Poly(butylene succinate) (PBSu), poly(2-methyl-1,3-propylene succinate) (PMPSu), and their two novel poly(butylene succinate-co-2-methyl-1,3-propylene succinate)s (PBMPSu 95/05 and PBMPSu 90/10) were synthesized by a two-stage esterification reaction. PBMPSu 95/05 and PBMPSu 90/10 were characterized as having 6.5 and 10.8 mol% 2-methyl-1,3-propylene succinate (MPS) units, respectively, by 1H NMR. These copolymers were characterized to be random from the 13C NMR spectra. In this study, the nonisothermal crystallization and thermal degradation behaviors of the polyesters were investigated via different approaches. A differential scanning calorimeter (DSC) and a polarized light microscope (PLM) were employed to investigate the nonisothermal crystallization of these copolyesters and neat PBSu. Morphology and the isothermal growth rates of spherulites under PLM experiments at three cooling rates of 1, 2.5 and 5 ¢XC/min were monitored and obtained by curve-fitting. These continuous rate data were analyzed with the Lauritzen-Hoffman equation. A transition of regime II ¡÷ III was found at 96.2, 83.5, and 77.9 ¢XC for PBSu, PBMPSu 95/05, and PBMPSu 90/10, respectively. DSC exothermic curves at five cooling rates of 1, 2.5, 5, 10 and 20 ¢XC/min show that almost all of the nonisothermal crystallization occurred in regime III. DSC data were analyzed using modified Avrami, Tobin, Ozawa, Mo, Friedman and Vyazovkin equations. All the results of PLM and DSC measurements reveal that incorporation of minor MPS units into PBSu markedly inhibits the crystallization of the resulting polymer. The nonisothermal crystallization behavior of these polyesters was also investigated using a Fourier-transform infrared spectrometer (FTIR) with an attenuated total reflection (ATR). The absorbance peaks of crystals for the £\ form (918, 955, and 1045 cm-1) of PBSu and PBMPSu copolyesters were observed by ATR-FTIR under nonisothermal crystallization. When these semicrystalline polyesters started to be solidified from the melt state, these characteristic absorption bands for PBSu and its copolyesters crystals have been detected. In this study, the thermal degradation mechanisms of PBSu, PMPSu, PBMPSu 95/05, and PBMPSu 90/10 were investigated using a thermogravimetric analyzer combined Fourier-transform infrared spectrometer (TGA-FTIR) and a pyrolysis-gas chromatography¡Vmass spectrometry (Py-GC-MS). The volatile products evolved from the thermal degradation of these two copolyesters were identified to be anhydride, ether, ester, alcohol, alkene, aldehyde, and CO2. FTIR spectra displayed that the main degradation products for these four polymers were anhydrides. Moreover, PBSu-rich PBMPSu copolymers exhibited the same thermal degradation mechanism as that of PBSu at lower thermal degradation temperatures (< 403 ºC) and as that of PMPSu at higher thermal degradation temperatures (> 403 ºC) by the TGA-FTIR analysis. The results of the TGA-FTIR analysis clearly demonstrates that the influence of MPS units on the thermal degradation process is gradually increased as the temperature increases for PBMPSu copolymers. The degradation mechanism of PBMPSu at lower thermal degradation temperatures and PBSu mainly follows the £]-hydrogen bond scission mechanism and the back-biting process from the polymer chains. Moreover, the degradation mechanism of PBMPSu at higher thermal degradation temperatures and PMPSu occurred mainly through the £]-hydrogen bond scission and secondarily through £\-hydrogen bond scission. Finally, the thermal stability and degradation kinetics of these polyesters were investigated using a TGA at heating rates of 1, 3, 5, and 10 ºC/min under dynamic nitrogen. The activation energies of thermal degradation in elective conversions were estimated using the Friedman and Ozawa methods. The results clearly demonstrated that the thermal stabilities of these PBMPSu copolyesters were slightly reduced with the incorporation of minor MPS units into PBSu. Two model-fitting methods of nth-order and autocatalysis nth-order reaction mechanisms were adopted to determine the mass loss function f(£\), the activation energy and the associated degradation parameters. The results revealed that the mechanism of autocatalysis nth-order fitted the experimental data much more closely than did the nth-order mechanism for PBSu, PMPSu and PBMPSu copolymers.

