Master of Science / Department of Civil Engineering / Dunja Peric / The purpose of this research was to investigate the effects of drying on the strength gain of masonry sand stabilized with a co-product from wood pulping called calcium lignosulfonate. Lignin is an amorphous polymer found in plant cell walls. It provides protection against disease and allows the transport of water and nutrients. Adhesive properties of lignin generated interest in adding its modifications to soils as means to prevent erosion from wind and vehicle traffic on unpaved roads. Lignin has the potential to become a more sustainable alternative to traditional stabilizers because its source is renewable and abundant, and its toxicity is negligible. Extensive testing has recently been completed to quantify the stress-strain relationships and Mohr-Coulomb strength parameters of sand- calcium lignosulfonate-water (S-CaL-W) mixes at early age (Bartley, 2011). The experimental program consisted of performing Standard Proctor Tests to determine maximum densities and optimum moisture contents for mixes having different gravimetric lignin contents and direct shear tests on selected sample configurations. Based on these results, it was decided to conduct shear strength testing of the samples containing 4%, 6% and 9% of calcium lignosulfonate after they had been exposed to air drying. To this end, responses of the selected sample configurations to drying at 71° F and 27% relative humidity were measured to determine the target water contents for shear strength testing. Drying curves were obtained by plotting the measured water content or water to CaL ratio versus the elapsed time. Drying times for shear strength were chosen based on how long it took the moisture contents to decrease by specified levels. The available results of direct shear tests show that drying significantly increases both the cohesion and the friction angle of the S-CaL-W mixes with respect to the early age cohesion and friction angle. In addition to the direct shear test program a laboratory compaction test was conducted on CaL and water only, thus providing the maximum dry density of CaL and the corresponding optimum water to CaL ratio. It is also noted that relative humidity was discovered to be the limiting factor in the strength gain of S-CaL-W mixes. The reasons behind its sensitivity to water are due to the presence of HPLC sugars within the calcium lignosulfonate structure. These sugars hold the water through the chemical interaction of the sugars with hydrogen ions and water molecules.

Due to the petroleum crisis and its consequent emission problems, fuel cells gain an important place in the application of alternative energy. They are a kind of electrochemical device that converts chemical energy directly into electrical energy. The Direct Methanol Fuel Cells (DMFC) use polymer membranes as the electrolyte; the polymer membranes are capable of conducting hydrogen protons. The fuel cell system is still expensive and the proton exchange membrane has contributed significantly the high cost. At present, perfluorosulfonic acid membranes (PFSA) (e.g. Nafion®, by DuPont) have been widely investigated. However they showed high methanol crossover and high swelling that lead low cell efficiency. The main goal of the thesis is to prepare novel proton exchange membranes to apply in the DMFC. PEG and PA membranes compuestas fueron preparadas. Derivados del ácido fosfórico y lignosulfonados (LS) fueron incluidos en la estructura de la PA para actuar como agentes transportadores de protones. El mecanismo de la conductividad de protón es "hopping". Ellos mostraron el más baja del transporte de metanol.Se obtuvieron también membranas híbridas de LS, preparadas mediante la mezcla de los dos polímeros, LS y PSU, siguiendo el método de precipitación en inmersión. Las propiedades electroquímicas de las membranas de LS fueron caracterizadas. Las membranas de LS alcanzaron conductividades de protón aceptables (10-20 mS/cm) con capacidad de intercambio iónico muy baja (IEC) (60 veces más baja que Nafion). "Membrane electrode assemblies" (MEAs) fueron preparadas y sus rendimientos de celda fueron medidos en una celda individual directa de metanol (DMFC). LS membrana is the highlight point of this thesis. It demonstrated the first that LS is a good proton exchange material although it is a waste from the paper industry. It also proved that porous membrane can be used in the DMFC with acceptable proton conductivity and low methanol permeability, which is a totally new way from the existing literatures.The results have been published on international journals and have been presented on international conferences:1. X. Zhang, A. Glüsen, R. Garcia-Valls, Porous Lignosulfonate membrane for direct methanol fuel cells, accepted by Journal of Membrane Science, 20052. X. Zhang, J. Benavente, R. Garcia Valls, Lignin-based Membranes for Electrolyte Transference, Journal of Power Sources, 145 (2005) 2923. X. Zhang, L. Pitol Filho, C. Torras, R. Garcia Valls, Experimental and Computational Study of Proton and Methanol Permeability through Composite Membranes, Journal of Power Sources, 145 (2005) 2234. J. Benavente, X. Zhang, R. Garcia Valls, Modification of Polysulfone Membranes with Polyethylene Glycol and Lignosulfate: Electrical Characterization by Impedance Spectroscopy Measurements, Journal of Colloid and Interface Science, 285 (2005) 273-2805. X. Zhang, R. Garcia-Valls, Proton transport membrane containing lignin compound for direct methanol fuel cells (Poster), 5th Ibero American Congress on Membrane Science and Technology, 2005, Valencia- Spain 6. X. Zhang, J. Benavente and R. Garcia-Valls, Lignin-based membranes for electrolyte transference (Oral presentation), Fuel Cell Science & Technology, Oct. 2004, Munich- Germany. 