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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Konenäköä soveltavan kuituanalysaattorin ja virtauskenttäfraktionaattorin mittausten yhteydet kuumahierteen paperiteknisiin ominaisuuksiin:kokeellinen tutkimus

Tiikkaja, E. (Esa) 23 November 2007 (has links)
Abstract In TMP quality control, on-line control applications are the goal. Reliable, versatile systems are needed for this task. Various model-based systems have been developed but their performance has not always been good enough. This study evaluated the applicability of fibre analysers utilising image analysis techniques for TMP quality control. In addition to the standard measurement results of these analysers, the values of primary measurements and the fibre images obtained with these analysers were studied. Two sets of test samples were used. The first set contained 24 samples from trials at a Scandinavian TMP plant, and this set made up the the main part of the test material. The other series was a set of 13 samples obtained from another TMP plant during a short testing period that took place between normal operation runs. In this set the quality variations were understandably smaller. Fibre size analyses were made with an optical analyser that applies image analysis techniques on single fibres. The effects of fibre length, fibre width, cell wall thickness, coarseness, fines content, fibre curl and external fibrillation on the quality potential of TMP were evaluated. Both the measured averages and the values of single fibres were used in the evaluation. A tube flow fractionator was used to evaluate fibre properties during the fractionation process. The results of the fractionation as well as the original measurement signals were used in the evaluation. Both analysers were set to save images of fibres during the analyses. These images were later analysed by using standard image analysis procedures, in order to obtain additional information of the fibres. Correlation analysis and principal component analysis were used as tools to find out dependencies between fibre properties and pulp quality. Fibre curl and fibre width were found to be the most promising fibre features for use in TMP quality evaluation with optical fibre analysers. These variables accounted for more than 70% of the variations in most of the evaluated TMP quality variables. In the tube flow fractionator results, the signals of the long fibre fraction were also able to explain over 70% of the variations in drainage, bonding strength, roughness, and porosity. The values of the fibre size analyser, together with the measurements and features derived from the images of the tube flow fractionator, provided significant additional information for quality estimation. The most important variables in TMP quality calculation were fibre curl, fibre width, and the tube flow fractionator signals for the long fibre fraction. Both the on-line analysers using image analysis for fibre measurements, and the tube flow to fractionate pulp samples before measurement, are able to provide reliable and relevant information for TMP quality control. / Tiivistelmä Kuumahierteen laadunvalvonnan tavoitteena on luotettava ja monipuolinen on-line-mittauksiin perustuva laadunohjaus. Tehtävään on kehitetty mallipohjaisia järjestelmiä, mutta ne eivät ole olleet aina riittävän suorituskykyisiä. Tässä tutkimuksessa selvitettiin konenäköön perustuvien kuituanalysaattoreiden soveltuvuutta kuumahierteen laadunohjauksen tarpeisiin. Sekä analysaattoreiden tuottamaa valmista mittaustietoa, että niiden kuitukohtaisia mittaustuloksia ja kuvamateriaalia tutkittiin. Tutkimuksessa käsiteltiin kahta erillistä koesarjaa. Ensimmäinen sarja sisälsi 24 koepistettä erään TMP-laitoksen koeajosta. Nämä näytteet muodostivat pääosan testimateriaalista. Toinen sarja koostui erään toisen tehtaan tuotantomassoista otetuista 13 näytepisteestä. Tässä sarjassa laatumuutokset olivat huomattavasti vähäisempiä kuin edellisessä sarjassa. Kuidunkokoanalyysit tehtiin konenäköä soveltavalla, yksittäisiä kuituja mittaavalla laitteella. Tutkimuksessa selvitettiin kuidunpituuden, kuidun leveyden, seinämävahvuuden, pituusmassan, hienoaineen, kuidun kiharuuden ja kuidun ulkoisen fibrillaation vaikutusta kuumahierteen laatuun. Näytekohtaisten keskiarvojen lisäksi myös kuitukohtaiset tiedot analysoitiin. Virtauskenttäfraktionaattorilla tutkittiin kuitujen optisia ominaisuuksia lajittelutapahtuman aikana. Mittaustuloksista käsiteltiin sekä valmiit jaetulokset että mittaussignaalien jakautumat lajittelutapahtuman ajalta. Molempien laitteiden tallettamia kuitukuvia analysoitiin niiden mahdollisesti sisältämän mutta vielä hyödyntämättömän informaation selvittämiseksi. Analyysityökaluina käytettiin korrelaatioanalyysiä ja pääkomponenttianalyysiä. Konenäköön perustuvan kuituanalysaattorin antamista tuloksista kuidun kiharuus ja kuidun leveys osoittautuivat luotettavimmiksi laatupotentiaalin indikaattoreiksi. Selitysasteet suurimmalle osalle mitattuja massan lujuus- ja arkkiominaisuuksia olivat yli 70 %. Virtauskenttäfraktionaattorin tuloksissa pitkäkuituosuutta vastaavat signaalijakeet antoivat samaten yli 70 %:n selitysasteet suotautuvuuden, sidoslujuuden, karheuden ja huokoisuuden arvioinnille. Kuituanalysaattorin kuidunkokoarvojen ja virtauskenttäfraktionaattorin signaalijakeiden ja -jakautuma-arvojen sekä kuvapiirteiden avulla lasketut kahden muuttujan mallit toivat useimpien käsiteltyjen laatumuuttujien estimaattien selitysarvoihin merkittävää parannusta. Tärkeimmät muuttujat kuumahierteen laatupotentiaalin arvioinnissa olivat kuidun kiharuus ja kuidun leveys sekä virtauskenttäfraktionaattorin signaalijakeet. Konenäköä soveltava kuituanalysaattori ja virtauskenttäfraktionaattori soveltuvat hyvin kuumahierteen laadun valvonta- ja ohjausmallin pohjaksi.
2

