Desenvolvimento e estudo das propriedades em meio aquoso de derivados termorresponsivos da carboximetilcelulose
The present work studies the synthesis and characterization of two copolymers with thermoresponsive properties, consisting of amino terminated poly (ethylene oxide / propylene oxide) grafts in a carboxymethylcellulose (CMC) backbone. Grafting occurred from a coupling reaction between the –NH2 gro...
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| Formato: | Dissertação |
| Idioma: | por |
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/25281 |
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| Resumo: | The present work studies the synthesis and characterization of two copolymers with
thermoresponsive properties, consisting of amino terminated poly (ethylene oxide / propylene
oxide) grafts in a carboxymethylcellulose (CMC) backbone. Grafting occurred from a
coupling reaction between the –NH2 group of the Jeffamine® M-1000 and M-2070
(commercial nomenclature of polyetheramines) with the COOgroups
from CMC, by using 1-
ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as
coupling agents. The structural characterization of the copolymers and their precursors was
done by means of IR and 1H NMR spectroscopy. On the IR spectrum of the copolymers it was
possible to observe the effectiveness of the grafting reaction due to the presence of the amide
group band. In addition, determination of the grafting degree of the Jeffamine chains in the
CMC backbone in both copolymers was possible thru the 1H NMR spectrum, it was obtained
9.52% for CMC-g-Jeffamine® M-1000 and 14.14% for CMC-g-Jeffamine® M-2070. The
behavior in aqueous medium was studied through visual tests, rheological analysis, Dynamic
Light Scattering and UV-vis spectroscopy, the thermo-associative properties of the
synthesized copolymers were verified in saline medium. The CMC-g-Jeffamine® M-1000
copolymer exhibited high apparent viscosity values even in a hostile medium, of high ionic
strength and high temperature conditions. The CMC-g-Jeffamine® M-2070 copolymer also
exhibited the thermoassociative behavior, however its viscosity values are lower than those
achieved by CMC-g-Jeffamine® M-1000 copolymer. |
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