Ce travail de thèse est consacré à l’étude du vieillissement UV d’un caoutchouc EPDM (éthylène propylène diène monomère) avec une attention spéciale sur les additifs du système de vulcanisation. Pour cela nous avons utilisé des techniques particulièrement adaptées à l’analyse de surface telles que le ToF-SIMS, l’XPS, l’ATR-FTIR, le MEB-EDX et l’AFM. Dans un premier temps nous avons pu déterminer la composition chimique de la surface du caoutchouc EPDM vulcanisé à l’état initial. Nous avons pu identifier les sous-produits de vulcanisation et déterminer de manière qualitative leur répartition en surface. Les profils en profondeur ToF-SIMS ont permis de mettre en évidence une couche d’enrichissement en additifs à le surface du caoutchouc dont l’origine pourrait provenir de leur migration par cristallisation ou « effet bloom » par vulcanisation. Dans la seconde partie, nous avons étudié l’effet du vieillissement artificiel SEPAP sur le caoutchouc et sur les additifs. Nos résultats montrent que la surface du caoutchouc ainsi que les deux accélérateurs de vulcanisation, le MBTS (2,2’-Dithiobis(benzothiazole)) et le ZBPT (Zinc O, O-Dibutylphosphorodithioate) subissent des changements chimiques et morphologiques profonds caractérisés par une oxydation chimique et une dégradation structurale. Les études cinétiques ont montré que les changements chimiques les plus importants étaient observés pendant les 100 premières heures. Nous avons examiné un caoutchouc industriel, actuellement utilisé dans l’étanchéité de carrosserie, afin de mieux comprendre le comportement des agents de mise en oeuvre à l’état initial et au cours du vieillissement. Ces agents de mise en oeuvre jouent un rôle clé dans la composition chimique du caoutchouc à l’état initial malgré la faible quantité incorporée. Nous avons montré que ces composés recouvrent la surface et forment une couche épaisse d’environ 500 nm, très résistante au vieillissement. / This thesis is devoted to the study of UV aging of an EPDM rubber with particular emphasis on additives involved invulcanization. For this purpose, we use techniques suitable for surface analysis such as ToF-SIMS, XPS, ATR-FTIR, SEMEDXand AFM. We first determine the initial chemical composition of the surface of the EPDM rubber. We identify the by-products of vulcanization and qualitatively determine their distribution on the surface. The ToF-SIMS depth profiles exhibit a layer enriched in additives on the surface of the rubber due to migration by crystallization or by the “bloom effect” after vulcanization. In addition, images from 3D profiles show that some of these additives are adsorbed on the no-black fillers. In the second part, we study the effect of artificial aging on the rubber and the additives. Our results indicate that both the surface of the rubber and the two rubber accelerators, MBT and ZBPT, undergoes significant chemical and morphological changes characterized by chemical oxidation and structural degradation. Our Kinetic studies show that the most important chemical changes take place during the first 100h. The final chapter is devoted to the study of industrial rubber, currently used in vehicle body seals, and discusses on understanding of the behavior of the processing agents in the initial state and during aging. These agents play a key role in the chemical composition of the rubber in the initial state, despite the small amounts incorporated. We show that these compounds cover the surface and form a layer about 500 nm thick, very resistant to aging.

No description available.

