Síntese e caracterização de micropartículas de etilcelulose e seu uso na encapsulação do fungicida tebuconazole
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2014-09-30
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Universidade Estadual Paulista (Unesp)
Resumo
Este trabalho teve como objetivo sintetizar micropartículas de etilcelulose e avaliar a encapsulação do fungicida tebuconazole. Foi empregado um planejamento fatorial para estudar as variáveis que controlam a morfologia. As variáveis avaliadas foram concentração do polímero etilcelulose, a velocidade e tempo de homogeneização de alta velocidade e a concentração do surfactante utilizado. Foi avaliada ainda a influência do tebuconazole sobre as características das micropartículas, sendo o diâmetro, rendimento e a distribuição utilizada como parâmetros para avaliação da síntese. As micropartículas de etilcelulose foram obtidas pelo método de inversão de fase à temperatura constante e a caracterização foi realizada por FEG-SEM, espectroscopia FT-IR, Espectroscopia Raman e análise térmica (TG, DTG e DTA). A análise do tebuconazole foi realizada por CG-EM. Foram obtidas micropartículas de etilcelulose com diâmetro médio variando de 0,21 ?m (±0,08) a 0,55 ?m (±0,22) para o experimento PE-14. Os parâmetros que mais influenciaram os efeitos sobre o diâmetro das micropartículas foram a concentração do polímero (+0,28) e velocidade de homogeneização (-0,43). O rendimento das micropartículas variou entre 10,07 e 96,59%. Os resultados de DRX indicaram que a distribuição do TBZ nas partículas de EC foi a nível molecular, ou seja, não houve a formação de cristais no interior das microesferas. A presença de TBZ nas partículas foi adequadamente quantificada por cromatografia a gás e também foi identificada pela presença do pico Raman em 1597,98 cm-1. O deslocamento deste pico foi atribuído às interações intermoleculares do TBZ com a matriz. A eficiência de encapsulação do tebuconazole nas partículas de etilcelulose foi de 76,0 (±4,9) para EEC25, 69,6 (±4,0) para EEC50, 60,6 (±2,3) EEC100 e 45,5 (±1,1) EEC200. Os dados obtidos pela análise térmica indicam...
This study aimed to synthesize microparticles of ethylcellulose and evaluate the encapsulation of the fungicide tebuconazole. A factorial design was used in order to study the variables that control the microparticles morphology. The evaluated variables were concentration of ethylcellulose polymer, speed and time of high pressure homogenization and concentration of surfactant. The influence of tebuconazole on the characteristics of microparticles was also evaluated and the diameter, yield and the distribution were used as synthesis parameters. The ethylcellulose microparticles were obtained by phase inversion method at constant temperature and the characterization was performed by FEG-SEM, FT-IR s and Raman spectroscopy, thermal analysis (TG, DTG and DTA). Ethylcellulose microparticles were obtained with an average diameter ranging from 0.21 ?m (±0.08) to 0.55 ?m (±0.22) for the PE-14 experiment. The parameters that influence the effects on the diameter of the microparticles were the concentration of the polymer (+0.28) and mixing speed (-0.43). The yield of the microparticles ranged between 10.07 and 96.59%. XRD results clearly indicated that the distribution of the particles of TBZ was at molecular level and there was no formation of crystals within the microspheres. The presence of the TBZ into the particles was measured by gas chromatography and it was also identified by Raman peak at 1597.98 cm-1 and this peak was attributed to the intermolecular interactions of the matrix with TBZ. The encapsulation efficiency of TBZ was 76.0 (±4.9) to EEC25 69.6 (±4.0) to EEC50, 60, 6 (± 2.3) EEC100 and 45.5 (±1.1) EEC200. The data obtained by thermal analysis show that the particles of ethylcellulose are thermally stable up to 160 ° C temperature.
This study aimed to synthesize microparticles of ethylcellulose and evaluate the encapsulation of the fungicide tebuconazole. A factorial design was used in order to study the variables that control the microparticles morphology. The evaluated variables were concentration of ethylcellulose polymer, speed and time of high pressure homogenization and concentration of surfactant. The influence of tebuconazole on the characteristics of microparticles was also evaluated and the diameter, yield and the distribution were used as synthesis parameters. The ethylcellulose microparticles were obtained by phase inversion method at constant temperature and the characterization was performed by FEG-SEM, FT-IR s and Raman spectroscopy, thermal analysis (TG, DTG and DTA). Ethylcellulose microparticles were obtained with an average diameter ranging from 0.21 ?m (±0.08) to 0.55 ?m (±0.22) for the PE-14 experiment. The parameters that influence the effects on the diameter of the microparticles were the concentration of the polymer (+0.28) and mixing speed (-0.43). The yield of the microparticles ranged between 10.07 and 96.59%. XRD results clearly indicated that the distribution of the particles of TBZ was at molecular level and there was no formation of crystals within the microspheres. The presence of the TBZ into the particles was measured by gas chromatography and it was also identified by Raman peak at 1597.98 cm-1 and this peak was attributed to the intermolecular interactions of the matrix with TBZ. The encapsulation efficiency of TBZ was 76.0 (±4.9) to EEC25 69.6 (±4.0) to EEC50, 60, 6 (± 2.3) EEC100 and 45.5 (±1.1) EEC200. The data obtained by thermal analysis show that the particles of ethylcellulose are thermally stable up to 160 ° C temperature.
Descrição
Palavras-chave
Polimeros, Pesticidas - Formulação, Analise termica, Espectroscopia Raman, Cromatografia a gás, Gas chromatography
Como citar
MARTINS, Eucarlos de Lima. Síntese e caracterização de micropartículas de etilcelulose e seu uso na encapsulação do fungicida tebuconazole. 2014. 117 f. Tese (doutorado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Química de Araraquara, 2014.