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Organohalogen contaminants in wildlife from the Yangtze River Delta : Development of methods and assessments of legacy and emerging persistent organic pollutantsYin, Ge January 2016 (has links)
Rapid economic development has occurred during the past few decades in China with the Yangtze River Delta (YRD) area as one of the most progressive areas. The urbanization, industrialization, agricultural and aquaculture activities result in extensive production and application of chemicals. Organohalogen contaminants (OHCs) have been widely used as i.e. pesticides, flame retardants and plasticizers. They are persistent, bioaccumulative and pose a potential threat to ecosystem and human health. However, limited research has been conducted in the YRD with respect to chemicals environmental exposure. The main objective of this thesis is to investigate the contamination level, distribution pattern and sources of OHCs in the YRD. Wildlife from different habitats are used to indicate the environmental pollution situation, and evaluate selected matrices for use in long term biomonitoring to determine the environmental stress the contamination may cause. In addition, a method is developed for dicofol analysis. Moreover, a specific effort is made to introduce statistic power analysis to assist in optimal sampling design. The thesis results show extensive contamination of OHCs in wildlife in the YRD. The occurrences of high concentrations of chlorinated paraffins (CPs) are reported in wildlife, in particular in terrestrial species, (i.e. short-tailed mamushi snake and peregrine falcon). Impurities and byproducts of pentachlorophenol products, i.e. polychlorinated diphenyl ethers (PCDEs) and hydroxylated polychlorinated diphenyl ethers (OH-PCDEs) are identified and reported for the first time in eggs from black-crowned night heron and whiskered tern. High concentrations of octachlorodibenzo-p-dioxin (OCDD) are determined in these samples. The toxic equivalents (TEQs) of polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzofurans (PCDFs) are at mean levels of 300 and 520 pg TEQ g-1lw (WHO2005 TEQ) in eggs from the two bird species, respectively. This is two orders of magnitude higher than European Union (EU) regulation limit in chicken eggs. Also, a novel pattern of polychlorinated biphenyls (PCBs) with octa- to decaCBs, contributing to as much as 20% of total PCBs therein, are reported in birds. The legacy POPs shows a common characteristic with relatively high level of organochlorine pesticides (i.e. DDT, hexacyclohexanes (HCHs) and Mirex), indicating historic applications. In contrast, rather low concentrations are shown of industrial chemicals such as PCBs and polybrominated diphenyl ethers (PBDEs). A refined and improved analytical method is developed to separate dicofol from its major decomposition compound, 4,4’-dichlorobenzophenone. Hence dicofol is possible to assess as such. Statistic power analysis demonstrates that sampling of sedentary species should be consistently spread over a larger area to monitor temporal trends of contaminants in a robust manner. The results presented in this thesis show high CPs and OCDD concentrations in wildlife. The levels and patterns of OHCs in YRD differ from other well studied areas of the world. This is likely due to the extensive production and use of chemicals in the YRD. The results strongly signal the need of research biomonitoring programs that meet the current situation of the YRD. Such programs will contribute to the management of chemicals and environment in YRD, with the potential to grow into the human health sector, and to expand to China as a whole. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Submitted. Paper 6: Manuscript.</p><p> </p>
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Modelování závislosti biodegradací chlorovaných uhlovodíků na změně teploty a oxidačně-redukčních podmínkách v ATES systému / Modelling dependence of chlorinated hydrocarbons biodegradation on changes of temperature and redox conditions in ATES sytemsHavlíková, Barbora January 2013 (has links)
The Aquifer Thermal energy Storage (ATES) system is one of the most important techniques, that use the aquifer as an energy storage for heating and cooling the buildings. The operation of the ATES system is based on pumping the cold ground water into the buildings during the summer and then injecting the warmer water back into the aquifer. During the winter, the direction is reversed. Warm water is pumped to the buildings, where it serves for the heating system and then it is injected back into the aquifer. The ATES system has a main effect on the chemical composition of ground water, because of changes in the temperature of ground water, mixing of water from different redox zone and increasing of ground water flow in the neighbourhood of the wells of the ATES system. The modification in chemical composition and temperature could influence the behaviour of contaminants. If we want to install the ATES system into a contaminated aquifer, we have to know, if the ATES system would influence the behaviour of the contaminant plume positively or negatively. This study was made to increase the understanding of the dependence between changes of temperature and oxidation-reduction conditions in the ATES system and biodegradation of chlorinated hydrocarbons. In the first part, several scenarios were modelled...
