Influência da presença de quitosana e tensoativos em emulsões ternárias

• Ano de defesa: 2015
• Autor(a) principal: Regattieri, Adriana Barbosa
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Química; Centro de Ciências Exatas; UFES; Programa de Pós-Graduação em Química
• Palavras-chave em Português: Chitosan; Surfactants; Paraffinic compound; Surface tension; Quitosana; Tensoativos; Composto parafínico; Tensão superficial; Emulsões; Química; 54
• Link de acesso: http://repositorio.ufes.br/handle/10/4734

Emulsions are systems used in various types of industrial applications, including different areas of interest such as food technology, personal products, paints, pesticides, pharmaceuticals, etc. This work focusesin studying the behavior of the surface tension of surfactant systems in different solvents andthe study of emulsions defined ternary system Chitosan / surfactant / Hexane in theexperimental techniques of tensiometry, turbidity and flow time were critical to the preparation and characterization of the system. Other techniques have also been used for characterization of emulsions, such as emulsifying index, HLB number, optical microscopy images, and infrared spectra. It is to develop a methodology to prepare and analyze emulsions containing hexane, chitosan and surfactants which modify the load conditions through intermolecular interactions suchas dipole-dipole and other hydrophobic and van der Waals forces. It was found that no studies involving this ternary system, which led to the development of this research. In this study we investigated the effect of the solvents water and acetic acid solution 0.02 mol L-1in surfactant sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium bromide (CTAB) and Triton X-100, as well as their interactions with the biopolymer chitosan. The experimental technique of tensiometry was used to analyze the behaviorof the surface tension in those systems at ambient temperature. In the presence of acetic acid there was a significant decrease in the critical micelle concentration (CMC) in the case of anionic SDS, and a small increase of this value for the neutral Triton X-100. The behavior of the surface tension observed for the neutral surfactant Triton X-100 showed more uniform compared to the other two surfactants CTAB and SDS. Analyses of the chitosan / SDS / Hexane emulsions verified the emulsifying capacity of the surfactant SDS as evidenced by the interactions between the system components that contribute to obtaining more stable emulsions. Due to the volatility of hexane, air particles comprising the system, it was observed that the emulsion foam is present in the greatest amount of hexane. Material flow times (about 25 seconds) were observed in the emulsions in the concentrations of the three components were closest in concentration ranges, which may lead to further interact with the mixture. The highest value for the surface tension (39.62 mN/m) was measured for the emulsion in which the solution0.37% (w/v) of biopolymer chitosan was 85% (v / v) in the emulsion. The SDS-chitosan insoluble complex was established from the high turbidity values (>50NTU) obtained in emulsions with higher concentrations of SDS and chitosan. The surface tension values for the systems with different surfactants show the influence of surfactant in the emulsion as it approached the value of pure solutions of surfactants, resulting in deviations from the calculated values below of 4% inthe studied composition, 15% (v/v) Chitosan 70% (v/v) surfactant and 15% (v/v) hexane