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The epoxy resin system based on tetraglycidyldiaminodiphenyl- methane (TGDDM) and diaminodiphenylsulfone (DDS) is widely used for high performance aerospace applications. The desirable macroscopic properties of the TGDDM/DDS resin are dependant upon the microscopic network formed during resin curing, but to date work aimed at clarifying the structure of this network has proved inconclusive. This work further investigates the epoxy resin network structure, using the techniques of isotopic labelling and solid state nuclear magnetic resonance (NMR).The synthesis of labelled TGDDM and DDS by known and original protocols has been investigated. A majority of the work was aimed at the unambiguous labelling with carbon-13 and deuterium of TGDDM, the success of which has led to the discovery of a versatile and convenient method of labelling epichlorohydrin. Nitrogen-15 labelled TGDDM and DDS were also synthesised, the latter using an original protocol. Cured epoxy resins containing isotopic labels were produced, and investigated using solid state NMR. The presence of both linear and cyclised structures was observed, and their relative contributions to the network estimated. Unambiguous assignment of the solid state NMR spectrum was also made. Finally, using samples and methodologies from the isotopic labelling syntheses, further small scale studies were carried out. A range of a-ketosulfonate compounds was synthesised to probe the formation reaction. The crystal structures of three related compounds containing different halogen substituents were compared. Two further epoxide compounds were synthesised and evaluated as potential epoxy resin additives. A bis-a-chloroketone was evaluated as a substrate for baker’s yeast reduction, and yielded a diol with a high enantiomeric excess.

Thesis (M. S.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2007. / Koros, William, Committee Member ; Hsieh, Jeffery, Committee Chair ; Deng, Yulin, Committee Member.

É crescente o aumento da preocupação do homem com a contaminação de ambientes aquáticos uma vez que da subsistência dos mesmos depende o bem estar de todos. Ao mesmo tempo em que cresce a preocupação tem aumentado a quantidade de pesquisas em busca de tecnologias alternativas ao tratamento e remediação de efluentes aquosos contaminados pelas mais diversas substâncias incluindo os metais pesados. Nas últimas décadas, tem crescido o número de trabalhos avaliando a capacidade de sorção e a viabilidade da utilização de biossorventes de baixo custo na captação de íons metálicos e um desses materiais são as biomassas de algas pardas. Dentre os vários gêneros existentes no planeta o território brasileiro é rico na macroalga do gênero Sargassum. Muito embora a composição dessas biomassas varie o principal constituinte das mesmas é o ácido algínico e seus sais alcalinos na forma de um copolímero linear, homopolimérico, com unidades do ácido manurônico, (M), (1-4)-β-D- ligado e seu epímero em C-5 nos resíduos α-L-gulurônicos, (G), respectivamente, covalentemente ligados entre si em sequencias diferenciadas ou em blocos. Os monômeros podem aparecer em blocos homopoliméricos consecutivos, resíduos G (unidades G), resíduos consecutivos M (unidades M), pequenas unidades alternadas M e G (blocos MG), ou em blocos aleatoriamente organizados. A proposta dessa dissertação é realizar a modificação do copolímero existente na biomassa com epicloridrina, avaliar e comparar a captação de íons Cu (II) e Hg (II) pela biomassa da alga Sargassum sp., com a biomassa não modificada e resultados publicados na literatura / A growing concern of increasing the man with the contamination of aquatic environments since the livelihoods of those dependent on the welfare of all. While growing concern has increased the amount of research in search of alternative treatment technologies and remediation of aqueous waste streams contaminated by various substances including heavy metals. In recent decades, has increased the number of reports assessing the sorption capacity and the feasibility of using low-cost biosorbent uptake of metal ions and these materials are the biomass of brown algae. Among the various genres on the planet Brazilian territory is rich in macro algae of the genus Sargassum. Although the composition of these biomasses vary the main constituent of these images is alginic acid and alkaline salts in the form of a linear copolymer, homopolymeric blocks of (1-4)-linked β-D mannuronic acid (M), and its C-5 epimer α-L-guluronic, (G) residues, respectively, covalently linked together in different sequences or blocks. The monomers can appear in homopolymeric block of consecutive G-residues (G-blocks), consecutive M-residues (M-blocks), alternating M and G (MG blocks) or randomly organized blocks. The purpose of this dissertation is the modification of existing biomass copolymer with epichlorohydrin, evaluate and compare the uptake of Cu (II) and Hg (II) by biomass of seaweed Sargassum sp. with the unmodified biomass and results published in literature

Non-ionic copolymers, such as poly(1-vinylpyrrolidone-co-styrene), are used in the production of filtration membranes and fibers because of their ability to provide both hydrophilic and hydrophobic character. However, their non-ionic character and solubility in water prevents inexpensive recovery from waste streams. Wood fibers show potential as recovery agents because they are inexpensive, environmentally friendly, and have a large surface area per unit mass (200 m2/g). However, due to the anionic nature of the fiber surface, their adsorptive behavior is often limited to cationic species. We have shown that low-dosage application of a cationic polyamide epichlorohydrin resin, Kymene 557H®, using a sequential adsorption process can alter the fiber surface charge so as to provide more neutral surface area for the non-ionic polymer to adsorb; furthermore, the adsorbed Kymene 557H® does not block the approach of poly(1-vinylpyrrolidone-co-styrene). Single-component adsorption of poly(1-vinylpyrrolidone-co-styrene) was on the order of 10-3 g/g; with Kymene 557H® adsorbed on the fiber, the adsorption increased one order of magnitude to 10-2 g/g. This significant increase is caused by neutralization of fiber surface charge via Kymene 557H® adsorption, creating a surface more favorable for adsorption and recovery of non-ionic species.