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Kinetics of the Hydrodechlorination Reaction of Chlorinated Compounds on Palladium CatalystsChen, Nan 23 August 2003 (has links)
"
Hydrodechlorination is the reaction of a chlorinated organic compound (R-Cl) with hydrogen to form a carbon-hydrogen bond and HCl: R-Cl + H2 = R-H + HCl. This reaction is used in refrigerant manufacturing, industrial by-product reclamation and waste management. These practical applications require in-depth understanding of hydrodechlorination reaction. In this research work, we studied four families of chlorinated compounds; CF3CF3-xClx(x=1-3), CH4-xClx (x=1-4), CF4-xClx (x=1-4) and dichloropropanes (1,1-, 1,2-, 1,3-, 2,2-), on supported palladium catalysts to create a theory capable of predicting the hydrodechlorination rate on chlorinated compounds and to explore the reaction mechanism.
A possible set of elementary reaction steps of hydrodechlorination reaction was proposed from our kinetics study of all these compounds. In this set of reaction steps, the irreversible scission of the first C-Cl bond in a chlorinated compound was proposed to be the rate-determining step; gas phase H2 and HCl were suggested to be in equilibrium with surface H and Cl species; adsorbed Cl was assumed to be the most abundant surface intermediate. The overall rate of hydrodechlorination reaction could be derived from these reaction steps as r=k'[R-Cl]/(1+K'[HCl]/[H2]0.5). In this rate equation, k'is the product of the adsorption equilibrium constant of the chlorinated compound on catalyst surface times the rate constant for the scission of the first C-Cl bond scission step, and K'is the square root of the equilibrium constant for the equilibrium between H2, HCl and their corresponding surface species: 2HCl + 2* = H2 + 2Cl*.
The hydrodechlorination reaction of CF3CFCl2 was performed in the presence of H37Cl to study the reversibility of C-Cl bond scission, and the removal of the first Cl atom from CF3CFCl2 was found to be an irreversible step. Hydrodechlorination experiments of CF3CFCl2 with D2 and HCl mixture revealed that D2 and HCl were in equilibrium with surface adsorbed hydrogen and chlorine during reaction. The forward rate and reverse rate of this equilibrium were at least 400 times higher than the overall hydrodechlorination rate. This result supported the assumption of equilibrium for 2HCl + 2* = H2 + 2Cl*. Additionally, the activation energy for the rate determining step was extracted from hydrodechlorination reaction kinetics results of CH4-xClx (x=1-4), CF4-xClx (x=1-4) and dichloropropanes (1,1-, 1,2-, 1,3-, 2,2-) compounds. It was found that for each of the series compounds, a linear relationship existed between C-Cl bond scission activation energy and gas phase C-Cl bond strength. This observation corroborates our assumption that the removal of the first Cl atom from a chlorinated compound is the rate-determining step in the hydrodechlorination reaction. Thus, all kinetic and isotope experimental results obtained from this study are consistent with the proposed reaction steps for the chlorinated compounds tested. This set of reaction steps can also be used to predict the hydrodechlorination reaction rate of a chlorinated compound, once its gas phase C-Cl bond energy is calculated and the turnover rate of a reference chlorinated compound with similar structure is known.
Some work has been done to study hydrodechlorination reaction steps and reaction intermediates beyond the rate-limiting step. Isotope tracing experiments with D2 indicated that CH3-, CH2- groups adjacent to a C-Cl bond could undergo deuterium exchange. The study of reactions steps using ab initio methods, including calculation of rate constants, is also under way. Calculations for the CH4-xClx (x=1-4) family showed that the heat of adsorption and C-Cl bond dissociation energy on a Pd surface were linearly related to their gas phase C-Cl bond strength."
