Géis superabsorventes de propionato acetato de celulose e acetato de celulose: síntese, caracterização e liberação controlada de pesticida
Hydrogels derived from cellulose acetate propionate (CAP) and cellulose acetate (CA) were synthesized with the cross-linking agents PMDA (Pyromellitic Dianhydride) and BTDA (Dianhydride 3, 3 ', 4, 4' Benzophenone Tetracarboxylated) with 3:1 stoichiometry in relation to the mass of the cros...
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| Format: | master thesis |
| Status: | Published version |
| Publication Date: | 2011 |
| Country: | Brasil |
| Institution: | Universidade Federal de São Carlos (UFSCAR) |
| Repository: | Repositório Institucional da UFSCAR |
| Language: | Portuguese |
| OAI Identifier: | oai:repositorio.ufscar.br:20.500.14289/1166 |
| Online Access: | https://repositorio.ufscar.br/handle/20.500.14289/1166 |
| Access Level: | Open access |
| Keyword: | hidrogéis propionato acetato de celulose pesticida cellulose acetate propionate cellulose acetate synthesis characterization controlled release pesticide paraquat ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA |
| Summary: | Hydrogels derived from cellulose acetate propionate (CAP) and cellulose acetate (CA) were synthesized with the cross-linking agents PMDA (Pyromellitic Dianhydride) and BTDA (Dianhydride 3, 3 ', 4, 4' Benzophenone Tetracarboxylated) with 3:1 stoichiometry in relation to the mass of the crosslinker agent x mass of available hydroxyls in the polymer chain. The gels were obtained in the form of films and particles, the raw materials were characterized with Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Spectroscopy in Region of Fourier Transform Infrared (FTIR) and in relation to the degree of substitution (GS). The gels synthesized were characterized using FTIR techniques in order to show the esterification, TGA and DSC to perform comparative analysis and study of thermal properties between the CAP and CA reagents and gels, and Scanning Electron Microscopy (SEM) were used for observation of the gels synthesized and the geometry of the particles obtained, the porosity of observation and observation of surface changes, was performed to determine the crosslinking density of the second theory of Flory Rehner, study the density of the gels, and degree of swelling of the study best solvent for swelling of the gels. Gels derived from CAP were tested in the adsorption studies and controlled release of the herbicide paraquat. For the phenomenon of controlled release, we studied the phenomena of transport and release curves. The release profiles were studied by using the mathematical model published by Korsmeyer-Peppas and the mainly results has showed that model was appropriated for process data analysis of controlled release in long periods. |
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