The invention of Li-ion batteries (LIBs) marks a new era of energy storage and allows for the large-scale industrialization of electric vehicles. However, the flammable organic electrolyte in LIBs raises significant safety concerns and has resulted in numerous fires and explosion accidents. In the pursuit of more reliable and stable battery solutions, interests in aqueous batteries composed of high-energy cathodes and water-based electrolytes are surging. Limited by the narrow electrochemical stability window (ESW) of water, conventional aqueous batteries only achieve inferior energy densities. Current development mainly focuses on manipulating the properties of aqueous electrolytes through introducing excessive salts or secondary solvents, which enables an unprecedentedly broad ESW and more selections of electrode materials while also resulting in some compromises. On the other hand, the interaction between electrodes and aqueous electrolytes and associated electrode failure mechanism, as the key factors that govern cell performance, are of vital importance yet not fully understood. Owing to the high-temperature calcination synthesis, most electrode materials are intrinsically moisture-free and sensitive to the water-rich environment. Therefore, compared to the degradation behaviors in conventional LIBs, such as cracking and structure collapse, the electrode may suffer more severe damage during cycling and lead to rapid capacity decay. Herein, we adopted multi-scale characterization techniques to identify the failure modes at cathode–electrolyte interface and provide strategies for improving the cell capacity and life during prolonged cycling. In Chapter 1, we first provide a background introduction of conventional non-aqueous and aqueous batteries. We then show the current development of modern aqueous batteries through electrolyte modification and their merits and drawbacks. Finally, we present typical electrode failure mechanism in non-aqueous electrolytes and discuss how water can further impact the degradation behaviors. In Chapter 2, we prepare three types of aqueous electrolytes and systematically evaluate the electrochemical performance of LiNixMnyCo1-x-yO2, LiMn2O4 and LiFePO4 in the aqueous electrolytes. Combing surface- and bulk-sensitive techniques, we identify the roles played by surface exfoliation, structure degradation, transition metal dissolution and interface formation in terms of the capacity decay in different cathode materials. We also provide fundamental insights into the materials selection and electrolyte design in the aqueous batteries. In Chapter 3, we select LiMn2O4 as the material platform to study the transition metal dissolution behavior. Relying on the spatially resolved X-ray fluorescence microscopy, we discover a voltage-dependent Mn dissolution/redeposition (D/R) process during electrochemical cycling, which is confirmed to be related to the Jahn–Teller distortion and surface reconstruction at different voltages. Inspired by the findings, we propose an approach to stabilize the material performance through coating sulfonated tetrafluoroethylene (i.e., Nafion) on the particle, which can regulate the proton diffusion and Mn dissolution behavior. Our study discovers the dynamic Mn D/R process and highlights the impact of coating strategy in the performance of aqueous batteries. In Chapter 4, we investigate the diffusion layer formed by transition metals at the electrode–electrolyte interface. With the help of customized cells and XFM technique, we successfully track the spatiotemporal evolution of the diffusion layer during soaking and electrochemical cycling. The thickness of diffusion layer is determined to be at micron level, which can be readily diminished when gas is generated on the electrode surface. Our approach can be further expanded to study the phase transformation and particle agglomeration at the interfacial region and provide insights into the reactive complexes. In Chapter 5, we reveal the correlation between the electrolytic water decomposition and ion intercalation behaviors in aqueous batteries. In the Na-deficient system, we discover that overcharging in the formation process can introduce more cyclable Na ions into the full cell and allows for a boosted performance from 58 mAh/g to 124 mAh/g. The mechanism can be attributed to the water oxidation on the cathode and Na-ion intercalation on the anode when the charging voltage exceeds the normal oxidation potential of cathode. We emphasize the importance of unique formation process in terms of the cell performance and cycle life of aqueous batteries. In Chapter 6, we summarize the results of our work and propose perspectives of future research directions. / Doctor of Philosophy / Li-ion batteries (LIBs) have dominated the market for portable devices and electric vehicles owing to their high energy density and good cycle life. However, frequent battery explosion