The effect of water chemistry and fibre-size distribution on dissolved air flotation efficiency

Sjölander, Anna January 2009 (has links)
<p>The purpose of this diploma work was to investigate the problem of insufficient fibre recovery in the dissolved air flotation-cell at the new thermomechanical pulping-line at Braviken Paper Mill. An investigation of the effect of process parameters on the removal efficiency in the micro-flotation process was undertaken.</p><p>The experiments were carried out for two setups at the Noss pilot plant with a small-scale flotation unit. Factorial design helped plan the experiments and four factors were controlled; temperature, fibre-size distribution, water quality and feed concentration. Three samples, feed, overflow and filtrate, were taken from each experiment and concentration measurements were made. The results were analyzed using the software MODDE.</p><p>The results from showed an influence from the fibre-size distribution. To see if the fibre-size distribution really had an effect on the results, follow-up experiments were carried out. These experiments showed no influence from temperature, fibre-size distribution or water quality. This concludes that none of those three factors influenced the results significantly.</p><p>Additional experiments were done to examine the influence from concentration and fibre-size distribution on the flotation efficiency and these showed an influence from the feed concentration. When increasing the feed concentration the efficiency of the flotation process decreased.</p>
3

The effect of water chemistry and fibre-size distribution on dissolved air flotation efficiency

Sjölander, Anna January 2009 (has links)
The purpose of this diploma work was to investigate the problem of insufficient fibre recovery in the dissolved air flotation-cell at the new thermomechanical pulping-line at Braviken Paper Mill. An investigation of the effect of process parameters on the removal efficiency in the micro-flotation process was undertaken. The experiments were carried out for two setups at the Noss pilot plant with a small-scale flotation unit. Factorial design helped plan the experiments and four factors were controlled; temperature, fibre-size distribution, water quality and feed concentration. Three samples, feed, overflow and filtrate, were taken from each experiment and concentration measurements were made. The results were analyzed using the software MODDE. The results from showed an influence from the fibre-size distribution. To see if the fibre-size distribution really had an effect on the results, follow-up experiments were carried out. These experiments showed no influence from temperature, fibre-size distribution or water quality. This concludes that none of those three factors influenced the results significantly. Additional experiments were done to examine the influence from concentration and fibre-size distribution on the flotation efficiency and these showed an influence from the feed concentration. When increasing the feed concentration the efficiency of the flotation process decreased.
4