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On-site Wastewater Treatment and Reuse Using Recirculatory Evapotranspiration Channels in Regional QueenslandKele, Benjamin Mark, b.kele@cqu.edu.au January 2005 (has links)
The Central Queensland University developed an on-site wastewater treatment and
reuse technology. Septic tanks were used for primary treatment and the discharged
effluent was then pumped though a series of contained channels. The channels were
designed to be a modified evapotranspiration trench; they were comprised of an
aggregate layer and a soil layer in which were planted a variety of plants. The
aggregate and the soil provided physical filtration, the microorganisms within the
effluent, aggregate and soil provided nutrient reuse and transformation and the
plants also used the nutrients and reused the treated effluent through
evapotranspiration. Any effluent that was not transpired was returned to a holding
tank and pumped through the evapotranspiration again. The treatment technology
was assessed in relation to its ability to treat effluent in a sustainable manner. The
water and soil was examined for concentrations of nutrients, heavy metals, salts,
sodium, and organic carbon %. The pH, temperature and number of colony forming
units of certain microorganism potential pathogens were also inspected in the soil
and the water. The plants grown within the evapotranspiration channels were
assessed in regards to their health, water usage, and in some cases potential
pathogens on fruit. The infrastructure that was used to construct the wastewater
treatment and reuse system was also evaluated in regards to reliability and
maintenance. Certain limiting factors, in particular sodicity and salinity were
identified, but the trial was successful and a sustainable form of on-site wastewater
treatment and reuse technology was developed.
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Application of two dimensional compound specific carbon-chlorine isotope analyses for degradation monitoring and assessment of organic pollutants in contaminated soil and groundwaterWiegert, Charline January 2013 (has links)
Nearly 250,000 sites with past and present potentially polluting activities need urgent remediation within Europe. Major pollutants include organochlorines (OCls), e.g. chlorinated ethenes (CEs) and hexachlorocyclohexanes (HCHs), mainly used as industrial solvents and pesticides, respectively. Due to improper handling and disposal, OCls contaminants are present in the soil or groundwater surrounding sites, where they have been produced or used. CEs and HCHs can undergo degradation by microorganisms indigenous to the soil or groundwater. Therefore natural attenuation (NA), relying on the in situ biodegradation of pollutants, is considered as a cost effective remediation strategy, yet it requires accurate monitoring methods. Compound specific isotope analysis (CSIA) is a powerful tool to provide information on the extent of degradation and, when combining two isotope systems (2D-CSIA), such as carbon (δ13C) and chlorine (δ37Cl), on reaction mechanisms. The diagnostic reaction-specific isotope enrichment factors (εC and εCl) were determined in laboratory experiments for the anaerobic degradation of PCE, TCE (Paper II) and α-HCH (Paper III) by mixed bacterial cultures enriched from CEs and HCHs contaminated sites, respectively. The related mechanism-specific εCl/εC ratios were calculated as 0.35 ± 0.11 (PCE), 0.37 ± 0.11 (TCE) and 0.52 ± 0.23 (α-HCH). These values are smaller than previously reported values for pure cultures. This is explained by the microbial community composition changes observed during degradation of PCE and α-HCH, which also reflect the variability of the microbial community at the field level. Furthermore, εCl/εC ratio might be bacteria specific. These values allowed the estimation of the extent of contaminant degradation at the respective study sites (Paper III and IV). Application of both isotope systems (δ13C and δ37Cl) led to comparable estimates. However the choice of representative ε values is crucial for an accurate assessment. These studies show that CSIA is useful to quantify in situ degradation of OCls contaminants and identify reaction pathways, by combining δ13C and δ37Cl. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.</p>
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Effects of Leaving Group Ability and Microstructure on the Reactivity of Halogenated Poly(isobutylene-co-isoprene)MCNEISH, JOANNE 03 October 2011 (has links)
Halogenation of poly(isobutylene-co-isoprene) (IIR) increases its reactivity towards sulphur and other nucleophiles. Currently brominated (BIIR) and chlorinated (CIIR) derivatives are commercially available; however, an iodinated derivative has been briefly investigated. The effects of leaving group ability and microstructure on the reactivity of halogenated poly(isobutylene-co-isoprene) were studied to put iodobutyl rubber reactivity into context and to compare existing commercial products to their isomeric derivatives.
