  • 48. Dispenza, C.
    et al.
    Spadaro, G.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Radiation Engineering of Multifunctional Nanogels2016Ingår i: Topics in Current Chemistry, ISSN 2365-0869, Vol. 374, nr 5, artikel-id 69Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Nanogels combine the favourable properties of hydrogels with those of colloids. They can be soft and conformable, stimuli-responsive and highly permeable, and can expose a large surface with functional groups for conjugation to small and large molecules, and even macromolecules. They are among the very few systems that can be generated and used as aqueous dispersions. Nanogels are emerging materials for targeted drug delivery and bio-imaging, but they have also shown potential for water purification and in catalysis. The possibility of manufacturing nanogels with a simple process and at relatively low cost is a key criterion for their continued development and successful application. This paper highlights the most important structural features of nanogels related to their distinctive properties, and briefly presents the most common manufacturing strategies. It then focuses on synthetic approaches that are based on the irradiation of dilute aqueous polymer solutions using high-energy photons or electron beams. The reactions constituting the basis for nanogel formation and the approaches for controlling particle size and functionality are discussed in the context of a qualitative analysis of the kinetics of the various reactions.

  • 49. Dispenza, Clelia
    et al.
    Grimaldi, Natascia
    Sabatino, Maria Antonietta
    Soroka, Inna L.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Radiation-Engineered Functional Nanoparticles in Aqueous Systems2015Ingår i: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 15, nr 5, s. 3445-3467Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Controlled synthesis of nanoscalar and nanostructured materials enables the development of novel functional materials with fine-tuned optical, mechanical, electronic, magnetic, conductive and catalytic properties that are of use in numerous applications. These materials have also found their potential use in medicine as vehicles for drug delivery, in diagnostics or in combinations thereof. In principle, nanoparticles can be divided into two broad categories, organic and inorganic nanoparticles. For both types of nanoparticles there are numerous possible synthetic routes. Considering the large difference in nature of these materials and the elementary reactions involved in the synthetic routes, most manufacturing techniques are complex and only suitable for one type of particle. Interestingly, radiation chemistry, i.e., the use of ionizing radiation from radioisotopes and accelerators to induce nanomaterials or chemical changes in materials, has proven to be a versatile tool for controlled manufacturing of both organic and inorganic nanoparticles. The advantages of using radiation chemistry for this purpose are many, such as low energy consumption, minimal use of potentially harmful chemicals and simple production schemes. For medical applications one more advantage is that the material can be sterile as manufactured. Radiation-induced synthesis can be carried out in aqueous systems, which minimizes the use of organic solvents and the need for separation and purification of the final product. The radiation chemistry of water is well known, as are the various ways of fine-tuning the reactivity of the system towards a desired target by adding different solutes. This, in combination with the controllable and adjustable irradiation process parameters, makes the technique superior to most other chemical methods. In this review, we discuss the fundamentals of radiation chemistry and radiation-induced synthesis of nanoparticles in aqueous solutions. The impact of dose and dose rate as well as of controlled addition of various solutes on the final particle composition, size and size distribution are described in detail and discussed in terms of reaction mechanism and kinetics.

  • 50.
    Dispenza, Clelia
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. Università Degli Studi di Palermo, Italy.
    Sabatino, M. A.
    Grimaldi, N.
    Mangione, M. R.
    Walo, M.
    Murugan, Eagambaram
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    On the origin of functionalization in one-pot radiation synthesis of nanogels from aqueous polymer solutions2016Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, nr 4, s. 2582-2591Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Radiation-engineered poly(N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v. administration of therapeutics and contrast agents for bioimaging. The manufacturing process is fast and effective, it grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio) conjugation, are also formed in a dose-dependent fashion. In this paper, by means of both numerical simulations and experiments, the origin of nanogel size control and functionalization is investigated. This understanding offers a new dimension for the design and production of radiation-sculptured multifunctional nanocarriers from aqueous solutions of polymers.

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