Mechanical Pulp Based Nano-ligno-cellulose : Production, Characterisation and their Effect on Paper Properties

Osong, Sinke Henshaw January 2014 (has links)
Almost all research on biorefinery concepts are based on chemical pulping processes and ways of utilising lignin, hemicelluloses and extractives as well as a part of the remaining cellulose for production of nano materials in order to create more valuable products than today. Within the Forest as a Resource (FORE) research program at FSCN we are utilising the whole chain of unit processes from forestry to final products as paper and board, where the pulping process research focus on high yield process as TMP and CTMP. As these process solutions are preserving or only slightly changing the properties of the original wood polymers and extractives, the idea is to find high value adding products designed by nature. From an economic perspective, the production of nanocellulose from a chemical pulp is quite expensive as the pulp has to be either enzymatically (e.g. mono-component endoglucanase) pre-treated or chemically oxidised using the TEMPO (2,2,6,6 - tetramethyl-piperidine-1-oxil) - mediated oxidation method in order to make it possible to disrupt the fibres by means of homogenisation. In high yield pulping processes such as in TMP and CTMP, the idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nano-ligno-cellulose (NLC). The integration of a NLC unit process in a high yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and board grades. The intention of this research work was that, by using this concept, a knowledge base can be created so that it becomes possible to develop a low-cost production method for its implementation. In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenisation It seems possible to homogenise fine particles of thermo-mechanical pulp (1% w/v) to NLC. A correspond fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration. The objective presented in this work was to develop a methodology for producing mechanical pulp based NLC from fines fractions and to utilise this material as strength additives in paper and board grades. Laboratory sheets of CTMP and BKP, with addition of their respective NLC, were made in a Rapid Köthen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z-strength and other important mechanical properties for similar sheet densities. The characterisation of the particle size distribution of NLC is both important and challenging and the crill methodology developed at Innventia (former STFI) already during the 1980s was tested to see if it would be both fast and reliable enough. The crill measurement technique is based on the optical responses of a micro/nano particle suspension at two wavelengths of light; UV and IR. The crill value of TMP and CTMP based nano-ligno-cellulose were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time.
5

Mechanical Pulp-Based Nanocellulose : Processing and applications relating to paper and paperboard, composite films, and foams

