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Previous issue date: 2011-07-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Gels consist of soft materials with vast use in several activities, such as in
pharmaceutical industry, food science, and coatings/textile applications. In order to obtain
these materials, the process of gelification, that can be physical (based on physical
interactions) and/or chemical (based on covalent crosslinking), has to be carried out. In this
work we used dynamic light scattering (DLS) and rheometry to monitor the covalent
gelification of chitosan solutions by glutaraldehyde. Intensity correlation function (ICF) data
was obtained from DLS and the exponential stretched Kohrausch-William-Watts function
(KWW) was fitted to them. The parameters of the KWW equation, β, Γ and C were evaluated.
These methods were effective in clarifying the process of sol-gel transition, with the
emergence of non-ergodicity, and determining the range of gelation observed in about 10-20
minutes. The dependence between apparent viscosity on reaction time was used to support the
discussion proposed. / G?is s?o materiais que possuem aplica??es em v?rias ?reas, tais quais, na ind?stria de
tintas, alimentos e farmac?utica. Os m?todos empregados para obten??o dos g?is podem ser
f?sicos (intera??es f?sicas) e/ou qu?micos (baseado em intera??es covalentes), tal processo, ?
denominado gelifica??o. Neste trabalho, o processo de gelifica??o de quitosana/glutaralde?do
foi monitorado utilizando reometria e espalhamento da luz (DLS). As fun??es de correla??o
de intensidade (ICF) foram obtidas atrav?s de DLS e a equa??o de Kohrausch-William-Watts
(KWW) foi ajustada com os dados experimentais. Os par?metros da equa??o KWW, β, Γ e C
foram avaliados. Estes m?todos foram eficazes na clarifica??o do processo que compreende a
transi??o sol-gel, com o surgimento da n?o-ergodicidade, e na determina??o da faixa de
gelifica??o, observada em torno de 10-20 minutos. A depend?ncia da viscosidade aparente em
fun??o do tempo foi utilizada para comprovar o tempo de gelifica??o observado no DLS.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17649 |
| Date | 20 July 2011 |
| Creators | Morais, Wildson Arcanjo de |
| Contributors | CPF:90623207753, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788562T6, Wanderley Neto, Alcides de Oliveira, CPF:00738841463, http://lattes.cnpq.br/4789528535524269, Vasconcelos, Cl?udio Lopes de, CPF:02963319452, http://lattes.cnpq.br/7657769529479698, Fonseca, Jos? Luis Cardozo |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Qu?mica, UFRN, BR, F?sico-Qu?mica; Qu?mica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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