É crescente o aumento da preocupação do homem com a contaminação de ambientes aquáticos uma vez que da subsistência dos mesmos depende o bem estar de todos. Ao mesmo tempo em que cresce a preocupação tem aumentado a quantidade de pesquisas em busca de tecnologias alternativas ao tratamento e remediação de efluentes aquosos contaminados pelas mais diversas substâncias incluindo os metais pesados. Nas últimas décadas, tem crescido o número de trabalhos avaliando a capacidade de sorção e a viabilidade da utilização de biossorventes de baixo custo na captação de íons metálicos e um desses materiais são as biomassas de algas pardas. Dentre os vários gêneros existentes no planeta o território brasileiro é rico na macroalga do gênero Sargassum. Muito embora a composição dessas biomassas varie o principal constituinte das mesmas é o ácido algínico e seus sais alcalinos na forma de um copolímero linear, homopolimérico, com unidades do ácido manurônico, (M), (1-4)-β-D- ligado e seu epímero em C-5 nos resíduos α-L-gulurônicos, (G), respectivamente, covalentemente ligados entre si em sequencias diferenciadas ou em blocos. Os monômeros podem aparecer em blocos homopoliméricos consecutivos, resíduos G (unidades G), resíduos consecutivos M (unidades M), pequenas unidades alternadas M e G (blocos MG), ou em blocos aleatoriamente organizados. A proposta dessa dissertação é realizar a modificação do copolímero existente na biomassa com epicloridrina, avaliar e comparar a captação de íons Cu (II) e Hg (II) pela biomassa da alga Sargassum sp., com a biomassa não modificada e resultados publicados na literatura / A growing concern of increasing the man with the contamination of aquatic environments since the livelihoods of those dependent on the welfare of all. While growing concern has increased the amount of research in search of alternative treatment technologies and remediation of aqueous waste streams contaminated by various substances including heavy metals. In recent decades, has increased the number of reports assessing the sorption capacity and the feasibility of using low-cost biosorbent uptake of metal ions and these materials are the biomass of brown algae. Among the various genres on the planet Brazilian territory is rich in macro algae of the genus Sargassum. Although the composition of these biomasses vary the main constituent of these images is alginic acid and alkaline salts in the form of a linear copolymer, homopolymeric blocks of (1-4)-linked β-D mannuronic acid (M), and its C-5 epimer α-L-guluronic, (G) residues, respectively, covalently linked together in different sequences or blocks. The monomers can appear in homopolymeric block of consecutive G-residues (G-blocks), consecutive M-residues (M-blocks), alternating M and G (MG blocks) or randomly organized blocks. The purpose of this dissertation is the modification of existing biomass copolymer with epichlorohydrin, evaluate and compare the uptake of Cu (II) and Hg (II) by biomass of seaweed Sargassum sp. with the unmodified biomass and results published in literature

Orientador: Florencia Cecilia Menegalli, Paulo Jose do Amaral Sobral / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T12:22:15Z (GMT). No. of bitstreams: 1 Elizondo_NadiaridJimenez_M.pdf: 2126194 bytes, checksum: 4acc5f16861afb60bd2c79a07a290f4d (MD5) Previous issue date: 2007 / Resumo: O amaranto apresenta-se como uma matéria prima interessante para a elaboração de filmes biodegradáveis por seu conteúdo em amido, proteína e lipídeos. Embora o amaranto não seja nativo do Brasil, seu cultivo está sendo desenvolvido nos solos dos cerrados brasileiros com bons resultados. Isto incentiva o desenvolvimento de alternativas para o uso comercial do amaranto. Filmes elaborados a partir de amaranto da variedade caudatus (TAPIA-BLÁCIDO, 2003) resultaram em materiais com excelentes propriedades de barreira, entretanto apresentaram propriedades mecânicas pobres. Estudos desenvolvidos com a variedade que está sendo implantada no Brasil (Amarantus cruentus) com adição de ácido esteárico apresentaram as mesmas características (COLLA, 2004). Assim, o objetivo desta pesquisa foi o estudo do processo de elaboração de dois tipos de filmes biodegradáveis: (1) filmes de farinha de amaranto (A.cruentus) reticulados com epicloridrina e (2) a partir de blendas de farinha de amaranto (A.cruentus) com poli (vinil álcool) (PVA); assim como a avaliação do efeito das duas estratégias (reticulação e PVA) sobre as características mecânicas e de barreira dos biofilmes. O efeito da