La présente étude a démontré l'effet de certains additifs sur les propriétés de vieillissement des composites élastomères. Dans les travaux actuels des colorants, des pigments à hautes performances et des liquides ioniques conducteurs ont été utilisés comme additifs pour obtenir des composites à base d'élastomère, caractérisés par une meilleure résistance aux intempéries et au vieillissement et avec de bonnes propriétés mécaniques. Les propriétés mécaniques des composites d'éthylène – norbornène, ont confirmé que les colorants avec des substituants fortement donneurs d'électrons, apportent une meilleure et plus efficace protection contre le vieillissement dans le spectre solaire, que la plupart des stabilisants commerciaux utilisés dans la technologie des polymères. La partie suivante de la thèse a porté sur l'impact des liquides ioniques hydrophile et hydrophobe à base d'imidazolium dans les caoutchoucs butadiène-acrylonitrile. L'influence de la nature de l'anion (thiocyanate SCN, bis (trifluorométhylsulfonyl)imide TFSI) et de la longueur de la chaîne alkyle du cation (éthyl, hexyl) des liquides ioniques à base d'imidazolium sur la cinétique de durcissement, sur les propriétés mécanique et morphologique, sur la conductivité ionique et sur la tenue aux intempéries des composites en caoutchouc nitrile a été étudiée. Il a été constaté que l'addition de liquides ioniques hydrophobes à base d'imidazolium – TFSI – en quantité de 2,5 à 5 phr, améliore le plus efficacement les propriétés mécaniques ainsi que la conductivité ionique des matériaux composites NBR et présente un effet positif sur la matrice de caoutchouc pendant l'exposition à l'extérieur / The present study demonstrated the effect of some additives on aging properties of elastomer composites. In the current work solvent dyes, high performance pigments and conductive ionic liquids were employed as additives to obtain elastomer composites, characterized by enhanced weathering aging resistance and good mechanical properties. In the first part of the investigation, selected solvent dyes mainly with anthraquinone chromophores and high performance pigments, which exhibited high light and temperature resistance, were applied in ethylene-norbornene cyclic olefin and acrylonitrile butadiene rubber and then subjected to aging process. The mechanical properties as well as surface analysis of ethylene-norbornene composites, confirmed that solvent dyes, provided better efficient protection against aging in full sun spectrum, than most investigated commercial stabilizers used in polymer technology. Next part of thesis was focused on impact of hydrophilic and hydrophobic imidazolium ionic liquids on acrylonitrile-butadiene rubber. The influence of (thiocyanate, SCN;bis(trifluoromethylsulfonyl)imide, TFSI) anion type and the length of alkyl chain (from ethyl to hexyl) for the cations of imidazolium ionic liquids on the curing kinetic, mechanical, morphological, ionic conductivity and weathering properties of nitrile rubber composites was investigated. It was found, that the addition of hydrophobic TFSI-based imidazolium ILs in quantity 2.5-5 phr, the most effectively improved, mechanical properties and ionic conductivity of the NBR composites and exhibit some positive effect on rubber matrix during outdoor exposure

Dizertační práce je zaměřena na studium elektrických a dielektrických vlastností iontových kapalin. Iontové kapaliny mohou nacházet uplatnění v široké škále aplikací, především pak v elektrotechnice. Teoretická část se věnuje popisu základních vlastností iontových kapalin a možností jejich uplatnění v kondenzátorech a elektrochemických senzorech plynů. Experimentální část se věnuje použitým metodám charakterizace vlastností iontových kapalin, jsou zde popsány teoretické poznatky o dielektrické spektroskopii včetně metod stanovení fyzikálních vlastností a vyhodnocení experimentálních dat. Experimentální část je rozdělena na dvě základní části. První se věnuje studiu iontových kapalin pro použití jako elektrolytu v kondenzátorech, druhá část se věnuje studiu vlastností připravených experimentálních senzorů na NO2, zejména vlivem vlastností iontových kapalin na sledované parametry senzoru.

No description available.

