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Previous issue date: 2017-07-28 / Biofilmes e revestimentos comest?veis s?o camadas finas de materiais biodegrad?veis aplicados sobre produtos alimentares que desempenham um papel importante na sua preserva??o, distribui??o e comercializa??o. A f?cula de mandioca ? um dos melhores candidatos ? prepara??o de revestimentos comest?veis, por ser um pol?mero completamente biodegrad?vel no solo e na ?gua e de f?cil obten??o. No entanto, a f?cula possui limita??es em suas propriedades f?sico-qu?micas quando comparada aos pol?meros sint?ticos. Por sua vez, o melhoramento destas propriedades foi proposto neste estudo a partir da adi??o de 5%, em massa, de argila em rela??o ? massa seca de biopol?mero. A compatibiliza??o superficial da argila com a matriz biopolim?rica foi realizada por modifica??o superficial na presen?a de tr?s tipos de tensoativos (brometo de cetiltrimetil am?nio, dodecil sulfato de s?dio e ?lcool laur?lico etoxilado). O efeito de tr?s modifica??es sequenciais e cumulativas na argila foi caracterizado por Difra??o de Raios X (DRX), Transformada de Fourier por Radia??o Infravermelha (FTIR), Microscopia Eletr?nica de Varredura (MEV), Espectroscopia de Energia Dispersiva de Raios X (EDS), ?ngulo de Contato (AC), Potencial Zeta (ZETA) e An?lise Termogravim?trica (TGA). A argila modificada sinergicamente na presenta dos tr?s tensoativos evidenciou o maior distanciamento basal entre as camadas de silicato, cerca de 10 nm a mais em rela??o ? argila natural. Os filmes de f?cula de mandioca com argila natural e modificada foram caracterizados como bionanocomp?sito intercalado ou esfoliado atrav?s das an?lises de Microscopia de For?a At?mica (AFM), Microscopia ?ptica (MO), DRX, FTIR, MEV e AC. A influ?ncia da argila modificada e da natural na mudan?a das propriedades f?sico-qu?micas dos filmes de f?cula original foi investigada quanto ? permeabilidade ao vapor d??gua, ductibilidade, opacidade, estabilidade t?rmica e solubilidade em ?gua. Por fim, a argila modificada sinergicamente na presenta dos tr?s tensoativos foi o material de refor?o que mais contribuiu para o melhoramento das propriedades f?sico-qu?micas do filme de f?cula controle, dentre as quais reduziu 90,6% da permeabilidade ao vapor d??gua, bem como 77,43% da dissolu??o m?xima. / Biofilms and edible coatings are thin layers of biodegradable materials applied to food products that play an important role in their preservation, distribution and commercialization. Cassava starch is one of the best candidates for the preparation of edible coatings, because it is a completely biodegradable polymer in soil and water and easy to obtain. However, the starch has limitations in its physical-chemical properties when compared to the synthetic polymers. In turn, the improvement of these properties was proposed in this research from the addition of 5%, by mass, of clay in relation to the dry mass of biopolymer. The surface compatibilization of the clay with the biopolymer matrix was performed by surface modification in the presence of three types of surfactants (cetyltrimethyl ammonium bromide, sodium dodecyl sulfate and ethoxylated lauryl alcohol). The effect of three sequential modifications on the clay was characterized by X-ray Diffraction (XRD), Fourier Transform by Infrared Radiation (FTIR), Scanning Electron Microscopy (SEM), Dispersive Lightning Spectroscopy (DLS), Contact Angle (AC), Zeta Potential (ZETA) and Thermogravimetric Analysis (TGA). The clay modified synergistically in the presence of the three surfactants showed the greatest basal space between the silicate layers, about 10 nm more than the natural clay. The cassava starch films with natural and modified clay were characterized as bionanocomposite intercalated or exfoliated through Atomic Force Microscopy (AFM), Optical Microscopy (MO), XRD, FTIR, SEM and AC analyzes. The influence of modified and natural clay on the change in the physical-chemical properties of the original starch films was investigated for water vapor permeability, ductility, opacity, thermal stability and water solubility. Finally, the synergistically modified clay in the presence of the three surfactants was the reinforcing material that contributed the most to the physical-chemical properties of the control starch film, among which it reduced the permeability to water vapor by 90.6%, as well as 77.43% of the maximum dissolution.
Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/24018 |
Date | 28 July 2017 |
Creators | Monteiro, Mayra Kerolly Sales |
Contributors | 59545844434, Nascimento, Andr? Ezequiel Gomes do, 01018188401, Santos, Francisco Klebson Gomes dos, 00779263405, Nunes, Shirlle Katia da Silva, 02757549448, Barros Neto, Eduardo Lins de |
Publisher | PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA QU?MICA, UFRN, Brasil |
Source Sets | IBICT Brazilian ETDs |
Language | Portuguese |
Detected Language | English |
Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
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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