reação de reticulação (concentração de epicloridrina (1,6-18,4 g/100g farinha), temperatura (39,8-90,2ºC) e tempo de reação (12,8-147,2 minutos)) sobre as propriedades mecânicas e de barreira, foram estudados utilizando a metodologia de superfície de resposta. Para a caracterização dos biofilmes, foram realizadas as seguintes análises: testes mecânicos, de solubilidade em água, de permeabilidade ao vapor de água, microscopia eletrônica de varredura e espectroscopia de infravermelho com transformada de Fourier (FT-IR). Para os filmes de farinha de amaranto reticulados com epicloridrina, de acordo com a análise estatística das superfícies de resposta, foi observado que a reação de reticulação teve um efeito plasticizante sobre os filmes de farinha de amaranto, ao diminuir a resistência e aumentar a flexibilidade dos mesmos. Além disso, foi evidenciado o forte impacto que tem a temperatura de reação sobre a solubilidade dos filmes, já que ao aumentar a temperatura, aumentou a solubilidade em água, e diminui o pH da solução filmogênica. Foi assim como foram realizadas uma série de reações com temperatura (39,8ºC) e tempo (120 min) fixos, e diferentes concentrações de epicloridrina (1,6-18,4 g/100g farinha). Nestas condições os filmes reticulados não apresentaram diferença significativa (p<0,05) nas propriedades mecânicas em relação ao filme de farinha de amaranto não modificado. Mesmo assim, a reticulação melhorou as propriedades de barreira do filme, com uma diminuição considerável da permeabilidade ao vapor de água (PVAmédia = 2,3 x 10-10 g / m s Pa). Além disso, a reticulação reduziu a solubilidade em água (Smédia = 29%) e manteve a integridade dos filmes durante o teste. A análise do FTIR mostrou evidência de modificações químicas nos filmes de farinha de amaranto reticulados com epicloridrina. Além disso, as imagens de MEV deram indícios do efeito que a reação de reticulação com epicloridrina teve sobre a microestrutura dos filmes de farinha de amaranto. Para os biofilmes a partir de blendas de farinha de amaranto com PVA, foram testados seis tipos de PVA com diferentes graus de hidrólise e peso molecular, foi escolhido o PVA 325 por apresentar as melhores propriedades mecânicas (Tensão (TS) 10,21MPa, Elongação (ELO) 89,76%, Força (PF) 9,40N e Deformação (PD) 16,3%). Quando foram avaliadas várias proporções da mistura, farinha de amaranto ¿ PVA (10- 50%) foi observado que as propriedades mecânicas, tanto a resistência quanto a flexibilidade, foram aumentadas ao incrementar a concentração de PVA na blenda, os valores foram pelo menos dobrados. A solubilidade em água foi diminuída ao aumentar a proporção de PVA na mistura, até atingir 44% de matéria solúvel para o filme com iguais proporções de farinha ¿ PVA. A análise do FT-IR confirmou a formação de pontes de hidrogênio entre os componentes dos filmes a partir de blendas de farinha de amaranto e poli(vinil álcool) / Abstract: The amaranth is an interesting material for biodegradable films production because it contains starch, protein and lipids. Although the amaranth is not native of Brazil, its culture is being developed in Brazilian ground with good results. This stimulates the development of commercial use of amaranth alternatives. Films elaborated from amaranth of the caudatus variety (TAPIA-BLÁCIDO, 2003) had resulted in materials with excellent barrier properties, but presented poor mechanical properties. Studies developed with the Brazilian cultivated variety (Amaranthus cruentus) with addition of stearic acid had presented the same characteristics (COLLA, 2004). Therefore, the research objective was to study the elaboration process of two types of biodegradable films: (1) Amaranth (A.cruentus) flour films crosslinked with epichlorohydrin, and (2) Amaranth (A.cruentus) flour films blended with poly(vinyl alcohol) (PVA); as well as to evaluate the effect of both strategies (crosslinking and PVA addition) on the mechanical and barrier characteristics of the films. The effect of the crosslinking reaction (epichlorohydrin concentration (1.6-18.4 g/100g flour), temperature (39.8-90.2ºC) and time (12.8-147.2 minutes)) on the mechanical and barrier properties was studied using the response surface methodology (RSM). For the biofilms characterization, the following essays were carried out: mechanical tests, solubility in water, water vapor permeability, scanning electron microscopy (SEM), and Fourier transformed infrared spectroscopy (FT-IR). The statistics analysis (RSM) for amaranth flour films crosslinked with