I det här projektet har uppgiften varit att rena vattnet i Aqua Interiör i Laholms egen tillverkade vattenmöbel med hjälp av uv-ljus. Dessa möbler hyr de ut till kunder för att kunna få ett lagom kallt vatten med eller utan kolsyra. Vattenmöblerna är direkt kopplade till det befintliga vattensystemet. Ett problem som de tidigare haft är att de inte kunnat ha sina möbler på sjukhus eftersom möblens beskaffenhet medför en ökad bakteriehalt i vattnet.Denna bakteriehalt kommer dock inte upp till den gräns som livsmedelverkets satt som icke tjänligt. På sjukhus finns ett högre krav på vattnets kvalité där inga anmärkningar får finnas på vattnet. Vid uv-bestrålning hoppas man att detta problem kommer att lösas.Det har tagits fram en reaktor där vattnet uv-bestrålas i en spiral gjord av kvartsglas. Ett styrkort har tagits fram för att styra bestrålningen av vattnet och att ha kontroll på att inga problem med bestrålningen uppkommer.En display med touchfunktion har använts för att på ett snyggt sett presentera viktig information om lampans status och temperatur inne i reaktorn. Detta för att serviceman på vattenmöbeln ska få information på om lampan behöver bytas eller inte. En inloggning i systemet skapades för att förvissa sig om att inga obehöriga skulle ha möjlighet att radera den loggdata som skapas. Med touchdisplayen har man fått en gedigen känsla av kvalite och ny teknik.Användningen av detta uv-filter har resulterat i att vattnet har renats med ett positivt resultat. Förhoppningen är att en vidare utveckling på det här projektet kommer leda till en färdig produkt som kommer säljas/uthyras av Aqua Interiör i Laholm. / The objective with this project has been to purify water in the Aqua Interiör in Laholm proprietary water furniture using uv-light. These furnitures are rent out to customers to get moderately cold water, with or without sparkling. The water furnitures is directly connected to the water system. A problem with the water furniture is that it is not suitable for hospitals because there is an increased bacterial content in the water, however, below the prescribed limits. In hospitals there is a higher requirement for water quality. The objective with the uv-radiation is to solve this problem. A reactor has been developed in which the water is uv-radiated in a spiral made of quartz glass. A control system controls the radiation of the water and that no problem occurs during the radiation.A display with touch-function has been used to get an attractive way to present important information about lamp status and temperature inside the reactor. This is how the service personnel receive information on the lamp if it needs replacing or not. A log of the system was created to ensure that no unauthorized person would be able to delete the log data that is created. The touch-display made it a solid feeling of quality and new technology.The use of the uv filter has resulted in a positive result, with purified water. An ambition is that further development of this project will lead to a finished product that will be sold / out rented by Aqua Interiör i Laholm .

This study evaluated the performance of advanced oxidation processes that combines UV, O3 and H2O2 to mineralize N-methyl-2-pyrrolidinone (NMP) in an aqueous solution. As a photoresist stripper, NMP is widely used in the semi-conductor and optoelectronics industries, and difficult to be degraded by bio-treatment of wastewater. The concentration of total organic carbon (TOC) was selected as a mineralization index of the decomposition of NMP by the advanced oxidation process. Results of this study indicate that UV irradiation 37.2 mWcm−2 UV(254 nm) and O3 doses of 5¡Ñ10-4 mol/min causes the best 89% mineralization of NMP (20 mg/L) over a reaction time of 60 minitues and the the mineralization efficiency follows the sequence of UV/O3 (89%)¡ÖUV/H2O2/O3 (58%)¡ÖO3/H2O2 (48%)¡ÖO3 (42%)¡ÖUV/H2O2 (34%). The effect of the initial NMP concentration over the range of 20 to 80 mg/L on the mineralization rate of NMP was studied, and the experimental results indicates that the mineralization efficiency of NMP declines as the initial NMP concentration increases, the mineralization efficiencies were 89%¡B82%¡B61%¡B54% after a reaction time of 60 min. This result indicates that the photocatalytic mineralization of NMP by UV/O3 is not simple first-order but pseudo first-order. Since NMP generates organic acid compounds, which cannot easily be decomposed by hydroxide radicals (⋅OH ) before fully mineralization, a higher concentration of NMP results in a higher concentration of organic acid compounds. Hence, the mineralization rate of more highly concentrated NMP is lower. The pseudo first-order rate constant (kobs) is calculated between 0.0365~0.0127 min-1 and half-life (t1/2) between 18.99~54.58 minitues. The existence of the H2O2 may influence the NMP mineralization rate in the UV/O3 system, because H2O2 plays the role of initiator and scavenger at the same time. The experiment results inducate that as the concentration of H2O2 increases, the mineralization rate of NMP declines. In the UV/O3 system, the H2O2 consumed hydroxide radicals and acted as a scavenger of hydroxide radical. Adding H2O2 to the UV/O3 system has a negative effect of NMP mineralization. Adding ferrous ions is likely to reduce the mineralization rate of NMP, the mineralization efficiency reduces from 89% to 48% as the ferrous ions increses from 0 mg/L to 10 mg/L, because the ferrous ions in the solution are oxidized into the ferric hydroxide precipitate in a UV/O3 environment and produce turbidity in the reactor. This precipitation phenomenon somewhat obstructs the penetration of UV light. UV/O3 is less capable of mineralizing NMP. The presence of ferrous ions reduces the effectiveness of UV/O3 in mineralizing NMP. The result indicates that this pH range does not affect the mineralization process. The pseudo first-order rate constant (kobs) is calculated between 0.0349~0.0362 min-1 and half-life (t1/2) between 19.15~19.86 minitues over the range of pH:3.0 to pH:10.0 in the UV/O3 system. The pH values of the solution do not affect the mineralization efficiency of the UV/O3 process. The results also show that in highly SO42- and ClO4- ionic environment, NMP mineralization is not suppressed, indicating that a highly ionic environment does not negatively affect the generation of hydroxide radical by UV/O3 system.