7. X. Zhang, R. Garcia-Valls, New membranes for Proton Transport in DMFC (Poster), Euromembrane Sep. 2004, ISBN: 3-930400-65-0, p. 64, Hamburg- Germany, 8. X. Zhang, R. Garcia-Valls, Lignosulfonate Application in Proton Transport Membrane (Oral presentation), 2nd World Conference and Technology Exhibition on Biomass for Energy, Industry and Climate Protection, May. 2004, Rome- Italy9. X. Zhang, R. Garcia-Valls, Proton Selective Composite Membrane for Direct Methanol Fuel Cell (Oral presentation), 5th NYM (Network Young Membrains) Oct. 2003, ISBN: 84-688-3132-8, p. 199, Barcelona, Spain10. X. Zhang, R. Garcia-Valls, A. Jiménez-López, E. Rodríguez-Castellón and J. Benavente, Electrical and Chemical Surface Characterization of Lignosulfate/Polysulfone Membranes for Fuel Cells Application, International Conference on "New Proton Conducting Membranes and Electrodes for PEM FCs", Oct. 2005, Assisi, Italy. / Debido a la crisis de petróleo y a los problemas de emisión, las pilas de combustible adquieren un lugar importante en la aplicación de la energía alternativa. Son una clase de dispositivo electroquímico que convierte la energía química directamente en energía eléctrica. Las celdas de combustible de metanol (DMFC) usan membranas de polímero como el electrolito; las membranas de polímero son capaces de transportar protones de hidrógeno. El sistema de la celda de combustible todavía es costoso y las membranas de intercambio de protón han contribuido significativamente para el costo elevado.Actualmente, las membranas de ácido perfluorosulfonico (PFSA) (por ejemplo, Nafion ®, de DuPont) ten sido investigadas extensamente. Sin embargo mostraron alto paso de metanol e alto "swelling" lo que lleva a una eficiencia de celda baja.El objetivo principal de la tesis es preparar membranas de intercambio de protón nuevas para la aplicación en DMFC. Membranas compuestas de PEG y de PA fueron preparadas. Derivados del ácido fosfórico y lignosulfonados (LS) fueron incluidos en la estructura de la PA para actuar como agentes transportadores de protones. El mecanismo de conductividad de protón es "hopping". Ellos mostraron el transporte de metanol más bajo.Se obtuvieron también membranas híbridas de LS, preparadas mediante la mezcla de los dos polímeros, LS y PSU, siguiendo el método de precipitación en inmersión. Las propiedades electroquímicas de las membranas de LS fueron determinadas. Las membranas de LS alcanzaron conductividades de protón aceptables (10-20 mS/cm) con capacidad de intercambio iónico muy baja (IEC) (60 veces más baja que Nafion). "Membrane electrode assemblies" (MEAs) fueron preparadas y sus rendimientos de celda fueron medidos en una celda individual directa de metanol (DMFC).Las membranas de LS son el punto principal de esta tesis. Primero se demostró que LS es un material de intercambio de protón muy bueno aunque sea un residuo de la industria de papel. También se probó que membranas porosas pueden ser usadas en DMFC con una conductancia de protón aceptable y baja permeabilidad de metanol, lo que es una manera totalmente nueva comparada a la literatura existente.Los resultados han sido divulgados en revistas internacionales y han sido presentados en conferencias internacionales:1. X. Zhang, A. Glüsen, R. Garcia-Valls, Porous Lignosulfonate membrane for direct methanol fuel cells, accepted by Journal of Membrane Science, 20052. X. Zhang, J. Benavente, R. Garcia Valls, Lignin-based Membranes for Electrolyte Transference, Journal of Power Sources, 145 (2005) 2923. X. Zhang, L. Pitol Filho, C. Torras, R. Garcia Valls, Experimental and Computational Study of Proton and Methanol Permeability through Composite Membranes, Journal of Power Sources, 145 (2005) 2234. J. Benavente, X. Zhang, R. Garcia Valls, Modification of Polysulfone Membranes with Polyethylene Glycol and Lignosulfate: Electrical Characterization by Impedance Spectroscopy Measurements, Journal of Colloid and Interface Science, 285 (2005) 273-2805. X. Zhang, R. Garcia-Valls, Proton transport membrane containing lignin compound for direct methanol fuel cells (Poster), 5th Ibero American Congress on Membrane Science and Technology, 2005, Valencia- Spain6. X. Zhang, J. Benavente and R. Garcia-Valls, Lignin-based membranes for electrolyte transference (Oral presentation), Fuel Cell Science & Technology, Oct. 2004, Munich- Germany.7. X. Zhang, R. Garcia-Valls, New membranes for Proton Transport in DMFC (Poster), Euromembrane Sep. 2004, ISBN: 3-930400-65-0, p. 64, Hamburg- Germany,8. X. Zhang, R. Garcia-Valls, Lignosulfonate Application in Proton Transport Membrane (Oral presentation), 2nd World Conference and Technology Exhibition on Biomass for Energy, Industry and Climate Protection, May. 2004, Rome- Italy9. X. Zhang, R. Garcia-Valls, Proton Selective Composite Membrane for Direct Methanol Fuel Cell (Oral presentation), 5th NYM (Network Young Membrains) Oct. 2003, ISBN: 84-688-3132-8, p. 199, Barcelona, Spain10. X. Zhang, R. Garcia-Valls, A. Jiménez-López, E. Rodríguez-Castellón and J. Benavente, Electrical and Chemical Surface Characterization of Lignosulfate/Polysulfone Membranes for Fuel Cells Application, International Conference on "New Proton Conducting Membranes and Electrodes for PEM FCs", Oct. 2005, Assisi, Italy La tesis tuvo la cooperación del Forschungszentrum Jülich, Alemania y la doctoranda esta solicitando el titulo de Doctorado Europeo.