Osong, Sinke Henshaw January 2016 (has links)
This thesis deals with processing of nanocellulose originating from pulps, with focus on mechanical pulp fibres and fines fractions. The nanocellulose materials produced within this research project were tested for different purposes ranging from strength additives in paper and paperboard products, via composite films to foam materials. TAPPI (Technical Association of Pulp &amp; Paper Industry) has recently suggested a standard terminology and nomenclature for nanocellulose materials (see paper I). In spite of that we have decided to use the terms nano-ligno-cellulose (NLC), microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC) and nanocellulose (NC) in this thesis . It is well-known that mainly chemical pulps are used as starting material in nanocellulose production. However, chemical pulps as bleached sulphite and bleached kraft are quite expensive. One more cost-effective alternative can be to use fibres or fines fractions from thermo-mechanical pulp (TMP) and chemi-thermomechanical pulp (CTMP).   In paper II-IV, fractionation has been used to obtain fines fractions that can easily be mechanically treated using homogenisation. The idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nanocellulose. The integration of a nanocellulose unit process in a high-yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and paperboard grades.   Paper III describes how to utilise the crill measurement technique as a tool for qualitative estimation of the amount of micro- and nano-material produced in a certain process. The crill values of TMP- and CTMP-based nanocelluloses were measured as a function of the homogenisation time. Results showed that the crill values of both TMP-NLC and CTMP-NLC correlated with the homogenisation time. In Paper V pretreating methods, hydrogen peroxide and TEMPO are evaluated. Crill measurement showed that hydrogen peroxide pretreatment (1% and 4%) and mechanical treatment time did not improve fibrillation efficiency as much as expected. However, for TEMPO-oxidised nanocelluloses, the crill value significantly increased with both the TEMPO chemical treatment and mechanical treatment time. In paper V-VII TEMPO-mediated oxidation systems (TEMPO/NaBr/NaClO) are applied to these fibres (CTMP and Sulphite pulp) in order to swell them so that it becomes easy to disrupt the fibres into nanofibres with mechanical treatment.   The demand for paperboard and other packaging materials are steadily increasing. Paper strength properties are crucial when the paperboard is to withstand high load. A solution that are investigated in papers IV and VI, is to use MFC as an alternative paper strength additive in papermaking. However, if one wish to target extremely higher strength improvement results, particularly for packaging paperboards, then it would be fair to use MFC or cationic starch (CS). In paper VI CS or TEMPO-based MFC was used to improve the strength properties of CTMP-based paperboard products. Results here indicate significant strength improvement with the use of different levels of CS (i.e., 20 and 10 kg t–1) and 5% MFC. The strengthening impact of 5% MFC was approximately equal to that of 10 kg t–1 of CS.   In paper VII, NFC and nanographite (NG) was used when producing composite films with enhanced sheet-resistance and mechanical properties. The films produced being quite stable, flexible, and bendable. Realising this concept of NFC-NG composite film would create new possibilities for technological advancement in the area of high-yield pulp technology.  Finally, in paper VIII, a new processing method for nanocellulose is introduced  where an organic acid (i.e., formic acid) is used. This eco-friendly approach has shown to be successful, a nanocellulose with a uniform size distribution has been produced. / <p>Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 5 och 7 inskickade, delarbete 6 och 8 manuskript.</p><p>At the time of the doctoral defence the following papers were unpublished: paper 5 and 7 submitted, paper 6 and 8 manuscripts.</p>
6

Análise do circuito de água em processo de fabricação de papel imprensa integrada com produção de pastas termomecânicas. / Analysis of the water circuit of an integrated newsprint and thermomechanical pulp manufacturing process.

Hamaguchi, Marcelo 10 September 2007 (has links)
A indústria de papel e celulose passa por constantes desafios para solucionar problemas relacionados ao alto consumo de água industrial. Uma alternativa é utilizar ferramentas como a Integração de Processos, onde é possível aplicar técnicas gráficas como o \"Water Pinch\" ou técnicas com programação matemática para otimizar o circuito de água. Para contribuir com o setor, as técnicas foram aplicadas no presente trabalho utilizando-se dados reais coletados em uma unidade produtora de polpa termomecânica e papel imprensa. Com os dados, um caso base em um simulador foi desenvolvido para iniciar a análise por Integração de Processos. A análise é baseada no aproveitamento das correntes de águas residuais em outras etapas do processo sob restrições na concentração limite de contaminantes, especificamente finos e sólidos dissolvidos. Diferentemente dos trabalhos apresentados na literatura que alegam que a solução encontrada trata-se de valores otimizados, os resultados mostram que os valores encontrados através da programação matemática e do método Pinch são teoricamente corretos, porém, quando novamente simuladas sob estas novas condições obtidas por Integração de Processos, as condições operacionais da unidade industrial mostram-se inadequadas. As concentrações limites de contaminantes previamente estabelecidos pelas técnicas utilizadas são frequentemente ultrapassadas nos resultados de recálculo por simulação, e portanto, as soluções de Integração de Processos devem ser corrigidas antes de implantação. Por isso, os valores previstos, por exemplo, de redução de consumo de até 38% no projeto realístico atinge o valor de 23%, o que ainda é um bom resultado. O trabalho ainda mostra que a programação matemática é eficaz e rápida para encontrar soluções com múltiplos contaminantes, enquanto o método Pinch é mais voltado para casos com contaminante simples. / The Pulp and Paper industry has constantly struggled to solve problems related to high water consumption. One alternative is to use tools like Process Integration, where graphical methods and mathematical programming can be applied to optimize the water circuit. To contribute to the Pulp and Paper sector, the methods were applied in the present work using real process data that have been collected in an integrated thermomechanical and newsprint mill. With these data, a base case simulation was developed to initiate the analysis by Process Integration. The analysis is based on residual water reuse in other process stages under propriety constraints like contaminants concentration limits, specifically the dissolved solids and fine fibers. Differently from works presented in the references that claim that solutions found are optimized values, the results of this work show that values found by mathematical programming and pinch method are theoretically correct, however, the operational conditions of the mill become inadequate when simulated under new conditions achieved by Process Integration. The concentration limits of contaminants previously established for the methods have their values frequently exceed after recalculation by simulation, and thus, the solutions by Process Integration must be corrected before using them. So, if the predicted value for reduction of fresh water consumption is, for example, 38%, in the realistic project this value will reach only 23%, which is still a good result. The work also shows that mathematical programming is efficient to find solutions when there are multiple contaminants, while pinch method is more adequate for those cases with single contaminant.
7