Polymers containing halomethyl (r-CIIR, r-BIIR, r-IIIR) isomers of butyl rubber were prepared from as-received BIIR to compare the effect of leaving group on thermal stability and reactivity towards nucleophilic substitution. The polymer containing (E,Z)-endo-iodomethyl isomers (r-IIIR) readily underwent nucleophilic substitution at low temperatures; however, it was sensitive towards dehydrohalogenation at temperatures above 65⁰C. At temperatures between 100⁰C and 135⁰C, the bromomethyl derivative (r-BIIR) demonstrated the best balance between reactivity toward nucleophilic substitution and dehydrohalogenation. Exceptional thermal stability at temperatures up to 190⁰C was displayed by the chloromethyl derivative (r-CIIR); however, it was unreactive at low temperatures towards certain nucleophiles. This lack of reactivity shown by r-CIIR was not consistent with all nucleophiles, as reaction dynamics with TBAAc display its variable reactivity towards nucleophilic substitution with results parallel to those of r-BIIR.
Exo-methylene allylic halides (Exo-Br, Exo-Cl) and (E,Z)-endo-halomethyl (r-BIIR, r-CIIR) isomers were vulcanized with sulphur to determine the effect of microstructure on reactivity. Results showed a clear effect of microstructure on the ability to cure with sulphur. While the Exo-Cl isomer has no ability to cure, when rearranged to its (E,Z)-endo-chloromethyl isomer curing occurs readily. Both the Exo-Cl and (E,Z)-endo-bromomethyl isomers readily vulcanize in the presence of sulphur, however Exo-Br cures to a greater extent. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-09-30 12:55:25.665
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Comportement de la mousse en milieu poreux pour confiner une source de pollution : potentialités, contraintes et démonstration en site réel / Foam behavior in porous media to confine a source zone of contaminant : potentialities, constraints and field demonstrationPortois, Clément 11 January 2018 (has links)
La présence de Composés Organiques Halogénés Volatils (COHV) dans les eaux souterraines est particulièrement problématique car celle-ci peut les contaminer pendant des dizaines d’années. Le traitement de ces sites, dont les pollutions sont souvent mixtes et complexes, nécessite de développer des techniques fiables. Particulièrement dans le contexte d’un aquifère hétérogène, les techniques classiques souffrent du faible potentiel de balayage de la pollution par les agents remédiant. La génération de mousse in situ est une technique de dépollution innovante permettant de contrôler la mobilité de ces agents. La démarche générale du travail de thèse porte sur le développement de l’injection de mousse et son applicabilité dans le contexte d’un site industriel en activité contaminé par des solvants chlorés. L’originalité de ce travail porte sur l’utilisation de la mousse comme agent confinant (hydrauliquement) d’une zone source au sein même de l’usine. Le premier objectif de cette thèse consiste en la définition de l’origine de la pollution et des processus responsables du transport des composés dissous dans un système aquifère multicouche et hétérogène. Dans ce cadre, un modèle de transport en 3 dimensions a été développé et contraint à partir de données géologiques (structure 3D), hydrogéologiques (piézométrie, mesure de vitesse), et chimiques (solvant chlorés et ions majeurs). Cette combinaison d’approches a eu un impact réel sur la compréhension de la dynamique hydrogéologique du système souterrain présent au droit du site d’étude, et a permis de définir la zone d’injection de mousse. En parallèle des travaux de caractérisation du site, un travail expérimental en laboratoire a permis de définir les mécanismes à l’origine de la réduction de la perméabilité relative à l’eau par l’injection de mousse. Au travers d’une approche multi échelle, ces travaux ont notamment permis de (i) définir une formulation (concentrations en tensio-actifs et composition) et les paramètres d’injection (qualité de mousse, débit d’injection, mode d’injection) pour générer une mousse favorable à la réduction de la saturation en eau (colonne 1D). Cette baisse de saturation ayant conduit à une réduction de la perméabilité à l’eau d’un facteur supérieur à 100. (ii) D’estimer le comportement de la mousse le long d’un profil d’injection et son impact sur la réduction de la saturation en eau à quelques centimètres d’un point d’injection (pilote 2D décimétrique). (iii) De vérifier l’applicabilité en 3D du système d’injection développé et de suivre les évolutions de l’impact de la mousse dans un aquifère (essai sur un piézomètre réel). Enfin, un test d’injection de mousse en continu pendant 96h au droit de la zone source du site industriel contaminé a été réalisé. La réalisation d’un essai de pompage (post injection) au centre de la zone confinée, couplé à des mesures de flux de polluant (pré et post injection) et implémenté dans un modèle 2D, ont permis de mettre en évidence l’impact réel de la mousse sur un rayon supérieur à 2m avec une réduction du flux de polluant en aval hydraulique d’un facteur 4,5. Les différents travaux de laboratoire et de modélisation mettent en