Polímeros e copolímeros hidrossolúveis a base de acrilamida e seus derivados são sintetizados e aplicados principalmente como floculantes, auxiliando na remoção de sólidos finos presentes em águas residuais e industriais. As poliacrilamidas, como são assim chamadas, podem se apresentar em sua forma neutra ou contendo diferentes cargas iônicas (positivas ou negativas) em sua composição em função do tipo de aplicação específica. As poliacrilamidas são sintetizadas, em sua grande maioria, através de emulsões inversas via polimerização radicalar, visando à elevada massa molar do polímero formado. A formulação da poliacrilamida catiônica com fração molar de 0,6 do comonômero iônico foi otimizada através de planejamento fatorial experimental, variando-se os principais fatores de processo: concentração do pacote de surfactante para formação da emulsão inversa, tempo de micronização, concentração de VISCOPLEX® e concentração de ácido graxo. Com base nos resultados obtidos a partir do primeiro planejamento, foram estudadas as seguintes variáveis: HLB do sistema de surfactantes e a troca dos surfactantes monoméricos por surfactantes poliméricos. A otimização da formulação levou em conta principalmente o custo-benefício para produção e comercialização em escala industrial. O fator micronização foi elevado em seu máximo e os fatores VISCOPLEX® e ácido graxo foram excluídos da formulação, após conclusão dos estudos. A troca dos surfactantes monoméricos por poliméricos foi vantajosa devido ao ganho de qualidade do produto final, mesmo com maior custo de implementação. Para minimizar os custos de formulação o fator HLB foi utilizado em seu máximo, onde houve incremento do ALKONAT® L 50 para formação da emulsão inversa. / Acrylamide based hydrosoluble polymers and copolymers and their derivatives are synthesized and mainly applied as flocculants, assisting removal of fine solids present in wastewater and industrial wastewater. Polyacrylamides may be present in their neutral form or with different ionic charges (positive or negative) in their composition depending on the type of specific application. Polyacrylamides are synthesized, mostly by inverse emulsions using radical polymerization, aiming polymers with high molecular weight. Cationic polyacrylamide formulation with 0.6 mole fraction of the ionic comonomer was optimized through design of experiments (DOE), varying the major process factors: surfactant package concentration to form inverse emulsion, micronization time, VISCOPLEX® concentration and fatty acid concentration. Based on the responses from the first DOE, a second DOE was performed, where the variables surfactant system HLB and the exchange of monomeric surfactant by polymeric surfactants were investigated. The formulation optimization considered mainly cost-effective production and industrial scale. The micronization factor was set at its maximum and VISCOPLEX® and fatty acid factors were excluded from the formulation, after conclusion of studies. Exchanging monomeric surfactants by polymeric surfactants led to a final product with higher quality, even considering a higher implementation cost. In order to minimize formulation costs HLB factor was used at its maximum, increasing the content of ALKONAT® L50 to form the inverse emulsion.

Polímeros e copolímeros hidrossolúveis a base de acrilamida e seus derivados são sintetizados e aplicados principalmente como floculantes, auxiliando na remoção de sólidos finos presentes em águas residuais e industriais. As poliacrilamidas, como são assim chamadas, podem se apresentar em sua forma neutra ou contendo diferentes cargas iônicas (positivas ou negativas) em sua composição em função do tipo de aplicação específica. As poliacrilamidas são sintetizadas, em sua grande maioria, através de emulsões inversas via polimerização radicalar, visando à elevada massa molar do polímero formado. A formulação da poliacrilamida catiônica com fração molar de 0,6 do comonômero iônico foi otimizada através de planejamento fatorial experimental, variando-se os principais fatores de processo: concentração do pacote de surfactante para formação da emulsão inversa, tempo de micronização, concentração de VISCOPLEX® e concentração de ácido graxo. Com base nos resultados obtidos a partir do primeiro planejamento, foram estudadas as seguintes variáveis: HLB do sistema de surfactantes e a troca dos surfactantes monoméricos por surfactantes poliméricos. A otimização da formulação levou em conta principalmente o custo-benefício para produção e comercialização em escala industrial. O fator micronização foi elevado em seu máximo e os fatores VISCOPLEX® e ácido graxo foram excluídos da formulação, após conclusão dos estudos. A troca dos surfactantes monoméricos por poliméricos foi vantajosa devido ao ganho de qualidade do produto final, mesmo com maior custo de implementação. Para minimizar os custos de formulação o fator HLB foi utilizado em seu máximo, onde houve incremento do ALKONAT® L 50 para formação da emulsão inversa. / Acrylamide based hydrosoluble polymers and copolymers and their derivatives are synthesized and mainly applied as flocculants, assisting removal of fine solids present in wastewater and industrial wastewater. Polyacrylamides may be present in their neutral form or with different ionic charges (positive or negative) in their composition depending on the type of specific application. Polyacrylamides are synthesized, mostly by inverse emulsions using radical polymerization, aiming polymers with high molecular weight. Cationic polyacrylamide formulation with 0.6 mole fraction of the ionic comonomer was optimized through design of experiments (DOE), varying the major process factors: surfactant package concentration to form inverse emulsion, micronization time, VISCOPLEX® concentration and fatty acid concentration. Based on the responses from the first DOE, a second DOE was performed, where the variables surfactant system HLB and the exchange of monomeric surfactant by polymeric surfactants were investigated. The formulation optimization considered mainly cost-effective production and industrial scale. The micronization factor was set at its maximum and VISCOPLEX® and fatty acid factors were excluded from the formulation, after conclusion of studies. Exchanging monomeric surfactants by polymeric surfactants led to a final product with higher quality, even considering a higher implementation cost. In order to minimize formulation costs HLB factor was used at its maximum, increasing the content of ALKONAT® L50 to form the inverse emulsion.

