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Master's Dissertation
DOI
10.11606/D.88.2000.tde-11092001-160555
Document
Author
Full name
Gilmara de Oliveira Machado
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2000
Supervisor
Committee
Pawlicka, Agnieszka Joanna (President)
Ruvolo Filho, Adhemar Colla
Yonashiro, Massami
Title in Portuguese
Preparação e caracterização de CMC e CMC graftizada.
Keywords in Portuguese
CMC graftizada
eletrólito
Abstract in Portuguese
Polpa celulósica, para obtenção de carboximetilcelulose (CMC), foi obtida a partir do bagaço de cana-de-açúcar através de separação do material em fração fibrosa e medula, sua pré-hidrólise, posterior polpação soda/antraquinona e etanol/água. A polpa soda/antraquinona da fração fibra foi submetida ao processo de branqueamento para obter um material rico em celulose de alta pureza. A polpa branqueada da fração fibra foi utilizada na preparação da CMC na forma de sal de sódio e lítio. Para reações de enxertia foram utilizadas amostras de CMC preparadas no laboratório e comerciais usando isocianatos comerciais e sintetizados. Tanto a CMC como a CMC enxertada foram caracterizadas através de análises térmicas (DSC, TGA), espectroscopia no infravermelho (IV), ressonância magnética nuclear de carbono 13 (RMN 13C) e por microscopia eletrônica de varredura (MEV) e Espectroscopia Dispersiva de Raios-X (EDX). A análise detalhada dos espectros de IV e RMN 13C indica a formação de ligações uretanas em diferentes números de onda e deslocamentos químicos dependendo da CMC e isocianato utilizado. Também observa-se uma pequena mudança na linha de base da curva de DSC indicando uma possível transição vítrea da CMC que diminui após a enxertia da CMC com isocianato. Micrografias de MEV mostraram mudanças estruturais com as reações e a análise através de (EDX) um aumento no teor de carbono e diminuição no de oxigênio com as graftizações. Medidas de condutividade demonstraram que a NaCMC graftizada com isocianato de poli(óxido de propileno) apresenta condutividade de 10-5 S/cm a 100oC, comparável com outros eletrólitos sólidos poliméricos
Title in English
Preparation and characterization of CMC and CMC graftized.
Keywords in English
CMC graftized
electrolytes
Abstract in English
The cellulosic pulp obtained from sugar cane bagasse was used to synthesize carboxymethylcellulose (CMC), the substrate for the grafting reactions with mono and di-isocyanathes. The sugar cane bagasse was separated into fiber and non-fiber fractions that then were submitted to the pre-hydrolyses and pulping reactions (sodium hydroxide/anthraquinone and ethanol/water). After that the sodium hydroxide/anthraquinone pulp of the fiber fraction was bleached to obtain a high purity cellulosic material. This cellulose was used to obtain the sodium and lithium salts of CMC (NaCMC and LiCMC respectively). Then these samples were used for grafting reactions with commercial octadecylisocyanate and hexamethylene-diisocyanate and synthesized monoisocyanate of poly(propylene oxide). All the samples were characterized through thermal analyses (DSC/TGA), infra-red spectroscopy (IR), solid state 13C nuclear magnetic resonance (13C-NMR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The thermal analysis indicate a possible glass transition of CMC at about 65oC that decreases for to about 29oC after the grafting reaction with isocyanate. The micrographs show structural changes occurred during the several reactions confirmed by thermal analysis. The detailed analysis of IR and NMR 13C spectra of grafted samples indicated the formation of urethane bonds. Conductivity measurements of NaCMC grafted with the poly(propylene oxide) isocyanate gave the value of 10-5 S/cm at 100oC that is comparable with other polymeric solid electrolytes.
 
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disgilmara.pdf (1.05 Mbytes)
Publishing Date
2002-03-13
 
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