Ionic liquids (ILs) are nowadays a large and widely explored class of ionic compounds that melt below 100 °C. Due to their attractive properties, ILs are now of growing interests in a variety of inorganic materials preparation. However, most studies have put much focus on the description of new synthetic strategies. The chemical reactivity of ILs in the reactions is often neglected. In this dissertation, a series of metal chalcogenides were synthesized using the decompositions of ILs. The role or chemical reactivity of ILs in the reactions was demonstrated in detail. The hierarchical desert-rose-like SrTiO3 particles have been successfully prepared based on an ethylene glycol (EG) mediated one-pot IL-assisted solvothermal synthetic route. The used basic ionic liquid tetrabutylammonium hydroxide (TBAH) serves as an alkaline source and can also replace EG as the sole solvent to synthesize polyhedral SrTiO3, showing “all-in-one” solvent and reactant. A series of metal sulfides, such as Sb2S3, Bi2S3, PbS, CuS, Ag2S, ZnS, and CdS have been obtained from a choline chloride/thioacetamide based deep eutectic solvent (DES, an IL analog solvent) by a simple and general synthetic method. The reaction mainly proceeds in two steps: i) the dispersion of metal salts in the DES and the formation of a metal-DES complex, and ii) the decomposition of the metal-DES complex and formation of the final products. In addition, the chemical reactivity of phosphonium based ILs with selenium and tellurium at above 220 °C was systematically investigated by a series of dissolution experiments, tracking the solute selenium and tellurium species by nuclear magnetic resonance (NMR). NMR results clearly indicate some common decomposition mechanisms for quaternary phosphonium ILs at a relatively high temperature in the presence of selenium or tellurium. The decomposition of the quaternary phosphonium cations should proceed by an elimination of one alkyl substituent via an SN2 reaction, forming the respective trialkylphosphane selenides or tellurides in the presence of selenium or tellurium, which is then responsible for the genuine dissolution of selenium or tellurium. However, in the case of tellurium, the dissolution behavior is much more complicated compared to that of selenium. The coupling of P and Te which indicates a P–Te bond formation is only observed in the NMR spectra when a sufficient amount of tellurium (e.g. Te : IL = 1 : 1) is provided. The existence of a parallel-competitive IL decomposition route besides the SN2 reaction is regarded as the side reaction for the dissolution of tellurium. This may at least partially explain the relatively lower solubility of tellurium in phosphonium based ILs compared to that of selenium.

Ett nytt sätt att aktivera cellulosa för kemisk modifiering med hjälp av en miljövänlig process har utvecklats innan starten av detta projekt. Två versionen av den nyskapade betain-baserade jonvätskan, BBIL har syntetiserats, en som använder mesylat som motjon, M-BBIL och en som använder acetat, A-BBIL. Innan yt-initierad Ringöppningspolymerisation (SI-ROP) kan göras på den aktiverade cellulosan är det av intresse att undersöka hur jonvätskorna kommer påverka polymerisationen.  Det katalytiska beteendet hos både M-BBIL och A-BBIL testades på två olika polymerisationsreaktioner. Först testades ROP av ε-CL. Resultaten visade att ingen av jonvätskorna kunde visa någon samkatalytisk förmåga när de användes tillsammans med katalysatorerna MSA och DPP. När A-BBIL användes på egen hand ansågs den vara ineffektiv då termisk nedbrytning hämmade polymerisation vid temperaturer över 85oC. M-BBIL kunde dock uppnå bra kinetik då den användes vid 160oC. Den andra reaktionen som testades var coROP av ftalsyraanhydrid-cyklohexenoxid (PACHO) samt ftalsyraanhydrid-limonenoxid (PALO). Båda sampolymerisationer lyckades polymerisera med hjälp av M-BBIL, med endast mindre mängder av homopolymerisation av epoxiden under rätt förhållanden. Reaktionen visade sig dock vara mycket känslig för vatten och mer arbete krävs för att optimera reaktionen och nå högre molekylvikter. Tester för att försöka ympa PACHO polymerer på cellulosa som först hade aktiverats och sedan modifierats för att ha ftalsyraanhydrid på ytan visade sig också vara mycket känsliga för vatten. En lyckad ympning kunde dock uppnås genom att utföra reaktionen i ett delvist torkat, hydrofobt lösningsmedel. / A new way of activating cellulose for chemical modification using green processing conditions has been developed before the start of this thesis. Two versions of the novel betaine-based ionic liquid, BBIL has been synthesised, one using mesylate as a counter-ion, M-BBIL and one using acetate, A-BBIL. Before surface initiated-Ring Opening Polymerisation (SI-ROP) onto the activated cellulose can proceed, it is of interest to investigate the effects that the ionic liquids will have on the polymerization behaviour. The catalytic behaviour of both M-BBIL and A-BBIL were tested on two different polymerisation reactions. Firstly, ROP of ε-CL was tested. The results showed that neither ionic liquid could show any co-catalytic behaviour when used in combination with the catalysts MSA and DPP. When used on their own, A-BBIL was concluded to be ineffective since thermal degradation inhibited polymerisation at temperatures above 85oC. M-BBIL could however achieve good kinetics when used at 160oC. The second reaction that was tested was the coROP of phthahlic anhydridecyclohexene oxide (PACHO) and phthalic anhydride-limonene oxide (PALO). Both copolymerisations could successfully be polymerised using M-BBIL, with only minor amounts of homopolymerisation of the epoxide if the right conditions were used. The reactions were however shown to be highly sensitive to water and more optimization is needed to reach higher molecular weights. Tests of trying to graft the PACHO polymers onto cellulose that had first been activated and then modified with phthalic anhydride moieties was also shown to be highly sensitive to water. Successful grafting could however be achieved by performing reaction in partially dried hydrophobic solvents.