accidents have raised significant safety concerns for all customers. The root cause can be attributed to the flammable organic electrolytes in conventional LIBs. To address this issue, aqueous batteries based on water-rich electrolytes attract intensive attention recently. Recent research progress has dramatically improved the energy density of aqueous batteries dramatically by modifying the properties of electrolytes. However, most electrode materials are incompatible with water, leading to severe side reactions and an unstable cycle life. Therefore, understanding the failure mechanism of electrode materials in the presence of water is crucial while not fully studied yet. Our projects systematically evaluate the degradation behavior of various electrodes in aqueous electrolytes and uncover the root cause of transition metal dissolution in the electrodes. Our studies shed light on improving battery capacity and cycle life through a specialized formation cycle and polymer coating process. Furthermore, we also provide new approaches to investigate the dynamic process occurring at electrode–electrolyte interface, which is applicable to other solid–liquid systems. In summary, our research reveals the correlation between the failure mechanism and the capacity decay in various electrode materials, proposing effective approaches to enhance the battery performance.

No description available.

Solid oxide fuel cells (SOFCs) represent a next generation energy source with high energy conversion efficiency, low pollutant emission, good flexibility with a wide variety of fuels, and excellent modularity suitable for distributed power generation. As an electrochemical energy conversion device, SOFC’s performance and reliability depend sensitively on the catalytic activity and stability of the electrode materials. To date, however, the development of electrode materials and microstructures is still based largely on trial-and-error methods because of inadequate understanding of the mechanisms of the electrode processes. Identifying key descriptors/properties of electrode materials or functional heterogeneous interfaces, especially under in situ conditions, may provide guidance to the design of electrode materials and microstructures. This thesis aims to gain insight into the electrochemical and catalytic processes occurring on the electrode surfaces using unique characterization tools with superior sensitivity, high spatial resolution, and excellent surface specificity applicable under in situ/operando conditions. Carbon deposition on nickel-based anodes is investigated with in situ Raman spectroscopy and SERS. Analysis shows a rapid nucleation of carbon deposition upon exposure to small amount of propane. Such nucleation process is sensitive to the presence of surface coating (e.g., GDC) and the concentration of steam. In particular, operando analysis of the Ni-YSZ boundary indicates special function of the interface for coking initiation and reformation. The coking-resistant catalysts (BaO, BZY, and BZCYYb) are systematically studied using in situ Raman spectroscopy, SERS, and EFM. In particular, time-resolved Raman analysis of the surface functional groups (-OH, -CO3, and adsorbed carbon) upon exposure to different gas atmospheres provides insight into the mechanisms related to carbon removal. The morphology and distribution of early stage carbon deposition are investigated with EFM, and the impact of BaO surface modification is evaluated. The surface species formed as a result of sulfur poisoning on nickel-based anode are examined with SERS. To identify the key factors responsible for sulfur tolerance, model cells with welldefined electrode-electrolyte interfaces are systematically studied. The Ni-BZCYYb interface exhibits superior sulfur tolerance. The oxygen reduction kinetics on LSCF, a typical cathode material of SOFC, is studied using model cells with patterned electrodes. The polarization behaviors of these micro- electrodes, as probed using a micro-probe impedance spectroscopy system, were correlated with the systematically varied geometries of the electrodes to identify the dominant paths for oxygen reduction under different electrode configurations. Effects of different catalyst modifications are also evaluated to gain insight into the mechanisms that enhance oxygen reduction activity. The causes of performance degradation of LSCF cathodes over long term operation are investigated using SERS. Spectral features are correlated with the formation of surface contamination upon the exposure to air containing Cr vapor, H2O, and CO2. Degradation in cathode performance occurs under normal operating conditions due to the poisoning effect of Cr from the interconnect between cells and the high operating temperature. The surface-modified LSCF cathode resists surface reactions with Cr vapor that impairs electrode performance, suggesting promising ways to mitigate performance degradation.