Análise do circuito de água em processo de fabricação de papel imprensa integrada com produção de pastas termomecânicas. / Analysis of the water circuit of an integrated newsprint and thermomechanical pulp manufacturing process.

Marcelo Hamaguchi 10 September 2007 (has links)
A indústria de papel e celulose passa por constantes desafios para solucionar problemas relacionados ao alto consumo de água industrial. Uma alternativa é utilizar ferramentas como a Integração de Processos, onde é possível aplicar técnicas gráficas como o \"Water Pinch\" ou técnicas com programação matemática para otimizar o circuito de água. Para contribuir com o setor, as técnicas foram aplicadas no presente trabalho utilizando-se dados reais coletados em uma unidade produtora de polpa termomecânica e papel imprensa. Com os dados, um caso base em um simulador foi desenvolvido para iniciar a análise por Integração de Processos. A análise é baseada no aproveitamento das correntes de águas residuais em outras etapas do processo sob restrições na concentração limite de contaminantes, especificamente finos e sólidos dissolvidos. Diferentemente dos trabalhos apresentados na literatura que alegam que a solução encontrada trata-se de valores otimizados, os resultados mostram que os valores encontrados através da programação matemática e do método Pinch são teoricamente corretos, porém, quando novamente simuladas sob estas novas condições obtidas por Integração de Processos, as condições operacionais da unidade industrial mostram-se inadequadas. As concentrações limites de contaminantes previamente estabelecidos pelas técnicas utilizadas são frequentemente ultrapassadas nos resultados de recálculo por simulação, e portanto, as soluções de Integração de Processos devem ser corrigidas antes de implantação. Por isso, os valores previstos, por exemplo, de redução de consumo de até 38% no projeto realístico atinge o valor de 23%, o que ainda é um bom resultado. O trabalho ainda mostra que a programação matemática é eficaz e rápida para encontrar soluções com múltiplos contaminantes, enquanto o método Pinch é mais voltado para casos com contaminante simples. / The Pulp and Paper industry has constantly struggled to solve problems related to high water consumption. One alternative is to use tools like Process Integration, where graphical methods and mathematical programming can be applied to optimize the water circuit. To contribute to the Pulp and Paper sector, the methods were applied in the present work using real process data that have been collected in an integrated thermomechanical and newsprint mill. With these data, a base case simulation was developed to initiate the analysis by Process Integration. The analysis is based on residual water reuse in other process stages under propriety constraints like contaminants concentration limits, specifically the dissolved solids and fine fibers. Differently from works presented in the references that claim that solutions found are optimized values, the results of this work show that values found by mathematical programming and pinch method are theoretically correct, however, the operational conditions of the mill become inadequate when simulated under new conditions achieved by Process Integration. The concentration limits of contaminants previously established for the methods have their values frequently exceed after recalculation by simulation, and thus, the solutions by Process Integration must be corrected before using them. So, if the predicted value for reduction of fresh water consumption is, for example, 38%, in the realistic project this value will reach only 23%, which is still a good result. The work also shows that mathematical programming is efficient to find solutions when there are multiple contaminants, while pinch method is more adequate for those cases with single contaminant.
8