No description available.

The interfacial structuring of three non-halogenated ionic liquids was examined at the air-liquid interface for both dry and humid condition by analysis of X-ray reflectometry data using a slab model approach. The aim was to investigate the effect of humidity on the air-liquid interface. Pure ionic liquids as well as solutions of 5% w/w and 20% w/w in propylene carbonate were examined. Three different cations were used, a phosphonium cation ([P6,6,6,14]+) and two dialkylimidazolium cations ([C6C1Im]+ and [C10C1Im]+). The anion was bis(mandelato)borate ([BMB]-), which is a non-commercial anion that has been shown to exhibit excellent tribological properties. The results reveal that the presence of ambient water has an impact on the interfacial structure and the layering of all pure ionic liquids, as well as most cases of ionic liquid solutions. Exposure to humidity had the largest response in the case of all pure and diluted solutions of [C6C1Im][BMB], for which a more pronounced layering was observed. The [P6,6,6,14][BMB] solutions did not exhibit any significant changes when exposed to ambient water, with the 20% w/w solution proving to be the most stable. / Gränsskiktsstrukturen hos tre olika icke-halogenerade jonvätskor undersöktes vid luft-vätskegränsskiktet för både torra och fuktiga förhållanden genom analys av data från en röntgen reflektometer med en “slab model approach”. Målet var att undersöka effekten av luftfuktighet på luft-vätskagränsskiktet. Rena jonvätskor såväl som lösningar av 5 och 20 vikt-% utspädda i propylenkarbonat undersöktes. Tre olika katjoner användes, en fosforkatjon ([P6,6,6,14]+) samt två dialkylimidazoliumkatjoner ([C6C1Im]+ och [C10C1Im]+). Anjonen var bis(madelato)borat ([BMB]-), vilket är en icke-kommersiell anjon som har visat bra tribologiska egenskaper. Resultatet visar att närvaron av omgivande vatten har en påverkan på gränsskiktsstrukturen samt skiktning hos alla rena jonvätskor och de flesta utspädda lösningar. Exponering för fuktighet hade den största inverkan på alla rena och utspädda lösningar av [C6C1Im][BMB], för vilka en mer distinkt skiktning kunde observeras. [P6,6,6,14][BMB] lösningar uppvisade inga signifikanta ändringar vid exponering till fuktig luft, där den lösning med 20 vikt-% visade sig vara mest stabil.