Considerando o grande interesse atual em biocompósitos, seja pela utilização de fibras lignocelulósicas como reforço em compósitos poliméricos ou pela produção de matrizes oriundas de fontes renováveis, buscou-se neste estudo a melhora de propriedades do termorrígido fenólico com a inserção de fibras de sisal tratadas com lignosulfonato de sódio. As fibras de sisal, largamente produzidas no Brasil, são provenientes de fontes renováveis, possuem baixa densidade e apresentam boas propriedades mecânicas. Lignosulfonatos são obtidos através do processo de polpação sulfito da madeira, sendo considerado material renovável. As fibras de sisal foram modificadas via adsorção de lignosulfonato via aquecimento a 70 °C/1h e por meio de irradiação com ultra-som em diferentes tempos (1h e 2h) e por 14h de imersão na solução aquosa de lignosulfonato seguindo de 1 h de irradiação com ultra-som. O lignosulfonato também foi utilizado como substituinte do fenol no preparo de resinas fenol-formaldeído, o que é possível devido à presença de anéis fenólicos em sua estrutura. As fibras de sisal, antes e após os tratamentos, foram caracterizadas segundo teor de componentes majoritários, análise elementar, microscopia eletrônica de varredura (MEV), espectroscopia na região do infravermelho (IV), ensaio de tração, análise térmica (TG e DSC) e difração de raios X. Estes resultados revelaram o efeito do ultra-som sobre a superfície da fibra, a presença de lignosulfonato na superfície das fibras e aumento relativo da resistência à tração após as modificações. Os pré-polímeros fenólico e lignosulfonato-formaldeído foram caracterizados por cromatografia de exclusão de tamanho, IV, TG e DSC. Os compósitos preparados em todo trabalho foram caracterizados por ensaio de resistência ao impacto Izod sem entalhe, ensaio de resistência à flexão, análise térmica dinâmico-mecânica, TG, DSC, ensaio de absorção de água e condutividade térmica. O ensaio de resistência ao impacto para os compósitos fenólicos indicaram uma melhora nesta propriedade quando fibras modificadas (à 70 °C/1 h e ultra-som/1 h) foram utilizadas para preparar estes materiais. O ensaio de flexão também indicou melhora de propriedade quando as fibras modificadas por irradiação com ultra-som (1 e 2 h) foram utilizadas em compósitos fenólicos. Os resultados obtidos mostraram que os tratamentos com lignosulfonato de sódio associados a irradiação ultra-som é um tratamento promissor, pois modifica a morfologia da superfície das fibras sem levar à degradação química, sendo que a separação dos feixes de fibra que ocorre permite melhor interação fibra/matriz na interface. O ensaio de absorção de água, mostrou que os tratamentos aplicados à superfícies influenciam pouco na absorção de água dos compósitos fenólicos. Todos os compósitos preparados com matriz lignosulfonato-formaldeído obtiveram valores resistência ao impacto superiores que os compósitos fenólicos, sendo que o compósito preparado com fibra não-modificada alcançou 1000 J.m-1. As modificações nas fibras de sisal, para estes compósitos, não provocaram os efeitos esperados nas propriedades mecânicas destes materiais, embora se tenha observado uma boa adesão na interface fibra/matriz pelas imagens de MEV, resultado da semelhança químico-estrutural entre a matriz e a fibra de sisal. Uma melhora nas propriedades mecânicas dos materiais aqui investigados faz com que estes se tornem atraentes para aplicações nas indústrias automobilística e aeronáutica, visto que na sua produção são utilizados materiais oriundos de fontes renováveis, como as fibras lignocelulósicas e o lignosulfonato, e tratamentos físicos, como o aquecimento e a irradiação de ultra-som, estando de acordo com políticas de sustentabilidade e preservação do meio-ambiente. / Due to the great current interest in biocomposites because of both the use of lignocellulosic fibers as reinforcers of polymer matrices and the production of matrices prepared from renewable raw material, this study has sought to improve the properties of phenolic thermosets using sodium lignosulphonate as a macromonomer, and the insertion of sisal fibers, either treated or not with sodium lignosulphonate, as a reinforcer. Sisal fibers, which are widely produced in Brazil, are renewable, have low density, and present good mechanical properties. Lignosulphonates are obtained by a wood sulphite pulping process, thus using materials from a renewable source. The sisal fibers were modified by lignosulphonate adsorption by heating at 70 °C for 1 h, followed by sonication for different time periods (1 h and 2 h) or by immersion for 14 h in aqueous lignosulphonate solution, followed by sonication for 1 h. Fiber surface treatment by adsorption of a compatibilizing agent rather than by chemical reaction was chosen with the intent of minimizing the reduction of the fiber mechanical properties. The major sisal fiber components were characterized before and after treatment by elemental analysis, scanning electron microscopy, infrared spectroscopy (IR), tensile strength, thermogravimetry (TG) and differential scanning calorimentry (DSC), and X-ray diffraction. The treatments resulted in a significant increase in fiber tensile strength. The phenolic pre-polymers and lignosulphonate-formaldehyde were characterized by size exclusion chromatography, IR, TG, and DSC. The composites were characterized as to Izod impact strength, flexural strength, dynamic mechanic thermal analysis, TG and DSC, water absorption, and thermal conductivity. The phenolic composites reinforced with modified fibers (70 °C/1 h and sonication/1 h) presented improved impact strength. The flexural strength of phenolic composites reinforced with sonication modified fibers (1 and 2 h) improved. The results obtained demonstrate that fiber treatment with sodium lignosulphonate associated with sonication is a promising method, as it modifies the surface morphology of the fibers without drastically changing their properties. The resulting fiber bundle separation allows for a better fiber/matrix interaction. The water absorption assay demonstrated that the fiber surface treatment had little influence on the water absorption of phenolic composites reinforced with these fibers. All the composites prepared with the lignosulphonate-formaldehyde matrix had higher impact strength than phenolic composites; the composite prepared with non-modified fiber reached 1000 J.m-1. The modification of sisal fibers in these composites did not induce effects on the material mechanical properties. However, good adhesion was observed at the fiber/matrix interface, as shown by the SEM images, due to the chemical-structural similarity of the matrix and treated sisal fiber. In this case, the modification of the matrix formulations was the factor that most influenced the material properties. Both the thermosets and the composites had similar thermal conductivity, that is, the presence of untretated or treated sisal fibers did not alter the thermal conductivity of the material. The materials properties that were investigated here show that they may have potential application in the car and aircraft industries (non-structural applications) with the advantage that their production uses renewable resource materials, such as lignocellulosic fibers and lignosulphonate, and physical treatments, such as heating and sonication, meeting the current sustainability and environment preservation policies.

<p>The major issue concerns how the different lignosulfonate types changes the rheological properties of the cement based material (concrete, mortar and cement paste) as a function of temperature and time. In such terms, it is demonstrated that the high molecular weight lignosulfonates performs far better than the low molecular weight ones. The former type also performs considerable better compared to a naphthalene based polymer. </p><p>The above investigation is done with help from the second part of this thesis, which identifies some of the parameters p1, p2,... affecting the shear viscosity η = η ( p1, p2,...) of the cement based material. This is done by investigating the thixotropic behavior of cement paste mixed with either lignosulfonates or naphthalene. The thixotropic behavior is directly related to coagulation, dispersion and re-coagulation of the cement particles. In making the analysis, a modification is applied to the Hattori-Izumi theory, which is a theory about the bookkeeping of the number of reversible coagulated connections between the cement particles. The modification consist, among other things, of include a fading memory to the analysis. That is, the cement paste is allowed to remember its recent past. By a combination of experimental results and numerical simulations, it is demonstrated that such memory term is very important.</p><p>An experimental error is present during a viscometric measurement on concrete (a coaxial cylinders viscometer is used). The error is generated by particle migration. Investigating and compensating for this error constitutes the third part of this thesis. Realizing the nature of this error, some corrections are applied. However, with these corrections, one is only extracting the viscometric values of a "fat'' concrete that surrounds the inner cylinder of the viscometer after the particle migration is basically complete, and not of the concrete in the original homogenous state.</p>

The major issue concerns how the different lignosulfonate types changes the rheological properties of the cement based material (concrete, mortar and cement paste) as a function of temperature and time. In such terms, it is demonstrated that the high molecular weight lignosulfonates performs far better than the low molecular weight ones. The former type also performs considerable better compared to a naphthalene based polymer. The above investigation is done with help from the second part of this thesis, which identifies some of the parameters p1, p2,... affecting the shear viscosity η = η ( p1, p2,...) of the cement based material. This is done by investigating the thixotropic behavior of cement paste mixed with either lignosulfonates or naphthalene. The thixotropic behavior is directly related to coagulation, dispersion and re-coagulation of the cement particles. In making the analysis, a modification is applied to the Hattori-Izumi theory, which is a theory about the bookkeeping of the number of reversible coagulated connections between the cement particles. The modification consist, among other things, of include a fading memory to the analysis. That is, the cement paste is allowed to remember its recent past. By a combination of experimental results and numerical simulations, it is demonstrated that such memory term is very important. An experimental error is present during a viscometric measurement on concrete (a coaxial cylinders viscometer is used). The error is generated by particle migration. Investigating and compensating for this error constitutes the third part of this thesis. Realizing the nature of this error, some corrections are applied. However, with these corrections, one is only extracting the viscometric values of a "fat'' concrete that surrounds the inner cylinder of the viscometer after the particle migration is basically complete, and not of the concrete in the original homogenous state.