The Influence of pH, Temperature and Number of Wash Steps on the Washing Efficiency of CTMP Pulp

Monlars, André January 2021 (has links)
In this report, the washing efficiency of chemi-thermomechanical pulp (CTMP) from Norway spruce (Picea abies) was investigated when adjusting the temperature and pH during washing as well as implementing different number of wash steps. Concurrent effects of having a high pH and temperature were also examined. CTMP pulp has many uses, one of which is for the manufacturing of packaging board. Lately, this end product has seen a precipitous increase due to the increasing demand of an environmentally friendly alternative within the food packaging sector. A notorious problem associated with all mechanical pulps is how extractives are to a large extent still present after the pulping process, especially unsaturated lipids which are subject to oxidation. This results in the formation of odorous aldehydes that can be easily transferred into the food product, thus contaminating it by altering the perception of taste and odor. This is a frequent problem faced by the status quo liquid board industry. Washing is thus employed late downstream to lower the final wood resin content. Here, available literature has been collated for some basic introductory subjects such as softwood anatomy, wood resin and structures. All of this is described with a focus on softwood, leading up to a thorough breakdown of P. abies. Mechanical pulping and relevant deresination methods for CTMP production are also described, including washing. The objective of this thesis is to evaluate the trends of the final resin concentration as the chosen parameters are altered during washing. The pulp was provided by Rottneros Mill and their industrial process was simulated by using a Büchner funnel for washing. A Soxhlet extractor was used for determining the final extractive contents. It was found that the implementation of additional wash steps reduced the final resin content (1–4 wash steps). The same was found with increasing temperature (60, 70, 80 and 90 °C). The implementation of a fourth wash step seemed to be more efficient at higher temperatures. No conclusions could be drawn from altering the pH due to scattered data points with high uncertainties (pH 7, 8 and 9). The results are limited in terms of significance and are also subject to bias. / I denna rapport undersöktes tvätteffektiviteten av kemitermomekanisk massa (CTMP, chemi-thermomechanical pulp) tillverkad från gran (Picea abies) och hur den påverkas vid justeringar av temperatur, pH och antal tvättsteg. Ytterligare undersöktes förekomsten av eventuella samverkande effekter vid högre temperatur och pH. CTMP-massa har många användningsområden, däribland vid produktion av vätskekartong. På sistone har efterfrågan av vätskekartong ökat markant som ett svar på en allt större strävan efter ett mer miljövänligt alternativ inom matförpackningssektorn. Ett välkänt problem associerat med mekanisk massatillverkning är den stora mängden exktraktivämnen som kvarhålls i den färdiga massan. En viss del av dessa extraktivämnen utgörs av fleromättade fetter vilket är benägna att genomgå oxidation. Detta leder i sin tur till bildandet av flyktiga aldehyder som kan föras vidare till matprodukten och ge dem förändrad smak och lukt; ett problem som dagens vätskekartongproducenter står inför. Tillgänglig litteratur har sammanställts, där en inledande teoridel beskriver koncept såsom anatomi, strukturer och extraktivämnen hos barrved. Teoridelen övergår därefter till att ge en mer detaljerad beskrivning av P. abies och dess extraktivinnehåll. Ytterligare beskrivs mekanisk massatillverkning över lag och metoder för att eliminera extraktivämnen under produktionen av CTMP-massa (inklusive tvättning). Syftet med detta examensarbete är att utvärdera de trender i den slutliga extraktivhalten då de valda parametrarna justeras under tvättning. Massan tillhandahölls av Rottneros Bruk och deras tvättningsprocess simulerades med hjälp av en Büchner-tratt. En Soxhlet-extraktor användes för att utvärdera den slutliga extraktivhalten. Det visade sig att vid varje insättning av ett ytterligare tvättsteg (1–4 tvättsteg) gav en lägre extraktivhalt hos CTMP-massan. Desamma gällde vid ökande temperatur (60, 70, 80 and 90 °C). Implementering av ett fjärde tvättsteg tycks vara mer effektivt vid högre temperaturer. Det kunde dock inte dras några slutsatser huruvida pH påverkade tvättningen då dessa mätvärden fick stor spridning med höga osäkerheter (pH 7, 8 och 9). Resultaten besitter begränsad signifikans och kan även ha blivit utsatta för bias.
9