As the UN summit in September 2015 addressed with the Sustainable Development Goals (SDG), our planet faces great challenges.[1] Not only since then has the role of synthetic materials chemistry been discussed in this context.[2–16] This not only concerns the development of new materials with outstanding properties such as catalysts, materials for energy conversion, and cost-efficient energy converting and storage materials, but also a reduction of the energy consumption of established functional material syntheses. Therefore, new approaches addressing the three main categories to promote the potential for energy and resource efficiency have been proposed: lowering the temperature of the synthetic processes, improving the yield and purity of the materials, and reducing the amount of waste materials. In this context a number of low-temperature processes have been established, in which mainly solvents, i.e. amines and alcohols, are used in combination with previously synthesised precursors as the solubility of the starting materials limits their usability and most elements are not soluble in these solvents. Novel solvents like ionic liquids (ILs) showcase growing interest as they are considered particularly resource-efficient.[17,18] ILs are defined as liquids that are comprised entirely of ions, with melting points below 100 °C. Continuing on from the reported work in this field, this thesis focuses on investigating the ability of ILs in the syntheses for known chalcogenides at lower temperatures and the synthesis of new materials. The main focus lies on conversions with high atom economy, especially by starting from the elements and completely recycling the IL afterwards, and mechanistic studies elucidating the intermediate dissolved species. Furthermore, as imidazolium based ILs, and their derived LEWIS-acidic ILs [BMIm]Cl/nAlCl3 mixtures, have proven to be good crystallisation media in inorganic syntheses, and the class of mostly room-temperature liquid ILs (RTILs) based on phosphonium cations [P66614]Cl showcased the ability to dissolve red phosphorous, Pred, and the heavier chalcogens S, Se, and Te, this work mainly focuses on these two IL systems. This was also chosen as an in-depth understanding of the activation and resource-efficient synthesis of these chalcogenides has still not been established. As they are RTILs, they also made the characterisation of the reactive and dissolved species by liquid state NMR, Raman, UV/Vis spectroscopy and electrochemical characterisation possible. This expands the knowledge of which main group elements and ore-like starting materials can be used in ionothermal synthesis. As a starting point the thermoelectrically interesting materials class of tellurides is addressed. The under normal conditions hard to dissolve element tellurium readily dissolves in phosphonium ILs with the cations [P66614]+ and [P4444]+. In ILs with carboxylate anions a deep purple hue of the IL already occurred by dissolving tellurium at temperatures of 60 °C. Investigations on the solutions in the acetate ILs revealed the formation of tellurium anions (Ten)2– with chain lengths up to at least n = 5, which are in a dynamic equilibrium with each other. Since external influences could be excluded and no evidence of an IL reaction was found, disproportionation of the tellurium is the only possible dissolution mechanism. However, the spectroscopic detection of tellurium cations in these solutions is difficult, but the coexistence of tellurium cations, such as (Te4)2+ and (Te6)4+, and tellurium anions could be proven by cyclic voltammetry and electrodeposition experiments. DFT calculations indicate that electrostatic interactions with the ions of the ILs are sufficient in stabilizing both types of tellurium ions in solution.[19] In contrast, the acetate ILs show insufficient conversion in reactions of coin metals (Cu, Ag, Au) with tellurium to the corresponding tellurides, especially at low temperatures, however the chloride ILs successfully synthesise Cu2–xTe, CuTe, AuTe2 and Ag2Te. As the synthesis of the tellurides in neat ILs at temperatures down to 60 °C was only sufficient for the system Ag-Te, with a full conversion of the elements to Ag2Te, this was chosen as a model system for further investigations. Even at room temperature, a quantitative yield was achieved by using either 2 mol% of [P66614]Cl in dichloromethane or a planetary ball mill. The unexpected finding that phosphane-free [P66614]Cl also allows the quantitative synthesis of Ag2Te at 60°C implies an additional activation mechanism independent from the phosphane, which is yet unknown.[20] Subsequently, the manifoldly-used lighter chalcogen sulphur is tested for the synthesis of sulphides. Direct synthesis of binary sulphides of B, Bi, Ge, Mo, Cu, Au, Sn, In, Ti, V, Fe, Co, Ga, Ni, Al, Zn, and Sb in [P66614]Cl was tested at 100 °C, i.e. below the melting point of sulphur. Under these conditions, substantial sulphide formation occurred only for nickel (Ni3S4, Ni3S2, NiS) and copper (Cu2S, CuS). Sb showed no formation of crystalline sulphide, but after addition of EtOH, an orange material precipitated which was identified as amorphous metastibnite.[21] As generating these elements from their ores is highly energy consuming, direct dissolution experiments of the crystalline stibnite in [P66614][OAc] and Cl– were investigated and resulted in yellow solutions, from which the amorphous form can be precipitated upon exposure to EtOH air without any sign of decomposition of the IL. In particular, follow-up investigations were conducted on the solubility of Sb2S3 for follow-up chemistry in the LEWIS-acidic IL [BMIm]Cl · 4.7 AlCl3 at 160 °C which resulted in the formation of the novel chloride-terminated [Sb13S16Cl2]5+ quadruple-heterocubane cation-containing compound [Sb13S16Cl2][AlCl4]5.[21] Addition of CuCl in a slightly modified reaction resulted in the formation of the layered semiconductor Cu(Sb2S3)[AlCl4]. From this the AlCl3 can be leached by treatment with 0.1 molar hydrochloric acid, yielding a compound with the presumed composition Cu(Sb2S3)Cl.[22] As ILs showed to be able to activate elements that are insoluble in common solvents, and the formation of Sb2S3 from reactions mixtures of the elements raised the question of whether only the sulphur forms a mobile species or if antimony could additionally activated, the synthesis of binary antimony compounds directly from elements was explored as they are highly discussed as replacements for silicon-based semiconductors. Therefore the 12 elements Ti–Cu, Al, Ga, In, and Te, which are known to form binary compounds with Sb, were reacted with Sb in [P66614]Cl under inert conditions in a simple closed glass flask with vigorous stirring for 16 h at 200 °C. This resulted in the formation of NiSb, InSb, Cu2Sb and Sb2Te3. The applied reaction temperature is several hundred degrees below the temperatures required for solvent-free conversions. Compared to reactions based on diffusions in the solid state, reaction times are much shorter. The IL is not consumed and can be recycled. Since the reaction with Cu showed almost complete conversion, the influences of reaction time, temperature and medium were further investigated. In a diffusion experiment, Cu2Sb formed on the copper, which indicates that antimony forms mobile species in these ILs. These systematic studies hence deliver a contribution to how ILs can help in the synthesis of new materials and how they can make a difference in the synthesis of inorganic materials as well in the context of “GREEN CHEMISTRY”. This can help in developing a more educated choice/toolbox of IL systems for reducing energy costs by reducing the temperature from high temperature inorganic syntheses to syntheses near room-temperature by using the elements as starting materials, with a high atom economy for the synthesis of known and new materials.