évidence les avancées et limites de la technique développée et permettent de proposer des voies d’amélioration. / The presence of Volatile Organic Compounds (VOCs) in groundwater is particularly problematic because it can contaminate them for decades. The treatment of these sites, whose pollution is often mixed and complex, requires the development of reliable techniques. Particularly in the context of a heterogeneous aquifer, conventional techniques suffer from the low potential for pollution sweeping by remedying agents. In situ foam generation is an innovative technique to control the mobility of these agents. The general approach of the thesis concerns the development of foam injection and its applicability. in the context of an industrial site in activity contaminated by chlorinated solvents. The originality of this work concerns the use of foam as a confining agent (hydraulically) of a source zone within the plant itself. The first objective of this thesis is to define the origin of pollution and the processes responsible for the transport of dissolved compounds in a multilayered and heterogeneous aquifer system. In this context, a 3-dimensional transport model has been developed and constrained based on geological data (3D structure), hydrogeological data (piezometry, groundwater velocity measurement), and chemical data (chlorinated solvent and major ions). The combination of these approaches had a real impact on the understanding of the hydrogeological dynamics of the underground system present at the study site, and allowed us to define the foam injection zone. In parallel with site characterization, experimental work in laboratory allows to define the mechanisms responsible for reducing the water-relative permeability by injecting foam. Through a multi-scale approach, we (i) define a formulation (surfactant concentrations and composition) and injection parameters (foam quality, injection rate, injection mode ) to generate a foam favorable to the reduction of water saturation (column 1D). This saturation decrease led to a reduction of the water relative permeability by a factor greater than 100. (ii) Estimate the behavior of the foam along an injection profile and its impact on the reduction saturation in water a few centimeters from an injection point (2D decimetric pilot). (iii) Verify the 3D applicability of the developed injection system and to follow the evolutions of the impact of the foam in an aquifer (test on a real piezometer). Finally, a continuous foam injection test during 96 hours at the source zone of the contaminated industrial site was carried out. Conducting a pumping test (post injection) in the center of the confined zone, coupled with contaminant fluxes measurements (pre and post injection) and implemented in a 2D model, highlighted the real impact of the injected foam over a radius greater than 2m with a reduction of the flow of pollutant downstream by a factor 4.5. The various laboratory and modeling work highlight the advances and limitations of the developed technique and make it possible to propose ways of improvement.
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Uso de processos oxidativos avançados e ferro elementar na remediação de agua subterranea contendo compostos organoclorados / Use of advanced oxidation process and zero valent ironinremediation of groundwater containing chlorinated compoundsArruda, Tatiana Langbeck de 11 April 2005 (has links)
Orientador: Wilson de Figueiredo Jardim / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T13:56:31Z (GMT). No. of bitstreams: 1
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Previous issue date: 2005 / Mestrado / Quimica Analitica / Mestre em Química
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Bacterial adaptation to the chlorinated compounds / Adaptation bactérienne aux composés chlorésDavid, Maude 11 December 2009 (has links)
Le travail présenté dans cette thèse porte sur l'adaptation bactérienne aux molécules chlorées, tant au niveau des ressources génétiques nécessaires à la mise en place des gênes de dégradation qu'au niveau de la structure de la communauté microbienne observée durant la dégradation de ces composés. La première partie de ce document est une bibliographie qui se focalise sur les mécanismes développés par les bactéries pour répondre aux stress environnementaux, et sur les possibles origines des gènes responsables des premières étapes de dégradation des composés chlorés : les dehalogenases (qui réalisent les étapes de déchloration). Le deuxième chapitre de cette thèse porte sur des essais expérimentaux de remodelage génétique, dans le but de valider les hypothèses présentées lors de la bibliographie quant aux mécanismes qui ont pu conduire à la génération de nouveaux gênes de dégradation. Ces remodelages in vitro et in vivo ont été effectués en utilisant les gènes linB et dhaA. Le chapitre suivant examine la structure de la communauté bactérienne lors de la dégradation réductive du tetrachloroéthylène (PCE). Pour cette étude, des outils de biologie moléculaire, plus spécifiquement des puces phylogénétiques, ont été utilisés pour étudier la structure de la communauté