Considerando o grande interesse atual em biocompósitos, seja pela utilização de fibras lignocelulósicas como reforço em compósitos poliméricos ou pela produção de matrizes oriundas de fontes renováveis, buscou-se neste estudo a melhora de propriedades do termorrígido fenólico com a inserção de fibras de sisal tratadas com lignosulfonato de sódio. As fibras de sisal, largamente produzidas no Brasil, são provenientes de fontes renováveis, possuem baixa densidade e apresentam boas propriedades mecânicas. Lignosulfonatos são obtidos através do processo de polpação sulfito da madeira, sendo considerado material renovável. As fibras de sisal foram modificadas via adsorção de lignosulfonato via aquecimento a 70 &deg;C/1h e por meio de irradiação com ultra-som em diferentes tempos (1h e 2h) e por 14h de imersão na solução aquosa de lignosulfonato seguindo de 1 h de irradiação com ultra-som. O lignosulfonato também foi utilizado como substituinte do fenol no preparo de resinas fenol-formaldeído, o que é possível devido à presença de anéis fenólicos em sua estrutura. As fibras de sisal, antes e após os tratamentos, foram caracterizadas segundo teor de componentes majoritários, análise elementar, microscopia eletrônica de varredura (MEV), espectroscopia na região do infravermelho (IV), ensaio de tração, análise térmica (TG e DSC) e difração de raios X. Estes resultados revelaram o efeito do ultra-som sobre a superfície da fibra, a presença de lignosulfonato na superfície das fibras e aumento relativo da resistência à tração após as modificações. Os pré-polímeros fenólico e lignosulfonato-formaldeído foram caracterizados por cromatografia de exclusão de tamanho, IV, TG e DSC. Os compósitos preparados em todo trabalho foram caracterizados por ensaio de resistência ao impacto Izod sem entalhe, ensaio de resistência à flexão, análise térmica dinâmico-mecânica, TG, DSC, ensaio de absorção de água e condutividade térmica. O ensaio de resistência ao impacto para os compósitos fenólicos indicaram uma melhora nesta propriedade quando fibras modificadas (à 70 &deg;C/1 h e ultra-som/1 h) foram utilizadas para preparar estes materiais. O ensaio de flexão também indicou melhora de propriedade quando as fibras modificadas por irradiação com ultra-som (1 e 2 h) foram utilizadas em compósitos fenólicos. Os resultados obtidos mostraram que os tratamentos com lignosulfonato de sódio associados a irradiação ultra-som é um tratamento promissor, pois modifica a morfologia da superfície das fibras sem levar à degradação química, sendo que a separação dos feixes de fibra que ocorre permite melhor interação fibra/matriz na interface. O ensaio de absorção de água, mostrou que os tratamentos aplicados à superfícies influenciam pouco na absorção de água dos compósitos fenólicos. Todos os compósitos preparados com matriz lignosulfonato-formaldeído obtiveram valores resistência ao impacto superiores que os compósitos fenólicos, sendo que o compósito preparado com fibra não-modificada alcançou 1000 J.m-1. As modificações nas fibras de sisal, para estes compósitos, não provocaram os efeitos esperados nas propriedades mecânicas destes materiais, embora se tenha observado uma boa adesão na interface fibra/matriz pelas imagens de MEV, resultado da semelhança químico-estrutural entre a matriz e a fibra de sisal. Uma melhora nas propriedades mecânicas dos materiais aqui investigados faz com que estes se tornem atraentes para aplicações nas indústrias automobilística e aeronáutica, visto que na sua produção são utilizados materiais oriundos de fontes renováveis, como as fibras lignocelulósicas e o lignosulfonato, e tratamentos físicos, como o aquecimento e a irradiação de ultra-som, estando de acordo com políticas de sustentabilidade e preservação do meio-ambiente. / Due to the great current interest in biocomposites because of both the use of lignocellulosic fibers as reinforcers of polymer matrices and the production of matrices prepared from renewable raw material, this study has sought to improve the properties of phenolic thermosets using sodium lignosulphonate as a macromonomer, and the insertion of sisal fibers, either treated or not with sodium lignosulphonate, as a reinforcer. Sisal fibers, which are widely produced in Brazil, are renewable, have low density, and present good mechanical properties. Lignosulphonates are obtained by a wood sulphite pulping process, thus using materials from a renewable source. The sisal fibers were modified by lignosulphonate adsorption by heating at 70 &deg;C for 1 h, followed by sonication for different time periods (1 h and 2 h) or by immersion for 14 h in aqueous lignosulphonate solution, followed by sonication for 1 h. Fiber surface treatment by adsorption of a compatibilizing agent rather than by chemical reaction was chosen with the intent of minimizing the reduction of the fiber mechanical properties. The major sisal fiber components were characterized before and after treatment by elemental analysis, scanning electron microscopy, infrared spectroscopy (IR), tensile strength, thermogravimetry (TG) and differential scanning calorimentry (DSC), and X-ray diffraction. The treatments resulted in a significant increase in fiber tensile strength. The phenolic pre-polymers and lignosulphonate-formaldehyde were characterized by size exclusion chromatography, IR, TG, and DSC. The composites were characterized as to Izod impact strength, flexural strength, dynamic mechanic thermal analysis, TG and DSC, water absorption, and thermal conductivity. The phenolic composites reinforced with modified fibers (70 &deg;C/1 h and sonication/1 h) presented improved impact strength. The flexural strength of phenolic composites reinforced with sonication modified fibers (1 and 2 h) improved. The results obtained demonstrate that fiber treatment with sodium lignosulphonate associated with sonication is a promising method, as it modifies the surface morphology of the fibers without drastically changing their properties. The resulting fiber bundle separation allows for a better fiber/matrix interaction. The water absorption assay demonstrated that the fiber surface treatment had little influence on the water absorption of phenolic composites reinforced with these fibers. All the composites prepared with the lignosulphonate-formaldehyde matrix had higher impact strength than phenolic composites; the composite prepared with non-modified fiber reached 1000 J.m-1. The modification of sisal fibers in these composites did not induce effects on the material mechanical properties. However, good adhesion was observed at the fiber/matrix interface, as shown by the SEM images, due to the chemical-structural similarity of the matrix and treated sisal fiber. In this case, the modification of the matrix formulations was the factor that most influenced the material properties. Both the thermosets and the composites had similar thermal conductivity, that is, the presence of untretated or treated sisal fibers did not alter the thermal conductivity of the material. The materials properties that were investigated here show that they may have potential application in the car and aircraft industries (non-structural applications) with the advantage that their production uses renewable resource materials, such as lignocellulosic fibers and lignosulphonate, and physical treatments, such as heating and sonication, meeting the current sustainability and environment preservation policies.

