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| Author(s): |
Gilmara de Oliveira Machado
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT) |
| Defense date: | 2000-03-01 |
| Examining board members: |
Agnieszka Joanna Pawlicka;
Adhemar Colla Ruvolo Filho;
Massami Yonashiro
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| Advisor: | Agnieszka Joanna Pawlicka |
| Abstract | |
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. (AU) | |