microbienne depuis l'introduction du polluant jusqu'à sa dégradation. Afin d'élucider les fonctions métaboliques qui peuvent être corrélées avec la dégradation du PCE, les résultats des puces phylogénétiques ont été comparés avec un suivi chimique des métabolites de dégradation de ce composé, lors d'une étude en microcosmes. L'objectif du dernier chapitre de la thèse a été de relier la structure de la communauté microbienne avec la cinétique de dégradation des composés chimiques étudiés. Pour cela, une étude globale comportant à la fois un suivi chimique des métabolites de dégradation, une quantification des gènes de dégradation impliqués dans la déchloration réductive du PCE ainsi que l'étude de la structure de la communauté microbienne ont été mis en place. Cette étude a permis de corréler les conditions environnementales nécessaires à la déchloration et la communauté microbienne associée avec l'expression des déhalogénases quantifiées. En résumé, cette thèse explore à la fois les mécanismes mis en place par les bactéries pour dégrader ces composés polluants et la structure de la communauté bactérienne durant la dégradation de ce polluant. Comprendre ces deux étapes dans l'adaptation bactérienne peut contribuer à améliorer l'utilisation des capacités bactériennes utilisées en bioremédiation. / This thesis concerns the bacterial adaptation to the chlorinated compounds at both the gene level and the microbial community level. The bibliography will focus on the adaptation mechanisms developed by bacteria to respond to environmental stresses and on the possible origins of the genes responsible for the first steps of chlorinated compound degradation, those encoding for the dehalogenases, which perform the dechlorination or chlorine removal step. The second chapter of the thesis consists of an experimental exploration of the gene shuffling hypothesis presented in the bibliography, using linB and dhaA genes. The next chapter examines the bacterial community structure in relation to compound degradation using the reductive dechlorination of tetrachloroethylene. For this study, molecular biology tools, specifically phylochip microarrays were used to examine bacterial community structure from the moment of pollutant introduction to the environment and during bioremediation. In order to elucidate the metabolic functions, which correlate the PCE degradation, phylogenetic results were compared with functional genes in the microcosms studied. The last chapter of this global study on chlorinated compound degradation genes was to link the microbial community structure kinetics with the chemical degradation kinetics. In order to evaluate the molecular biological parameters of the microbial community, all the genes known to be involved in the entire pathway of PCE reductive dechlorination were quantified. This global study, incorporating chemical monitoring, dehalogenase quantification and microbial community structure, produced correlations between the environmental conditions necessary for dechlorination and the microbial community associated with dehalogenase expression. In summary, both the mechanisms implemented by the bacteria to degrade this compound pollutant and the bacterial community structure during the pollutant degradation were addressed. Improving the understanding of these two steps in bacterial adaptation can contribute to the understanding of bacterial and environmental cleanup capabilities.
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Thermobonded 3D nonwoven wool structuresNassar, Khaled Mansour Abd el hafez January 2010 (has links)
The aims of this study were to form uncompressed thermobonded 3D wool nonwoven shell structures in one continuous process, and to study the controlling factors that govern this process. Lack of bonding between wool fibres and between wool and thermoplastic fibres was attributed to the wool fibre's low surface energy because of the lipids on the outer surface of wool fibres (epicuticle). To overcome this problem, three different surface treatments were investigated; chlorination, Hercosett and plasma. The purpose of these treatments was to raise the surface energy of wool fibres by bond scission and the introduction of new functional polar groups and ablation of the outer lipid layer or membrane. For thermobonding with wool fibres, low melting nylon fibres were chosen because of their high polarity and chemical compatibility with wool fibres. SEM, BSM and ESEM imaging techniques as well as tensile strength testing for single fibres, pair bonded samples and 3D nonwoven shells were used to assess the samples. Results have shown that it is possible to thermobond wool and nylon fibres as 3D shell structures, given that wool fibres are treated appropriately and the bonding temperature is controlled properly. Moreover, it has been found that, for pair bonded samples, the wrapping angle and the bonding angle have significant effects on the tensile strength and number of bonding points. Hercosett treated wool fibres yielded the strongest bonds with nylon fibres followed by plasma, chlorinated and untreated fibres.
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