The demand for bio-plastics is constantly growing, due to the increasing use of synthetic plastic, their non environmentally friendly properties and long degradation time. This thesis explored the possibility to use starch-lignosulfonate mixtures for food packaging. Films are prepared from potato starch and two different types of lignosulfonates, calcium and sodium respectively using mold casting. The films are compared to pure potato starch films in respect to their mechanical properties and moisture absorption. Characterization of the films is also conducted using scanning electron microscopy, energy-dispersive X- ray spectroscopy and light microscopy to see the interaction between the potato starch and lignosulfonates. The tensile test reveals that neither of the lignosulfonates do have a plasticizing effect on the potato starch films. The energy-dispersive X-ray spectroscopy conceded that the lignosulfonates are homogeneously dispersed throughout the film both on the surface and cross section. The moisture absorption test showed that the uptake of water does not decrease by adding lignosulfonates to the potato starch film. From these results it can be concluded that it is possible to produce films from potato starch and lignosulfonates in various ratios. But the potato starch:lignosulfonate films are not a viable option for food packaging due to their brittleness and high moisture uptake. / Efterfrågan på bioplast växer ständigt på grund av den ökande användingen av syntetiska plaster, deras icke miljövänliga egenskaper och den långa nedbrytningstiden. Denna avhandling undersöker möjligheten att använda blandningar av stärkelse-lignosulfonat i livsmedelsförpackningar. Potatisstärkelse och två olika typer av lignosulfonater med kalcium och natrium användes för att tillverka filmer genom formgjutning. Filmerna jämförs med filmer med ren potatisstärkelse, med avseende på deras mekaniska egenskaper och fuktabsorption. Karakterisering av filmerna genomförs även med hjälp av svepelektronmikroskop, energiröntgenspektroskopi och ljusmikroskopi för att se interaktionen mellan potatisstärkelse och lignosulfonater. Dragproverna visar att ingen av lignosulfonaterna har mjukgörande effekt på potatisstärkelsefilmerna. Energiröntgenspektroskopin visade att lignosulfonaterna är homogent dispergerade i hela filmen både på ytan och i tvärsnittet. Fuktabsorptionstestet visade att upptaget av vatten inte minskar genom tillsats av lignosulfonater i potatisstärkelse-filmen. Från dessa resultat kan man dra slutsatsen att det är möjligt att framställa filmer från potatisstärkelse och lignosulfonater i olika förhållanden. Men potatisstärkelse: lignosulfonatfilmer är inte ett hållbart alternativ för livsmedelsförpackningar på grund av sin sprödhet och höga fuktupptagning.

As resinas do tipo fenólica são amplamente utilizadas devido à sua diversidade de aplicações. Considerando as inúmeras vantagens desta resina (estabilidade térmica e dimensional, alta resistência à chama, etc.), este trabalho teve como um dos objetivos melhorar as propriedades mecânicas do termorrígido fenólico, pois estes são frágeis quando não reforçados. Fibras lignocelulósicas naturais foram usadas como reforço no termorrígido fenólico, o que levou a obtenção de biocompósitos. Devido a grande disponibilidade de fibras de bagaço de cana de açúcar no país, como subproduto de agroindústrias, estas fibras foram utilizadas na produção dos compósitos (sendo substituído em até 70% da matriz termorrígida por fibra natural), com a finalidade de atribuir maior valor agregado que o tradicionalmente encontrado para estas fibras. Tendo em vista que atualmente estas fibras podem ser obtidas como resíduo da agroindústria na forma queimada e não queimada, um estudo comparativo foi feito usando ambas as fibras. Compósitos fenólicos foram preparados com as fibras queimadas e não queimadas e os resultados obtidos de resistência ao impacto, módulo de armazenamento e absorção de água mostraram que não há diferenças significativas entre as propriedades de ambos. Considerando estes resultados, a continuidade do trabalho foi realizada com as fibras de bagaço de cana queimado, devido à maior disponibilidade atual destas fibras. Também foram utilizadas fibras de sisal, tradicionalmente conhecidas pelas excelentes propriedades mecânicas e disponibilidade em grande escala no país, para fins comparativos. Adicionalmente, visando aumentar a proporção de uso de matéria prima oriunda de fonte renovável, o lignossulfonato de sódio (NaLS) e lignina organossolve (LO), macromoléculas obtidas a partir de fibras lignocelulósicas, substituíram em 100% o fenol nas reações de obtenção de resinas do tipo resol (obtidas em meio alcalino). Ainda, o formaldeído foi substituído pelo glutaraldeído, um dialdeído, visando-se síntese de resinas alternativas a fenol-formaldeído, tradicionalmente usada. Também, as fibras de bagaço de cana queimadas foram tratadas em solução de NaLS, em banho de ultrassom. Este tratamento foi escolhido por se tratar do uso de macromolécula oriunda de fontes renováveis, assim como pelo fato de a fibra (bagaço de cana) conter alto teor de lignina, o que leva à perspectiva de intensificação da afinidade fibra/agente de tratamento, além de intensificar as interações fibra/matriz, devido à presença de anéis do tipo fenólico em ambas, superfícies das fibras e matriz. As fibras foram caracterizadas quanto à composição química e analisadas via termogravimetria (TG), calorimetria exploratória diferencial (DSC), microscopia eletrônica de varredura (MEV), cromatografia gasosa inversa (IGC), espectroscopia na região de infravermelho (IV), cromatografia liquida de alta performance (HPLC, para determinação do teor de açúcares no bagaço de cana queimado) e difração de raios X. O termorrígido fenólico (não reforçado) e compósitos (matriz fenólica e matrizes baseadas em LO e NaLS reforçados por fibras com distribuição aleatória, em diferentes proporções e comprimentos) foram caracterizados por TG, DSC, IV, MEV, DMTA, resistência ao impacto Izod, resistência à flexão quanto à capacidade de absorção de água. Termorrígidos preparados a base de NaLS apresentaram grande fragilidade após a moldagem, tendo sido apenas submetidos a análises de TG, DSC e cromatografia gasosa inversa (IGC), devido à impossibilidade de realizar outros ensaios. As análises de IGC foram realizadas para fibras e matriz, obtendo-se parâmetros relacionados à energia de superfície e disponibilidade de sítios ácidos e básicos. Os resultados de IGC obtidos para as fibras, tratadas e não tratadas, confirmaram que houve a adsorção do lignossulfonato sódio à superfície destas devido ao aumento de sítios ativos (ácidos e básicos) disponíveis. Os valores de IGC obtidos para as matrizes sugerem que as interações fibra/matriz são favorecidas, principalmente quando o NaLS está presente em ambos os componentes (fibra/matriz). Os resultados obtidos na caracterização dos compósitos indicaram que o lignossulfonato de sódio e a lignina