epichlorohydrin, showed that the crosslinking reaction provided a plasticizing effect on the A.cruentus flour films, as it reduced the resistance and increased the flexibility of crosslinked films. Moreover, it was evident the strong impact that the reaction temperature had on the films solubility: at high reaction temperatures, the solubility in water increased, and the pH of the solution decreased. Thus, a series of crosslinking reactions with fixed temperature (39.8ºC) and time (120 min), and different epichlorohydrin concentrations (1.6-18.4 g/100g flour) were developed. Under these conditions the crosslinking reaction did not improve the mechanical performance of the A.cruentus flour films. However, it considerably reduced the solubility in water (Saverage = 29%) and the water vapor permeability (WVPaverage = 2.3 x 10-10 g / m s Pa) of the crosslinked films. It also maintained the film integrity during solubility test. FT-IR analysis showed evidence of chemical modification in the crosslinked A.cruentus flour films. SEM micrographs demonstrated the effect of the crosslinking reaction on the film microstructure. Six types of PVA with different hydrolysis degrees and molecular weight were tested for biofilms from amaranth flour blended with PVA. PVA 325 was chosen due to it superior mechanical performance (TS 10.21MPa, ELO 89.76%, PF 9.40N and PD 16.3%). When blended films of amaranth flour - PVA (10-50%) were evaluated, all mechanical properties (TS, ELO, PF and PD) were enhanced as the PVA 325 content was increased, values were at least doubled. The solubility in water (S) of the blended films decreased as the PVA content increased; reaching 44% of soluble mater for equal proportion blended film. The formation of hydrogen bonds between the blend components was confirmed by the FT-IR spectra analysis / Mestrado / Mestre em Engenharia de Alimentos

Le travail présenté dans ce manuscrit s’intéresse au mode d’action des résines thermodurcissables utilisées pour conférer au matériau papier des propriétés spécifiques. En effet, certains papiers sont destinés, au cours de leur usage, à être en contact avec des liquides et en particulier de l’eau. C’est le cas, par exemple, des papiers absorbants, de certains papiers filtres, mais aussi de papiers pour étiquettes ou pour billets de banque. En présence d’eau, les papiers perdent rapidement leur résistance mécanique, essentiellement due à la présence en grand nombre de liaisons hydrogène, d’où la nécessité d’un traitement : l’objectif est de maintenir un certain niveau de résistance des papiers saturés en eau. Ces traitements consistent à introduire dans la suspension fibreuse, en cours d’élaboration, des pré-polymères cationiques s’adsorbant à la surface des fibres. Après la formation de la feuille de papier, la feuille humide est séchée et c’est au cours de cette étape que s’amorce la réticulation de ces polymères. Elle conduit à la formation d’un réseau tridimensionnel de polymère dans le matelas fibreux. Ce réseau permet au papier de conserver ses propriétés mécaniques lorsqu’il est en contact avec de l’eau. Il présente ce que l’on appelle communément une résistance à l’état humide (REH). Un des inconvénients de ce type de traitement est lié aux difficultés de recyclage des papiers obtenus. Il nécessite un traitement particulièrement intensif et coûteux qui couple une action mécanique (désintégration, dépastillage) à une action chimique (utilisation d’hydroxyde de sodium, par exemple). Même si ces produits sont largement utilisés, les mécanismes mis en jeu que ce soit pour le développement des propriétés de REH ou pour le recyclage ne sont pas totalement compris. Dans ce contexte, ce travail a pour objectif d’étudier le mode d’action de pré-polymères de polyamideamine épichlorhydrine (PAE), couramment utilisés en papeterie pour conférer au matériau papier une résistance à l’état humide (REH). Il s’intéresse à la caractérisation de solutions commerciales de PAE et à l’étude des mécanismes réactionnels de ces pré-polymères. Il traite également de l’effet de certains paramètres de production du papier sur l’efficacité des traitements. Enfin, il apporte de éléments nouveaux sur la compréhension de l’étape de recyclage. / Polyamideamine epichlorohydrin (PAE) resin is a water soluble additive and the most used permanent wet strength additive in alkaline conditions for preparing wet strengthened papers. In this thesis, we studied some properties of PAE resins and wet strengthened papers prepared from them. In order to elucidate PAE