In unserem alltäglichen Leben nehmen Kunststoffe eine immer größere Rolle ein. Die organische Struktur dieser Materialien bedingt die Brennbarkeit derselbigen und birgt somit eine Gefahr, die allgegenwärtig ist. Flammschutz von Polymeren ist daher eine wichtige Eigenschaft. Der Markt an Flammschutzadditiven ist bereits sehr breit gefächert. Allerdings gibt es nur wenig Studien, die systematisch Struktur und Flammschutzwirkung betrachten. So war es das Ziel dieser Arbeit, durch die Untersuchung zweier systematisch variierter Polymergruppen Struktur-Eigenschafts-Beziehungen zu entwicklen, die das Verständnis von Flammschutzadditiven erweitern. Die erste Gruppe bestand aus Polyestern mit einem gleichbleibenden Polymerrückrat an dem phosphorhaltige Seitenketten systematisch variiert wurden. In der zweiten Gruppe wurde das Polymergrundgerüst bei gleichbleibendem Substituenten variiert. Die Strukturen wurden umfassend hinsichtlich ihres Abbaus untersucht, so das durch Korrelation von Abbauverhalten und erarbeiteten Abbaumechanismen Zusammenhänge zwischen der nativen Polymerstruktur und dem Flammschutzverhalten gefunden werden konnten. Es lässt sich nachweisen, dass das Hauptabbaumaximum fast vollständig durch die Polymergrundkette dirigiert wird. Der Substituent hat wenig Einflauss darauf, womit sich die Möglichkeit ergibt Flammschutzadditive gezielt and das Abbaumaximum des zu schützenden Matrixpolymers anzupassen. Die strukturelle Veränderung des phosphorhaltigen Substituenten hingegen ermöglich es das Flammschutzadditv in seiner Wirkungsweise, also Aktivität in der Gasphase oder kondensierten Phase, anzupassen. Sehr wesentlich, besonders mit Blick auf die Rückstandbildung, ist das Zusammenspiel zwischen Substituent und Polymerrückgrat. Bei geeigneter Wahl aliphatischer und aromatischer Anteile lassen sich so Flammschutzadditive herstellen, die einerseits gut zu verarbeiten sind, andererseits aber auch einen möglichst hohen Rückstand erzeugen. Mit Kenntnis dieser Struktur-Eigenschafts-Beziehungen ist es zukünftig möglich, polymere Flammschutzadditive zielgerichteter zu entwickeln. So lässt sich das Additiv in seiner Wirkung nicht nur an das Matrixpolymer anpassen, sondern auch an die primären Brandgefahren in dessen Endanwendung. Eine Under-the-hood-Anwendung im Automobilbau fordert andere Flammschutzeigenschaften als die Verwendung im häuslichen Küchenbedarf.

An important challenge for PEMFC is stability and durability of the membrane separator. In this dissertation, we applied both experimental and modeling methods to investigate the chemical durability of PFSA membranes for fuel-cell applications. Degradation data were collected after Fenton's tests and the membrane samples were analyzed by XPS after Fenton's test; FTIR was also invoked to validate the XPS results. The effects of Fe2+ concentration and temperature on membrane degradation were discussed. The experimental results provide evidence of chemical attack of the CF2 backbone. Since the level of H2O2 was found to be key to membrane degradation, we designed a novel spectrophotometric method to quantitatively determine H2O2 concentration in a fuel cell by using a multilayer MEA. In addition, a model for H2O2 formation, transport, and reaction in PEMFCs is established for the first time to validate experimental data and study formation mechanism. The humidity effect on membrane degradation was studied by collecting vent water during the tests. The membrane conductivities and mechanical properties were measured by ex-situ high-throughput instruments. FTIR was applied to study both the formation of new groups and the relative abundance of existing groups in the degraded membrane. The thermal stability of degraded membranes was determined by TGA. The cross section of a degraded MEA sample was imaged with SEM to investigate the mechanical structure change. The effect of temperature on membrane degradation was also investigated. XPS spectra were collected from both anode and cathode sides of fuel-cell membrane to compare the effect of temperature on each side. Atomic analysis was performed to study the impact of temperature on both backbone decomposition and side group degradation. A multilayer MEA was used to study the effects of location and thickness on membrane degradation. An improved kinetic model of membrane degradation was built to simulate the experimental data. Finally, an attempt to mitigate membrane degradation by using peroxide decomposition reagent was performed. OCV curves were recorded during two fuel-cell durability tests with and without the addition of this additive. Both FER and TER were compared. Recommendations for the improvement of peroxide decomposition additive were suggested.