The Abraham solvation model (ABSM) is an experimentally derived predictive model used to help predict various solute properties. This work covers various uses for the ABSM including predicting molar enthalpies of vaporization, predicting solvent coefficients for two new solvents (2,2,5,5-tetramethyloxolane and diethyl carbonate), predicting values for multiple new ionic liquids (ILs). This work also introduces a novel method for updating IL ABSM parameters by updating cation- and anion-specific values using linear algebra and binary matrices.

Molecular dynamics (MD) simulation studies were considered in this study in the fields of phosphonium based ionic liquids (PBILs) and heterogeneous (solid/liquid) zeolite systems. A new generation of ionic liquids (ILs) called phase-separable ionic liquids (PSILs) are able to dissolve cellulose and lignin, a necessary step, for conversion of biomass to fuels and chemicals with co-solvents and are immiscible with water or saline solutions. Molecular simulations on these systems will provide insights of phase behavior and dissolution phenomenon. The knowledge of interfacial phase behavior of ionic liquids/solvent systems is critical for materials discovery for designing efficient dissolution processes. Transition zone from miscible to immiscible behavior was observed for alkyl chain lengths varying from 6 to 8. Emulsion phase was observed for [P8888]+ ion. Result from molecular dynamics (MD) simulations shows excellent agreement with experimental data for both chloride and acetate anions. These contributions will be helpful in modeling PBILs system for cellulose dissolution, liquid-liquid extraction and biomass studies. Another important aspect in biofuel conversion is glucose isomerization step using zeolites. Zeolites are crystalline solids that have wide applications in industrial areas for its hydrocarbon conversion, adsorption of molecules. In this study, we report MD simulation studies on glucose solution diffusion into zeolite structure as a function of temperature and pressure. Development of united-atom force field for PBILs, for phosphonium cation with anions of chloride and acetate, is considered in this study. Force field parameterization was considered for these ionic liquids with a variation of alkyl chain length in phosphonium ion with chloride and acetate anions. Performance of force field parameters was analyzed by calculating properties such as density and viscosity at various temperature and compared with available experimental data. Efficient algorithm techniques were developed in molecular simulations that will reduce computational load in calculating non-bonded interactions. We introduce theory of local sample (TLS) in calculating non-bonded interactions acting on atoms. Another algorithmic improvement in MD simulations is calculating force acting on atoms based on previous time steps, that achieves up to 50 % reduction in computational time