organossolve podem substituir o fenol na formulação de resinas. A utilização de fibras como reforço melhorou as propriedades mecânicas dos materiais, comparativamente aos termorrígidos. Dentre os compósitos preparados com bagaço de cana, a amostra que apresentou melhor desempenho nos ensaios de impacto foram os compósitos de matrizes baseadas em glutaraldeído-LO (112 J m-1) e glutaraldeído-NaLS (82 J m-1). Os compósitos de matriz baseada em formaldeído-NaLS reforçados com fibras de sisal apresentaram melhor desempenho no ensaio de resistência ao impacto (1029 J m-1) e menor quantidade de água absorvida quando imerso em água, comparado aos demais compósitos preparados neste trabalho. As análises de MEV comprovaram a intensificação da adesão entre as fibras de sisal e a matriz, quando esta é preparada a partir de NaLS. Compósitos reforçados com fibras de sisal foram os que apresentaram melhor desempenho mecânico, tanto em resistência ao impacto quanto em flexão, provavelmente devido às propriedades intrínsecas das fibras de sisal. No geral, quando os termorrígidos foram reforçados com as fibras lignocelulósicas, bagaço de cana ou sisal, apresentaram resultados de estabilidade térmica e mecânica satisfatórios. Destaca-se que compósitos preparados com alto teor de material proveniente de fonte renovável, como os compósitos reforçados com até 70% de fibra, e os compósitos com matriz baseada em 100% de lignossulfonato de sódio e lignina organossolve, apresentaram grande potencial para diferentes aplicações, tais como no setor de embalagens e automotivo, neste caso para aplicações não estruturais. / Phenolic resins are widely known due to their diverse applications. Considering the many advantages of this type of resin (flame resistance, thermal and dimensional stability, etc), this study has one objective: the improvement of the mechanical properties of the phenolic thermoset, because this material is fragile when it is not reinforced. Natural lignocellulosic fibers were used as reinforcement in the phenolic thermoset leading to the obtaining of biocomposites. Because the fibers from sugarcane bagasse are byproducts widely available by agricultural industries in this country, these fibers were used in the production of the composites (the thermoset phenolic was replaced by up to 70% natural fibers) - the purpose was to assign greater value than traditionally found for these fibers. Currently, sugarcane fibers can be obtained from natural and burned bagasse. A comparative study was realized using both fibers. Phenolic composites were prepared with the burned fibers and the results obtained from the impact resistance, storage modulus and water absorption showed that they are not significantly different when it comes to the properties of both. Considering these results, the continuity of this study was realized with the burned fibers of sugarcane due to the higher and current availability of this fiber. Lignocellulosic fibers, are traditionally known because of their excellent mechanical properties and wide availability, like the sisal ones used in the present work for comparative reasons. Sisal fibers are available in large scale, facilitating their use. Additionally, sodium lignosulphonate (NaLS) and organosolv lignin (LO), which are macromolecules obtained from the lignocellulosics fibers were used to increase the proportion of the raw materials from renewable sources for a possible phenol substitute in resin reaction, resol type (an alkaline medium). Also, formaldehyde was replaced by glutaraldehyde aiming at the synthesis alternative resin to phenol-formaldehyde, which is traditionally used. Furthermore, burned sugar cane bagasse fibers were treated in NaLS solution, in ultrasonic bath. This treatment was chosen because this macromolecule is from renewable resources and as well as the fibers (sugarcane bagasse) have high content of lignin, which leads to the perspective of affinity intensification between fibers/lignin and fibers/matrix, due to the presence of the aromatics rings in both surfaces. The fibers were characterized in terms of chemical composition and analyzed by thermogravimetry (TG), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), inverse gas chromatography (IGC), infrared spectroscopy (IV), high performance liquid chromatography (HPLC, determination of the sugar content in the burned sugar cane bagasse) and X-ray diffraction. The lignin and resin were characterized by SEC, RMN 1H and RMN 31P. The thermosets (not reinforced) and composites (phenolic matrix and LO and NaLS matrix reinforced with randomly dispersed fibers) were characterized by TG, DSC, IV, Izod impact strength, MEV, flexural strength, DMTA and also the water absorption capacity was evaluated. Thermoset prepared based on NaLS showed great weakness after molding, being submitted only to analysis by TG, DSC and inverse gas chromatography (IGC), due to the impossibility of doing other tests. IGC analysis were realized for fibers and matrix. Parameters related to surface energy and availability of acids and basics sites were obtained. IGC results obtained for the fibers, treated and untreated, confirm that there was adsorption of lignosulphonate in these surfaces due to the increase of available active sites (acids and basics). IGC values obtained for matrix suggest that fiber/matrix interactions are favored, mainly when the NaLS is present in both components (fiber/matrix). The results obtained in the characterization of the composites indicated that lignosulphonate sodium and organosolv lignin can substitute the phenol in the resin formulation. Fibers used as reinforcement improved the mechanical properties of materials, compared to thermosets. Among the composites prepared with sugarcane bagasse, the sample that showed better performance in the impact test were the composites based on glutaraldehyde -LO (112 J m-1) and glutaraldehyde -NaLS (82 J m-1). Composites based on formaldehyde -NaLS reinforced with sisal fibers showed better performance in impact test (1009 J m-1) and less water absorbed when immersed in water, compared to others composites prepared in this study. SEM analysis confirmed the adhesion intensification between the sisal fibers and the matrix, when this is prepared from NaLS. Composites reinforced with sisal fibers showed the best mechanical performance, such as impact strength and flexural strength, probably due to the intrinsic properties of sisal fibers. In general, when the thermosets were reinforced with lignocellulosic fibers, sugarcane bagasse or sisal, they showed satisfactory results of the thermic and mechanical stability. It should be highlighted that composites prepared with high content of material from renewable sources, as the composites reinforced up to 70% fibers and composites with matrix based on 100% lignosulphonate and organosolv lignin, they showed great potential to different applications, such as in the packaging sector and the automotive one, in this case to non-structural applications.