Ce travail de thèse est axé sur le développement d'une technique de traitement chimique par déchloration réductrice de l'hexachlorobutadiène (HCBD) et de l'hexachloroéthane (HCA). La première partie a consisté en l'acquisition de données expérimentales de solubilité des deux composés (i) à différentes températures et (ii) en présence de surfactants. Les essais en température ont notamment permis de proposer, par le calcul des variations des grandeurs thermodynamiques de dissolution, une explication physique à la présence d'un minimum de solubilité entre 12 et 45 °C. La seconde partie, basée sur une étude préalable de sélection d'un réactif pour son efficacité, a consisté principalement en l'étude du mécanisme de déchloration réductrice par les microparticules de Pd/Fe en suspension dans l'acide polylactique, un polymère biodégradable. Différentes conditions expérimentales ont permis de démontrer que l'hydrogène atomique est le principal réducteur du système. Plusieurs lois cinétiques ont ensuite été utilisées pour la modélisation de la disparition de HCBD et HCA en études individuelles et en mélange. / This work focused on the reductive dechlorination of hexachlorobutadiene (HCBD) and hexachloroethane (HCA). The first part consisted of experimental measurement of solubility data for both compounds (i) at different temperatures and (ii) in the presence of surfactants. Thermodynamic parameters for dissolution have been calculated in order to propose a physical explacation of the minimum solubility observed between 12 and 45 °C. The second part, based on a preliminary selection of a reaction for its efficiency, aimed to investigate the mechanism of the reductive dechlorination of HCBD and HCA by Pd/Fe microparticles in suspension in polylactic acid. Different experimental conditions have shown that atomic hydrogen is the main reductant of the system. Different kinetic laws were then used for the modeling of the disappearance of HCBD and HCA, taken separately and in mixture.

Cette thèse explore le vieillissement des modules photovoltaïques (PV) à base de silicium cristallin via une approche multi-matériaux. L’objectif premier est de déterminer les mécanismes de dégradation mis en jeu durant l’exploitation des modules PV et ainsi d’être à même de proposer des solutions technologiques améliorant leur durabilité. Pour cela, des tests de vieillissement accéléré ont été réalisés sur le verre, la cellule PV au silicium cristallin et le mini-module PV composé du verre, d’un polymère encapsulant et de la cellule silicium.Leurs propriétés fonctionnelles sont systématiquement évaluées et le suivi dans le temps de ces indicateurs permet de définir des lois de vieillissement. En parallèle, des caractérisations physico-chimiques sont réalisées pour définir les mécanismes de dégradations des différents constituants du module. L‘étude de la chaleur humide sur le verre a permis de mettre en évidence une dégradation de surface via un processus d’hydratation du réseau vitreux et un phénomène de lixiviation du sodium qui engendre une augmentation de la transmittance du verre. La cellule PV présente des performances électriques et une réflectance dégradées suite à l’exposition aux radiations UV dues à un processus de photo-oxydation de la couche antireflet SiNx. Il a également été établit qu’une puissance UV élevée peut aussi favoriser un phénomène de régénération des performances électriques. Le vieillissement du mini-module sous UV a montré du phénomène de dégradation photo-induite (LID) engendrant une légère diminution des performances électriques dès la première exposition alors que l’impact de la chaleur humide sur les performances électriques est nul après 2000 heures d’exposition / This thesis investigates the aging of photovoltaic (PV) modules based on crystalline silicon technology via a multi-material approach. The first objective is to determine the degradation mechanisms involved during the operation of the PV modules and thus to be able to propose technological solutions improving their durability. For