Preparação e caracterização de derivados celulósicos obtidos a partir da celulose bacteriana e obtenção de filmes para aplicações óticas
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Data
2013-04-29
Autores
Oliveira, Rafael Leite de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Esta tese apresenta a preparação e caracterização de derivados de celulose e também de novos materiais multifuncionais baseados na celulose produzida pela bactéria Gluconacetobacter xylinus e nos seus derivados respectivamente. A celulose bacteriana (CB) possui fórmula molecular idêntica a celulose de plantas (CP) e apresenta uma estrutura de nanofios de celulose dispostos numa rede tridimensional. Membranas secas foram utilizadas para a preparação dos derivados celulósicos. Foram obtidos os derivados acetato de celulose (AC), celulose microcristalina (MCC), carboximetilcelulose (CMC) e metilcelulose (MC). O AC apresentou valores de grau de substituição (GS) que foram de 2,3 a 2,8 e solubilidade em acetona ou diclorometano (dependendo do GS). A MCC foi obtida como um pó fino na cor marfim com grau de polimerização em torno de 200 unidades de anidroglucose (AGU), com a vantagem de que nas suas partículas ainda apresenta uma memória da rede tridimensional da CB. Foram obtidos CMCs com GS de 0,1 a 0,8 e com excelente solubilidade em água. Finalmente foram obtidas amostras de MC, com GS de 0,54 para a síntese em iodometano e 2,3 para a síntese em dimetilsulfato (DMS), com boa solubilidade em água. Os derivados, de acordo com suas propriedades e sua solubilidade foram utilizados para a preparação e caracterização de novos materiais na área de aplicações óticas. As membranas de AC,CMC e CB foram utilizados como substratos para a preparação de dispositivos flexíveis de emissão de luz, FOLEDs (Flexible Organic Light Emitting Diodes). Os substratos foram recobertos com um filme fino de ITO. Os FOLEDs foram então obtidos pela deposição de filmes orgânicos por evaporação térmica, na seguinte sequencia: ftalocianina de cobre (CuPC)/ N,N’-difenil-N,N’-bis(1-naftil) (1,1’bifenil)-4,4’diamina (NPB)...
This thesis presents the preparation and characterization of cellulose derivatives and also new multifunctional materials based on cellulose produced by bacteria Gluconacetobacter xylinus and their derivatives respectively. Bacterial cellulose (BC) shows molecular formula identical to plant cellulose (PC) and a three-dimensional cellulose nanowires network. Dried membranes were used for the preparation of cellulose derivatives. The derivatives cellulose acetate, microcrystalline cellulose, carboxymethylcellulose and methylcellulose were obtained. The AC showed values of degree of substitution (DS) of 2.3 to 2.8 and soluble in acetone or dichloromethane. The MCC was obtained as an ivory colored fine powder with degree of polymerization around 200 anhydroglucose units (AGU), with the advantage that particles still present in its memory the three-dimensional network of CB. CMCs were obtained with GS 0.1 to 0.8 and has excellent water solubility. Finally samples of MC were obtained with DS of 0.54 to 2.3 from iodomethane and dimethyl sulfate synthesis respectively, with good water solubility. The derivatives (according to their properties and their solubility) were used for the preparation and characterization of new materials in the field of optical applications. The cellulose acetate and bacterial cellulose membranes were used as substrates for the preparation of flexible devices for light emission, FOLEDs. The substrates were coated with thin films of ITO. FOLEDs were obtained by thermal evaporation, in the following sequence: copper phthalocyanine (CuPc) /(N,N΄-bis(1- naphtyl)- N,N΄-diphenyl-1,1´-biphenyl-4,4´-diamine) (NPB) /tris(8-hydroxyquinoline) aluminum and the aluminum contact. The total maximum luminance values for the FOLED was 530 (cd/m2), which is comparable with a glass OLED prepared with... (Complete abstract click electronic access below)
This thesis presents the preparation and characterization of cellulose derivatives and also new multifunctional materials based on cellulose produced by bacteria Gluconacetobacter xylinus and their derivatives respectively. Bacterial cellulose (BC) shows molecular formula identical to plant cellulose (PC) and a three-dimensional cellulose nanowires network. Dried membranes were used for the preparation of cellulose derivatives. The derivatives cellulose acetate, microcrystalline cellulose, carboxymethylcellulose and methylcellulose were obtained. The AC showed values of degree of substitution (DS) of 2.3 to 2.8 and soluble in acetone or dichloromethane. The MCC was obtained as an ivory colored fine powder with degree of polymerization around 200 anhydroglucose units (AGU), with the advantage that particles still present in its memory the three-dimensional network of CB. CMCs were obtained with GS 0.1 to 0.8 and has excellent water solubility. Finally samples of MC were obtained with DS of 0.54 to 2.3 from iodomethane and dimethyl sulfate synthesis respectively, with good water solubility. The derivatives (according to their properties and their solubility) were used for the preparation and characterization of new materials in the field of optical applications. The cellulose acetate and bacterial cellulose membranes were used as substrates for the preparation of flexible devices for light emission, FOLEDs. The substrates were coated with thin films of ITO. FOLEDs were obtained by thermal evaporation, in the following sequence: copper phthalocyanine (CuPc) /(N,N΄-bis(1- naphtyl)- N,N΄-diphenyl-1,1´-biphenyl-4,4´-diamine) (NPB) /tris(8-hydroxyquinoline) aluminum and the aluminum contact. The total maximum luminance values for the FOLED was 530 (cd/m2), which is comparable with a glass OLED prepared with... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Química inorgânica, Celulose, Acetatos, Cellulose
Como citar
OLIVEIRA, Rafael Leite de. Preparação e caracterização de derivados celulósicos obtidos a partir da celulose bacteriana e obtenção de filmes para aplicações óticas. 2013. 176 f. Tese (doutorado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Química de Araraquara, 2013.