Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous medium
<abstract language="eng">Chitosan was acetylated during 2, 5 and 10h and physical gels were obtained at different polymer concentrations in N,N-dimethylacetamide containing 5% of LiCl. Acetylation was confirmed by infrared spectroscopy and 13C NMR, and degrees of acetylation in the r...
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| Format: | Article |
| Language: | English |
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Sociedade Brasileira de Química
2008-01-01
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| Series: | Química Nova |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422008000300004 |
| _version_ | 1818670073962823680 |
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| author | Rosangela Balaban Garcia Dayse Luzia Pinheiro da Silva Marta Costa Fernanda Nervo Raffin Naira Machado da Silva Ruiz |
| author_facet | Rosangela Balaban Garcia Dayse Luzia Pinheiro da Silva Marta Costa Fernanda Nervo Raffin Naira Machado da Silva Ruiz |
| author_sort | Rosangela Balaban Garcia |
| collection | DOAJ |
| description | <abstract language="eng">Chitosan was acetylated during 2, 5 and 10h and physical gels were obtained at different polymer concentrations in N,N-dimethylacetamide containing 5% of LiCl. Acetylation was confirmed by infrared spectroscopy and 13C NMR, and degrees of acetylation in the range of 0.82-0.91 were determined by NMR. The O-acetylation degree (0.12-0.15) was exclusively determined by a volumetric method. Rheological studies showed that the storage modulus values were smaller for the more acetylated samples and increased with the temperature and the polymer concentration. All the gels presented storage modulus superior to loss modulus, evidencing more elastic than viscous characteristics. The results obtained in this work suggest a gelation process based on a balance between O and N-acetylation and intermolecular bonds. |
| first_indexed | 2024-12-17T07:02:19Z |
| format | Article |
| id | doaj.art-882932f4e1bf40f58d6e15353f7b33a5 |
| institution | Directory Open Access Journal |
| issn | 0100-4042 1678-7064 |
| language | English |
| last_indexed | 2024-12-17T07:02:19Z |
| publishDate | 2008-01-01 |
| publisher | Sociedade Brasileira de Química |
| record_format | Article |
| series | Química Nova |
| spelling | doaj.art-882932f4e1bf40f58d6e15353f7b33a52022-12-21T21:59:14ZengSociedade Brasileira de QuímicaQuímica Nova0100-40421678-70642008-01-0131348649210.1590/S0100-40422008000300004Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous mediumRosangela Balaban GarciaDayse Luzia Pinheiro da SilvaMarta CostaFernanda Nervo RaffinNaira Machado da Silva Ruiz<abstract language="eng">Chitosan was acetylated during 2, 5 and 10h and physical gels were obtained at different polymer concentrations in N,N-dimethylacetamide containing 5% of LiCl. Acetylation was confirmed by infrared spectroscopy and 13C NMR, and degrees of acetylation in the range of 0.82-0.91 were determined by NMR. The O-acetylation degree (0.12-0.15) was exclusively determined by a volumetric method. Rheological studies showed that the storage modulus values were smaller for the more acetylated samples and increased with the temperature and the polymer concentration. All the gels presented storage modulus superior to loss modulus, evidencing more elastic than viscous characteristics. The results obtained in this work suggest a gelation process based on a balance between O and N-acetylation and intermolecular bonds.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422008000300004chitosangelrheology |
| spellingShingle | Rosangela Balaban Garcia Dayse Luzia Pinheiro da Silva Marta Costa Fernanda Nervo Raffin Naira Machado da Silva Ruiz Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous medium Química Nova chitosan gel rheology |
| title | Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous medium |
| title_full | Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous medium |
| title_fullStr | Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous medium |
| title_full_unstemmed | Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous medium |
| title_short | Avaliação de géis obtidos a partir da acetilação da quitosana em meio heterogêneo Evaluation of gels obtained from acetylation of chitosan in heterogeneous medium |
| title_sort | avaliacao de geis obtidos a partir da acetilacao da quitosana em meio heterogeneo evaluation of gels obtained from acetylation of chitosan in heterogeneous medium |
| topic | chitosan gel rheology |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422008000300004 |
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