As resinas do tipo fenólica são amplamente utilizadas devido à sua diversidade de aplicações. Considerando as inúmeras vantagens desta resina (estabilidade térmica e dimensional, alta resistência à chama, etc.), este trabalho teve como um dos objetivos melhorar as propriedades mecânicas do termorrígido fenólico, pois estes são frágeis quando não reforçados. Fibras lignocelulósicas naturais foram usadas como reforço no termorrígido fenólico, o que levou a obtenção de biocompósitos. Devido a grande disponibilidade de fibras de bagaço de cana de açúcar no país, como subproduto de agroindústrias, estas fibras foram utilizadas na produção dos compósitos (sendo substituído em até 70% da matriz termorrígida por fibra natural), com a finalidade de atribuir maior valor agregado que o tradicionalmente encontrado para estas fibras. Tendo em vista que atualmente estas fibras podem ser obtidas como resíduo da agroindústria na forma queimada e não queimada, um estudo comparativo foi feito usando ambas as fibras. Compósitos fenólicos foram preparados com as fibras queimadas e não queimadas e os resultados obtidos de resistência ao impacto, módulo de armazenamento e absorção de água mostraram que não há diferenças significativas entre as propriedades de ambos. Considerando estes resultados, a continuidade do trabalho foi realizada com as fibras de bagaço de cana queimado, devido à maior disponibilidade atual destas fibras. Também foram utilizadas fibras de sisal, tradicionalmente conhecidas pelas excelentes propriedades mecânicas e disponibilidade em grande escala no país, para fins comparativos. Adicionalmente, visando aumentar a proporção de uso de matéria prima oriunda de fonte renovável, o lignossulfonato de sódio (NaLS) e lignina organossolve (LO), macromoléculas obtidas a partir de fibras lignocelulósicas, substituíram em 100% o fenol nas reações de obtenção de resinas do tipo resol (obtidas em meio alcalino). Ainda, o formaldeído foi substituído pelo glutaraldeído, um dialdeído, visando-se síntese de resinas alternativas a fenol-formaldeído, tradicionalmente usada. Também, as fibras de bagaço de cana queimadas foram tratadas em solução de NaLS, em banho de ultrassom. Este tratamento foi escolhido por se tratar do uso de macromolécula oriunda de fontes renováveis, assim como pelo fato de a fibra (bagaço de cana) conter alto teor de lignina, o que leva à perspectiva de intensificação da afinidade fibra/agente de tratamento, além de intensificar as interações fibra/matriz, devido à presença de anéis do tipo fenólico em ambas, superfícies das fibras e matriz. As fibras foram caracterizadas quanto à composição química e analisadas via termogravimetria (TG), calorimetria exploratória diferencial (DSC), microscopia eletrônica de varredura (MEV), cromatografia gasosa inversa (IGC), espectroscopia na região de infravermelho (IV), cromatografia liquida de alta performance (HPLC, para determinação do teor de açúcares no bagaço de cana queimado) e difração de raios X. O termorrígido fenólico (não reforçado) e compósitos (matriz fenólica e matrizes baseadas em LO e NaLS reforçados por fibras com distribuição aleatória, em diferentes proporções e comprimentos) foram caracterizados por TG, DSC, IV, MEV, DMTA, resistência ao impacto Izod, resistência à flexão quanto à capacidade de absorção de água. Termorrígidos preparados a base de NaLS apresentaram grande fragilidade após a moldagem, tendo sido apenas submetidos a análises de TG, DSC e cromatografia gasosa inversa (IGC), devido à impossibilidade de realizar outros ensaios. As análises de IGC foram realizadas para fibras e matriz, obtendo-se parâmetros relacionados à energia de superfície e disponibilidade de sítios ácidos e básicos. Os resultados de IGC obtidos para as fibras, tratadas e não tratadas, confirmaram que houve a adsorção do lignossulfonato sódio à superfície destas devido ao aumento de sítios ativos (ácidos e básicos) disponíveis. Os valores de IGC obtidos para as matrizes sugerem que as interações fibra/matriz são favorecidas, principalmente quando o NaLS está presente em ambos os componentes (fibra/matriz). Os resultados obtidos na caracterização dos compósitos indicaram que o lignossulfonato de sódio e a lignina organossolve podem substituir o fenol na formulação de resinas. A utilização de fibras como reforço melhorou as propriedades mecânicas dos materiais, comparativamente aos termorrígidos. Dentre os compósitos preparados com bagaço de cana, a amostra que apresentou melhor desempenho nos ensaios de impacto foram os compósitos de matrizes baseadas em glutaraldeído-LO (112 J m-1) e glutaraldeído-NaLS (82 J m-1). Os compósitos de matriz baseada em formaldeído-NaLS reforçados com fibras de sisal apresentaram melhor desempenho no ensaio de resistência ao impacto (1029 J m-1) e menor quantidade de água absorvida quando imerso em água, comparado aos demais compósitos preparados neste trabalho. As análises de MEV comprovaram a intensificação da adesão entre as fibras de sisal e a matriz, quando esta é preparada a partir de NaLS. Compósitos reforçados com fibras de sisal foram os que apresentaram melhor desempenho mecânico, tanto em resistência ao impacto quanto em flexão, provavelmente devido às propriedades intrínsecas das fibras de sisal. No geral, quando os termorrígidos foram reforçados com as fibras lignocelulósicas, bagaço de cana ou sisal, apresentaram resultados de estabilidade térmica e mecânica satisfatórios. Destaca-se que compósitos preparados com alto teor de material proveniente de fonte renovável, como os compósitos reforçados com até 70% de fibra, e os compósitos com matriz baseada em 100% de lignossulfonato de sódio e lignina organossolve, apresentaram grande potencial para diferentes aplicações, tais como no setor de embalagens e automotivo, neste caso para aplicações não estruturais. / Phenolic resins are widely known due to their diverse applications. Considering the many advantages of this type of resin (flame resistance, thermal and dimensional stability, etc), this study has one objective: the improvement of the mechanical properties of the phenolic thermoset, because this material is fragile when it is not reinforced. Natural