this purpose, accelerated aging tests were carried out on the glass, the crystalline silicon PV cell and the PV mini-module composed of glass, a polymeric encapsulant and the silicon cell.Their functional properties are systematically evaluated and the follow-up of these indicators allows to define aging laws. In parallel, physicochemical characterizations are carried out to determine the degradation mechanisms of the different components of the module. The study of damp heat on glass throws into evidence a surface degradation with a hydration process of the silica network and a leaching phenomenon of the sodium which involves an increase of the glass transmittance. The PV cell exhibits a deterioration of the electrical performance and reflectance after UV radiation exposure due to a photo-oxidation process of the SiNx antireflection layer. It has also been established that high UV power can also promote a regeneration phenomenon of electrical performances. The aging of the mini-module under UV shows the phenomenon of photo-induced degradation (LID) generating a slight decrease in the electrical performance from the first exposure whereas the impact of damp heat on the electrical performance is null after 2000 hours

Maritime transportation emits about 3% of global greenhouse gas, International Maritime Organization (IMO) aims to reduce shipping’s emissions by 50% with respect to 2008 levels. Proton exchange membrane fuel cells (PEMFCs) are considered among the most promising clean technologies for decarbonizing the maritime sector. One of the challenges for commercial application of PEMFCs is their limited durability. The purpose of this thesis was to assess the most significant degradation mechanisms and operating conditions of the PEMFC in marine applications, including membrane and catalyst layer degradation during idle, start-stop cycles, and dynamic load cycles, and to build a model to forecast the lifetime.A semi-empirical approach was developed to evaluate the PEMFC lifetime through a 2D COMSOL model. The model takes into account the empirical relationships for membrane conductivity loss and electrochemical surface area (ECSA) decay as functions of cycling numbers, aging process, and idling time. The 2D model has been validated with the experimental data in the literature and are also compared with a previous 1D model. The polarization curves show the voltage output against current density, lifetime is evaluated using a 10% voltage reduction criterion at the current density 0.6 A/cm2.An improved ECSA degradation model with variable load levels increases the lifetime of the ferry in Case 5 from 5500 hours to 7500 hours. Load cycling and idling cause the most severe degradation, but the impact can be reduced by a hybrid system with battery supplement and onshore charging. The lifetime of the ferry in Case 5 has been significantly further improved from 7500 hours to 22500 hours, which is comparable to the 20000-hour lifetime of commercial products for marine applications. Furthermore, membrane thickness effect analysis showed that fuel cells with thinner membranes (such as NR211) have better performance before degradation due to higher proton conductivity, but degrade faster during load cycling due to hydrogen crossover. The results of this research can be extended to help optimize fuel cell, stack and power system designs to avoid worst-case operating conditions and thereby limit fuel cell degradation. / Sjötransporter släpper ut cirka 3% av de globala växthusgaserna, International Maritime Organization (IMO) har som mål att minska sjöfartens utsläpp med 50 % jämfört med 2008 års nivåer. PEM-bränsleceller anses vara bland de mest lovande rena teknikerna för att minska koldioxidutsläppen i den maritima sektorn. En av utmaningarna för kommersiell användning av PEM-bränsleceller är deras begränsade hållbarhet. Syftet med denna avhandling var att bedöma de viktigaste nedbrytningsmekanismerna och driftsförhållandena för PEM-bränsleceller i marina applikationer, inklusive nedbrytning av membran och katalysatorskikt under tomgång, start-stopp-cykler och dynamiska belastningscykler, och att bygga en modell för att förutsäga livslängd.En semi-empirisk metod utvecklades för att utvärdera PEMFC:s livslängd genom en 2D COMSOL-modell. Modellen tar hänsyn till de empiriska sambanden för membrankonduktivitetsförlust och den elektrokemisk ytareans (ECSA) sönderfall som funktioner av cyklingstal, åldrandeprocess och tomgångstid. 