Plants can respond differently to different wavelengths in sunlight's spectral range, and crop covers containing additives have a great effect on the growth of crops. This research focuses on synthesising new hydroxybenzophenones bearing long alkyl chains to confer polymer solubility, and to measure their UV absorption and photochemical stability. Compounds substituted with fluorine atoms or different amino groups in particular were under investigated, as these groups may impart stability towards oxidative degradation, or alter the absorption maximum. Related naphthalene analogues were substituted with different amine groups for comparing UV absorption and photostability. Modification of Uvinul A Plus was carried out to improve UV absorption maximum wavelength and light fastness.

This study was to investigate the treatment of paraquat-containing solutions by advanced oxidation processes (denoted by AOPs). The operation parameters conducted in semi-batch reactor were as follows: the effect of ozone dose, pH and H2O2 concentration on conversion of paraquat by adding O3, UV, O3/H2O2, UV/H2O2 and UV/O3/H2O2. Paraquat concentration: 10 ppm and 20 ppm, ozone dose: 45 g/hr and 105 g/hr, and H2O2 concentration: 0,07 g/l, 0.71 g/l and 1.127 g/l were tested. In the first stage of pre-test, the purpose was to observe the decomposition of paraquat under various pH in order to compare the conversions by O3 and by O2, and to select the optimal pH in above AOPs. The performances of AOPs for treating paraquat-containing solutions were found in sequence as follows: O3/H2O2, O3, UV/O3, UV/H2O2/O3, UV/H2O2 and UV. The process of O3/H2O2 not only could remove higher concentration of paraquat but also had to need a shorter residence time. The effect of parameters on the removal of paraquat by each AOPs were discussed. The kinetics of AOPs in treatment of paraquat-containing solutions was confirmed by using half-life test. Except UV and UV/H2O2 processes nearing zero order, the apparent reaction order of O3, UV/O3, UV/O3/H2O2 and O3/H2O2 were obtained to be one. Based on the removal and cost analysis, O3/H2O2 (O3 = 45 g/hr, H2O2 dose = 0.71 g/l) was the best process in treating paraquat solutions for the low energy and economic cost. As for the O3 and UV/O3 processes, we also recommended to be yours truly options.

In an effort to be able to use photoinitiators to their maximum potential, the sequence of events that occurs in an ink formulation during the UV curing process has have been studied and information presented to allow more effective formulation. Emphasis has been placed on highlighting the variables that have the greatest impact both on photoinitiator efficiency and on the suitability of individual photoinitiators and synergists for use in particular applications. These variables were found to be photoinitiator thermal stability, UV light utilisation, reaction mechanisms and cure reactivity. A wide range of photoinitiators and synergists were investigated using thermogravimetric analysis (TGA) and thermogravimetric analysis-mass spectroscopy (TGA-MS) to define both their thermal stability and whether under heating they thermally decompose or merely evaporate. Differential photocalorimetry (DPC) was used to determine which wavelengths from a typical medium pressure mercury curing lamp are the most important for providing cure, with both theoretical and practical methods being used to define the extent to which these wavelengths penetrate into pigmented and non-pigmented coatings. A procedure was devised and validated for this purpose. The reaction mechanism and photodecomposition products of a range of photoinitiators were investigated using gas chromatography-mass spectroscopy (GC-MS) and radical trapping experiments. The reaction mechanisms are discussed in terms of available literature knowledge. Evidence is also presented suggesting that, with only particular exceptions, cleavage photoinitiators can also react by a hydrogen abstraction mechanism in the presence of an amine synergist. A real time infrared spectrometer (RTIR) was set up and a method validated for following the UV curing reaction through changes in the acrylate double bond concentration. The advantages and disadvantages of this instrument are discussed in terms of other similar instruments reported in the literature, and the technique subsequently used to measure the reaction rates of a wide range of photoinitiators. Other factors such as photoinitiator concentration, amine synergist type I level and formulation viscosity were also investigated to determine their influence on the cure process.

No description available.

No description available.

No description available.