Elaboration et évaluation biologique de nouveaux matériaux lignocellulosiques antibactériens / Elaboration and biological evaluation of new antibacterial lignocellulosic materials

Khaldi, Zineb 26 October 2018 (has links)
La contamination des surfaces par des bactéries et l’émergence de souches résistantes aux antimicrobiens sont des problèmes très préoccupants dans différents domaines tel que les domaines hospitalier et alimentaire. Cette contamination commence par l’adhésion de bactéries pathogènes sur une surface jusqu’à la formation de biofilms. Ces derniers contribuent à l’émergence de résistances de certaines souches bactériennes aux traitements conventionnels. Pour répondre à ces problèmes de contamination des surfaces, ces travaux de thèse portent sur le développement de nouveaux matériaux antibactériens à base de fibres de pâte à papier. Nous nous sommes intéressés, dans une première partie, à l’élaboration d’un papier antibactérien par le greffage, via un lien triazine, de deux composés d’huiles essentielles, le thymol et le carvacrol, connus pour leurs activités antibactériennes. L’évaluation microbiologique des matériaux élaborés, sur les deux souches bactériennes testées, E.coli et S.aureus, a montré un effet bactériostatique. Ces matériaux bloquent donc la croissance bactérienne empêchant ainsi la formation des biofilms. Une synergie entre le thymol et le carvacrol lorsqu’ils sont greffés sur les fibres de pâte à papier a également été montré. Dans une deuxième partie, notre étude s’est focalisée sur l’élaboration d’un papier antibactérien qui n’acquière son activité qu’après greffage et formation du motif actif « aryl-1,2,3-triazole ». Le greffage est réalisé par une réaction de « Click Chemistry », la cycloaddition de Huisguen catalysée par le cuivre I. Les tests antibactériens révèlent l’importance du substituant de l’aryle, l’influence du temps de contact et la pertinence d’utiliser des mélanges de matériaux. L’activité antibactérienne observée sur les fibres de la pâte thermomécanique est meilleure dans les deux parties. Les différents résultats obtenus sont décrits dans ce manuscrit. / The contamination of surfaces by bacteria and the emergence of antimicrobial resistant strains are very worrying problems in different areas such as hospital and food. This contamination begins with the adhesion of pathogenic bacteria on a surface until the formation of biofilms. These biofilms contribute to the emergence of resistances of certain bacterial strains to conventional treatments. To answer these problems of surface contamination, this thesis work focuses on the development of new antibacterial materials based on pulp fibers. In the first part, we focused on the development of an antibacterial paper by grafting, via triazine link, two essential oil compounds, thymol and carvacrol, known for their antibacterial activities. The microbiological evaluation of the developed materials against the two bacterial strains tested, E. coli and S. aureus, showed a bacteriostatic effect. These materials block the bacterial growth thus preventing the biofilms formation. Synergy between thymol and carvacrol grafted onto paper has also been shown. In a second part, our study focused on the development of an antibacterial paper that acquires its activity only after the grafting and formation of "aryl-1,2,3-triazole", the active motif. The grafting is carried out by a reaction of "Click Chemistry", the copper (I)-catalyzed Azide Alkyne Cycloaddition. The antibacterial tests reveal the importance of the aryl substituent, the influence of the contact time and the relevance of using mixtures of materials. The antibacterial activity observed on the thermomechanical pulp fibers is better in both parts. The different results obtained are described in this manuscript.

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