2D-modellen har validerats med experimentella data i litteraturen och jämförs även med en tidigare 1D-modell. Polarisationskurvorna visar utspänningen mot strömtätheten, livslängden utvärderas med ett 10 % spänningsreduktionskriterium vid strömtätheten 0.6 A/cm2.En förbättrad modell för nedbrytning av elektrokemisk yta med varierande lastnivåer ökar färjans livslängd i fall 5 från 5500 timmar till 7500 timmar. Lastcykling och tomgång orsakar den allvarligaste försämringen, men påverkan kan minskas genom ett hybridsystem med batteritillägg och landladdning. Färjans livslängd i fall 5 har förbättrats avsevärt ytterligare från 7500 timmar till 22500 timmar, vilket är jämförbart med 20000 timmars livslängd för kommersiella produkter för marina applikationer. Vidare visade membrantjocklekseffektanalys att bränsleceller med tunnare membran (som NR211) har bättre prestanda före nedbrytning på grund av högre protonledningsförmåga, men bryts ned snabbare under belastningscykler på grund av väteövergång. Resultaten av denna forskning kan utökas för att hjälpa till att optimera designen av bränsleceller, stack och kraftsystem för att undvika värsta driftsförhållanden och därigenom begränsa nedbrytningen av bränsleceller.

In unserem alltäglichen Leben nehmen Kunststoffe eine immer größere Rolle ein. Die organische Struktur dieser Materialien bedingt die Brennbarkeit derselbigen und birgt somit eine Gefahr, die allgegenwärtig ist. Flammschutz von Polymeren ist daher eine wichtige Eigenschaft. Der Markt an Flammschutzadditiven ist bereits sehr breit gefächert. Allerdings gibt es nur wenig Studien, die systematisch Struktur und Flammschutzwirkung betrachten. So war es das Ziel dieser Arbeit, durch die Untersuchung zweier systematisch variierter Polymergruppen Struktur-Eigenschafts-Beziehungen zu entwicklen, die das Verständnis von Flammschutzadditiven erweitern. Die erste Gruppe bestand aus Polyestern mit einem gleichbleibenden Polymerrückrat an dem phosphorhaltige Seitenketten systematisch variiert wurden. In der zweiten Gruppe wurde das Polymergrundgerüst bei gleichbleibendem Substituenten variiert. Die Strukturen wurden umfassend hinsichtlich ihres Abbaus untersucht, so das durch Korrelation von Abbauverhalten und erarbeiteten Abbaumechanismen Zusammenhänge zwischen der nativen Polymerstruktur und dem Flammschutzverhalten gefunden werden konnten. Es lässt sich nachweisen, dass das Hauptabbaumaximum fast vollständig durch die Polymergrundkette dirigiert wird. Der Substituent hat wenig Einflauss darauf, womit sich die Möglichkeit ergibt Flammschutzadditive gezielt and das Abbaumaximum des zu schützenden Matrixpolymers anzupassen. Die strukturelle Veränderung des phosphorhaltigen Substituenten hingegen ermöglich es das Flammschutzadditv in seiner Wirkungsweise, also Aktivität in der Gasphase oder kondensierten Phase, anzupassen. Sehr wesentlich, besonders mit Blick auf die Rückstandbildung, ist das Zusammenspiel zwischen Substituent und Polymerrückgrat. Bei geeigneter Wahl aliphatischer und aromatischer Anteile lassen sich so Flammschutzadditive herstellen, die einerseits gut zu verarbeiten sind, andererseits aber auch einen möglichst hohen Rückstand erzeugen. Mit Kenntnis dieser Struktur-Eigenschafts-Beziehungen ist es zukünftig möglich, polymere Flammschutzadditive zielgerichteter zu entwickeln. So lässt sich das Additiv in seiner Wirkung nicht nur an das Matrixpolymer anpassen, sondern auch an die primären Brandgefahren in dessen Endanwendung. Eine Under-the-hood-Anwendung im Automobilbau fordert andere Flammschutzeigenschaften als die Verwendung im häuslichen Küchenbedarf.