Estudo do processo e dos produtos da polimerização de biodiesel de óleo de soja com anidrido ftálico e 2-metil-imidazol utilizando biodiesel como solvente

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2011

RESUMO

This work present the polymerization study of the epoxidized methyl esters (MEE) obtained from soybean oil, with phthalic anhydride (AF) and 2-methyl-imidazole (2MI) using soybean oil biodiesel (BD) as solvent, as well as the products characterization. The gelation region for the system MEE/AF/2MI without BD was determined using the Flory¿s theory and it occurs for MEE molar fraction (XMEE) between 0.33 to 0.54. The evaluation of the polymerization enthalpy (¿H) indicates that the experimental stoichiometric composition of the system MEE/AF/2MI without solvent is near to XMEE=XAF=0.5. ¿H values higher than 76 J/g were observed for samples located in the theoretical gelation region. After, the stoichiometric composition was fixed and different polymers were produced varying only the amount of BD as a solvent. Kinetics and thermodynamics parameters of the polymerization using solvent were evaluated by DSC technique. The results show that BD acts as solvent in the polymerization reaction and a compensation effect between activation energy and pre-exponential factor logarithm was observed. The physical aspects and solubility experiments demonstrated the validity of the predictions by Flory¿s theory. The swelling tests suggest that the crosslink degree is an intrinsic property of the system and it is practically unaffected by the solvent. The thermal behavior was investigated using DSC and TGA techniques. The system presents two thermal transitions in the range between -13 to 20°C. The samples demonstrated two degradations; the first is related to the BD in the network, which was eliminated by the thermal treatment. The compensation effect was observed in the thermal degradation kinetics. Stress-strain curves evaluated by plane strain compression show that the polymers behave as ductile materials. The morphology of the samples was investigated by scanning electron microscopy and indicates that the increase in %BD increases the roughness and the presence of voids in the polymeric matrix.

ASSUNTO(S)

biodiesel oleo de soja polímeros transesterificação

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