This is an experimental study into the permeability and compressibility properties of bagasse pulp pads. Three experimental rigs were custom-built for this project. The experimental work is complemented by modelling work. Both the steady-state and dynamic behaviour of pulp pads are evaluated in the experimental and modelling components of this project. Bagasse, the fibrous residue that remains after sugar is extracted from sugarcane, is normally burnt in Australia to generate steam and electricity for the sugar factory. A study into bagasse pulp was motivated by the possibility of making highly value-added pulp products from bagasse for the financial benefit of sugarcane millers and growers. The bagasse pulp and paper industry is a multibillion dollar industry (1). Bagasse pulp could replace eucalypt pulp which is more widely used in the local production of paper products. An opportunity exists for replacing the large quantity of mainly generic paper products imported to Australia. This includes 949,000 tonnes of generic photocopier papers (2). The use of bagasse pulp for paper manufacture is the main application area of interest for this study. Bagasse contains a large quantity of short parenchyma cells called ‘pith’. Around 30% of the shortest fibres are removed from bagasse prior to pulping. Despite the ‘depithing’ operations in conventional bagasse pulp mills, a large amount of pith remains in the pulp. Amongst Australian paper producers there is a perception that the high quantity of short fibres in bagasse pulp leads to poor filtration behaviour at the wet-end of a paper machine. Bagasse pulp’s poor filtration behaviour reduces paper production rates and consequently revenue when compared to paper production using locally made eucalypt pulp. Pulp filtration can be characterised by two interacting factors; permeability and compressibility. Surprisingly, there has previously been very little rigorous investigation into neither bagasse pulp permeability nor compressibility. Only freeness testing of bagasse pulp has been published in the open literature. As a result, this study has focussed on a detailed investigation of the filtration properties of bagasse pulp pads. As part of this investigation, this study investigated three options for improving the permeability and compressibility properties of Australian bagasse pulp pads. Two options for further pre-treating depithed bagasse prior to pulping were considered. Firstly, bagasse was fractionated based on size. Two bagasse fractions were produced, ‘coarse’ and ‘medium’ bagasse fractions. Secondly, bagasse was collected after being processed on two types of juice extraction technology, i.e. from a sugar mill and from a sugar diffuser. Finally one method of post-treating the bagasse pulp was investigated. The effects of chemical additives, which are known to improve freeness, were also assessed for their effect on pulp pad permeability and compressibility. Pre-treated Australian bagasse pulp samples were compared with several benchmark pulp samples. A sample of commonly used kraft Eucalyptus globulus pulp was obtained. A sample of depithed Argentinean bagasse, which is used for commercial paper production, was also obtained. A sample of Australian bagasse which was depithed as per typical factory operations was also produced for benchmarking purposes. The steady-state pulp pad permeability and compressibility parameters were determined experimentally using two purpose-built experimental rigs. In reality, steady-state conditions do not exist on a paper machine. The permeability changes as the sheet compresses over time. Hence, a dynamic model was developed which uses the experimentally determined steady-state permeability and compressibility parameters as inputs. The filtration model was developed with a view to designing pulp processing equipment that is suitable specifically for bagasse pulp. The predicted results of the dynamic model were compared to experimental data. The effectiveness of a polymeric and microparticle chemical additives for improving the retention of short fibres and increasing the drainage rate of a bagasse pulp slurry was determined in a third purpose-built rig; a modified Dynamic Drainage Jar (DDJ). These chemical additives were then used in the making of a pulp pad, and their effect on the steady-state and dynamic permeability and compressibility of bagasse pulp pads was determined. The most important finding from this investigation was that Australian bagasse pulp was produced with higher permeability than eucalypt pulp, despite a higher overall content of short fibres. It is thought this research outcome could enable Australian paper producers to switch from eucalypt pulp to bagasse pulp without sacrificing paper machine productivity. It is thought that two factors contributed to the high permeability of the bagasse pulp pad. Firstly, thicker cell walls of the bagasse pulp fibres resulted in high fibre stiffness. Secondly, the bagasse pulp had a large proportion of fibres longer than 1.3 mm. These attributes helped to reinforce the pulp pad matrix. The steady-state permeability and compressibility parameters for the eucalypt pulp were consistent with those found by previous workers. It was also found that Australian pulp derived from the ‘coarse’ bagasse fraction had higher steady-state permeability than the ‘medium’ fraction. However, there was no difference between bagasse pulp originating from a diffuser or a mill. The bagasse pre-treatment options investigated in this study were not found to affect the steady-state compressibility parameters of a pulp pad. The dynamic filtration model was found to give predictions that were in good agreement with experimental data for pads made from samples of pretreated bagasse pulp, provided at least some pith was removed prior to pulping. Applying vacuum to a pulp slurry in the modified DDJ dramatically reduced the drainage time. At any level of vacuum, bagasse pulp benefitted from chemical additives as quantified by reduced drainage time and increased retention of short fibres. Using the modified DDJ, it was observed that under specific conditions, a benchmark depithed bagasse pulp drained more rapidly than the ‘coarse’ bagasse pulp. In steady-state permeability and compressibility experiments, the addition of chemical additives improved the pad permeability and compressibility of a benchmark bagasse pulp with a high quantity of short fibres. Importantly, this effect was not observed for the ‘coarse’ bagasse pulp. However, dynamic filtration experiments showed that there was also a small observable improvement in filtration for the ‘medium’ bagasse pulp. The mechanism of bagasse pulp pad consolidation appears to be by fibre realignment. Chemical additives assist to lubricate the consolidation process. This study was complemented by pulp physical and chemical property testing and a microscopy study. In addition to its high pulp pad permeability, ‘coarse’ bagasse pulp often (but not always) had superior physical properties than a benchmark depithed bagasse pulp.

Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Joseph B. Schlenoff, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Feb. 1, 2006). Document formatted into pages; contains xvii, 167 pages. Includes bibliographical references.

Die Querstrom-Mikrofiltration mit Kapillarmembranen kommt zunehmend in den Bereichen Lebensmittel-, Pharma-, Chemieindustrie sowie in der Umwelttechnik zum Einsatz. Eine vollständige Beschreibung der Deckschichtbildung innerhalb der Membrananlage ist jedoch noch nicht gelungen. Der erste Teil dieser Arbeit widmet sich der Kuchenbildung in einer Kapillarmembran. Dabei werden sowohl Änderungen der Strömungsverhältnisse entlang der Kapillarlänge als auch Klassiereffekte bei der Querstrom-Mikrofiltration von polydispersen Stoffsystemen berücksichtigt. Die Modellberechnungen wurden mit Experimenten validiert. Weiterhin erfolgte die Untersuchung des Einflusses von polymeren Flockungsmitteln (PFM) auf die Mikrofiltration und der Möglichkeiten einer Filtratstromerhöhung durch Flockung mittels PFM. Es wird gezeigt, dass eine optimale Zudosierung von PFM existiert und diese mit einer maximalen Filtratstromerhöhung verbunden ist. Eine Überdosierung von PFM soll jedoch verhindert werden.

This diploma thesis will discuss possibilities of using nanofibres to increase the strenght of the brick body, replacement of the current schrinkage reducing agent – quartz sand by stone dust, the use of flocculants as pore-forming agent and coloration of the body using iron trioxide.

Die Querstrom-Mikrofiltration mit Kapillarmembranen kommt zunehmend in den Bereichen Lebensmittel-, Pharma-, Chemieindustrie sowie in der Umwelttechnik zum Einsatz. Eine vollständige Beschreibung der Deckschichtbildung innerhalb der Membrananlage ist jedoch noch nicht gelungen. Der erste Teil dieser Arbeit widmet sich der Kuchenbildung in einer Kapillarmembran. Dabei werden sowohl Änderungen der Strömungsverhältnisse entlang der Kapillarlänge als auch Klassiereffekte bei der Querstrom-Mikrofiltration von polydispersen Stoffsystemen berücksichtigt. Die Modellberechnungen wurden mit Experimenten validiert. Weiterhin erfolgte die Untersuchung des Einflusses von polymeren Flockungsmitteln (PFM) auf die Mikrofiltration und der Möglichkeiten einer Filtratstromerhöhung durch Flockung mittels PFM. Es wird gezeigt, dass eine optimale Zudosierung von PFM existiert und diese mit einer maximalen Filtratstromerhöhung verbunden ist. Eine Überdosierung von PFM soll jedoch verhindert werden.