lignocellulosic fibers were used as reinforcement in the phenolic thermoset leading to the obtaining of biocomposites. Because the fibers from sugarcane bagasse are byproducts widely available by agricultural industries in this country, these fibers were used in the production of the composites (the thermoset phenolic was replaced by up to 70% natural fibers) - the purpose was to assign greater value than traditionally found for these fibers. Currently, sugarcane fibers can be obtained from natural and burned bagasse. A comparative study was realized using both fibers. Phenolic composites were prepared with the burned fibers and the results obtained from the impact resistance, storage modulus and water absorption showed that they are not significantly different when it comes to the properties of both. Considering these results, the continuity of this study was realized with the burned fibers of sugarcane due to the higher and current availability of this fiber. Lignocellulosic fibers, are traditionally known because of their excellent mechanical properties and wide availability, like the sisal ones used in the present work for comparative reasons. Sisal fibers are available in large scale, facilitating their use. Additionally, sodium lignosulphonate (NaLS) and organosolv lignin (LO), which are macromolecules obtained from the lignocellulosics fibers were used to increase the proportion of the raw materials from renewable sources for a possible phenol substitute in resin reaction, resol type (an alkaline medium). Also, formaldehyde was replaced by glutaraldehyde aiming at the synthesis alternative resin to phenol-formaldehyde, which is traditionally used. Furthermore, burned sugar cane bagasse fibers were treated in NaLS solution, in ultrasonic bath. This treatment was chosen because this macromolecule is from renewable resources and as well as the fibers (sugarcane bagasse) have high content of lignin, which leads to the perspective of affinity intensification between fibers/lignin and fibers/matrix, due to the presence of the aromatics rings in both surfaces. The fibers were characterized in terms of chemical composition and analyzed by thermogravimetry (TG), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), inverse gas chromatography (IGC), infrared spectroscopy (IV), high performance liquid chromatography (HPLC, determination of the sugar content in the burned sugar cane bagasse) and X-ray diffraction. The lignin and resin were characterized by SEC, RMN 1H and RMN 31P. The thermosets (not reinforced) and composites (phenolic matrix and LO and NaLS matrix reinforced with randomly dispersed fibers) were characterized by TG, DSC, IV, Izod impact strength, MEV, flexural strength, DMTA and also the water absorption capacity was evaluated. Thermoset prepared based on NaLS showed great weakness after molding, being submitted only to analysis by TG, DSC and inverse gas chromatography (IGC), due to the impossibility of doing other tests. IGC analysis were realized for fibers and matrix. Parameters related to surface energy and availability of acids and basics sites were obtained. IGC results obtained for the fibers, treated and untreated, confirm that there was adsorption of lignosulphonate in these surfaces due to the increase of available active sites (acids and basics). IGC values obtained for matrix suggest that fiber/matrix interactions are favored, mainly when the NaLS is present in both components (fiber/matrix). The results obtained in the characterization of the composites indicated that lignosulphonate sodium and organosolv lignin can substitute the phenol in the resin formulation. Fibers used as reinforcement improved the mechanical properties of materials, compared to thermosets. Among the composites prepared with sugarcane bagasse, the sample that showed better performance in the impact test were the composites based on glutaraldehyde -LO (112 J m-1) and glutaraldehyde -NaLS (82 J m-1). Composites based on formaldehyde -NaLS reinforced with sisal fibers showed better performance in impact test (1009 J m-1) and less water absorbed when immersed in water, compared to others composites prepared in this study. SEM analysis confirmed the adhesion intensification between the sisal fibers and the matrix, when this is prepared from NaLS. Composites reinforced with sisal fibers showed the best mechanical performance, such as impact strength and flexural strength, probably due to the intrinsic properties of sisal fibers. In general, when the thermosets were reinforced with lignocellulosic fibers, sugarcane bagasse or sisal, they showed satisfactory results of the thermic and mechanical stability. It should be highlighted that composites prepared with high content of material from renewable sources, as the composites reinforced up to 70% fibers and composites with matrix based on 100% lignosulphonate and organosolv lignin, they showed great potential to different applications, such as in the packaging sector and the automotive one, in this case to non-structural applications.

This diploma thesis deals with the development of the rheological properties of plasticized alkali-activated slag over time and depending on the timing of plasticizer and activator addition. These properties are very essential for the use of this material in practice. The main part of this work was oscillating measurements. Two types of measurements were performed – amplitude sweep and time sweep. The aim of the amplitude sweep was to determine the limit properties of the sample related to the destructive structure when the time sweep was continuous monitoring of the evolving structure. Furthermore, calorimetric measurements and solidification measurements were performed using a Vicat apparatus. The silica modulus activator and the method of adding the lignosulfonate-based plasticizer were changed for the individual mixtures. It was found that with the silica module 0 (activation with NaOH) the plasticizer works very well, better results were obtained with the addition of the plasticizer at the beginning of mixing and the activator only later. With increasing silica modulus, the importance of the presence of a plasticizer decreased.