structure, liquid state, 1H and 13C NMR was performed and permitted signals assignment of PAE structure. PAE films were prepared to study cross-linking reactions and then thermal and ageing treatments were performed. According to our results, the main PAE cross-linking reaction occurs by a nucleophilic attack of N atoms in the PAE and/or polyamideamine structures forming 2-propanol bridges between PAE macromolecules. A secondary contribution of ester linkages to the PAE cross-linking was also observed. However, this reaction, which is thermally induced, only occurs under anhydrous conditions. The mechanism related to wet strength development of PAE-based papers was studied by using CMC as a model compound for cellulosic fibres and PAE-CMC interactions as a model for PAE-fibres interactions. Based on results from NMR and FTIR, we clearly showed that PAE react with CMC that is when carboxylic groups are present in great amounts. Consequently, as the number of carboxylic groups present in lignocellulosic fibres is considerably less important and the resulting formed ester bonds are hydrolysable, we postulate that ester bond formation has a negligible impact on the wet strength of PAE-based papers. In the second part of this work, a 100% Eucalyptus pulp suspension was used to prepare PAE-based papers. PAE was added at different dosages (0.4, 0.6 and 1%) into the pulp suspension and its adsorption was indirectly followed by measuring the zeta potential. Results indicate that the adsorption, reconformation and/or penetration phenomena reach an apparent equilibrium between 10 and 30 min. Moreover, we showed that the paper dry strength was not significantly affected by the conductivity level (from 100 to 3000 µS/cm) of the pulp suspension. However, the conductivity has an impact on the wet strength and this effect seems to be enhanced for the highest PAE dosage (1%). We also demonstrated that storing the treated paper under controlled conditions or boosting the PAE cross-linking with a thermal post-treatment does not necessarily lead to the same wet strength. Degrading studies of cross-linked PAE films showed that PAE degradation in a persulfate solution at alkaline medium was more effective. A preliminary study of industrial PAE-based papers (coated and uncoated papers) was also performed. For uncoated paper, persulfate treatment was the most efficient. For coated papers, all treatments were inefficient in the used conditions, although a decrease of the wet tensile force of degraded samples was observed. The main responsible of the decrease of persulfate efficiency for coated papers was probably related to side reactions of free radicals with the coating constituents.

L'association d'halogénure de tétraoctylammonium et de triisobutylaluminium permet de réaliser la polymérisation anionique de divers époxydes par activation du monomère. Ces systèmes catalytiques ont été appliqués à la (co)polymérisation de l'épichlorhydrine. Cette méthode qui a permis d'obtenir des poly(épichlorhydrine)s de masses molaires contrôlées jusqu'à 100 000 g/mol, a été étendue ensuite à la synthèse de copolymères, statistiques et à blocs, associant l'épichlorhydrine à divers oxiranes substitués : oxyde de propylène, éther tert-butyl glycidique et éther allyl glycidique. Dans le but d'élargir le domaine d'application de ces polyéthers ω-hydroxylés, l'introduction de groupements fonctionnels en tête de chaine a été étudiée. L'influence des substituants du dérivé aluminique et la nature de l'amorceur sur l'efficacité et la spécificité de l'amorçage ont été examinés. / Association of tetraoctylammonium halide and triisobutylaluminium allows anionic polymerization of epoxides by an activated monomer mechanism. This catalytic system was applied to the synthesis of (co)polymers of epichlorohydrin. The synthesis of poly(epichlorohydrin) was achieved in a controlled manner allowing the preparation of polymers with molar masses up to 100 000 g/mol. This approach was extended to the synthesis of statistic and block copolymers of epichlorohydrin with various substituted oxirane : propylene oxide, tert-butyl glycidyl ether and allyl glycidyl ether.In order to extend the application field of this ω-hydroxyl polyether, we have investigated the introduction of functional groups at the beginning of the polymer chain. For this purpose, the influence of the substituted group on the aluminium and the nature of the initiator were examined on the efficiency and the specificity of the initiation step.

No description available.