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vol.38 número9CARACTERIZAÇÃO E AVALIAÇÃO IN VITRO DE NANOCOMPÓSITOS DE POLI (L-ÁCIDO LÁTICO) E NANOTUBOS DE CARBONO DE PAREDES MÚLTIPLAS PURIFICADOSSYNTHESIS AND BIOLOGICAL EVALUATION OF SPIRO[INDOLINE-3,4’-PYRANO[2,3-C:6,5-C’]DIPYRAZOL]- 2-ONES IN THE PRESENCE OF SBA-Pr-SO3H AS A NANOCATALYST índice de autoresíndice de assuntospesquisa de artigos
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Química Nova

versão impressa ISSN 0100-4042versão On-line ISSN 1678-7064

Resumo

TAIARIOL, Thalita S.; KAWACHI, Elizabete Y.  e  PARDINI, Luiz C.. INFLUÊNCIA DO CATALISADOR EM SOLUÇÕES POLIMÉRICAS PARA O PREPARO DE GÉIS ORGÂNICOS DE RESORCINOL-FORMALDEÍDO. Quím. Nova [online]. 2015, vol.38, n.9, pp.1162-1166. ISSN 1678-7064.  http://dx.doi.org/10.5935/0100-4042.20150124.

Resorcinol-formaldehyde (RF) organic gels have been extensively used to produce carbon aerogels. The organic gel synthesis parameters greatly affect the structure of the resulting aerogel. In this study, the influence of the catalyst quantity on the polymeric solution sol-gel process was investigated. Sodium carbonate was used as a basic catalyst. RF gels were synthesized with a resorcinol to formaldehyde molar ratio of 0.5, a resorcinol to catalyst (R/C) molar ratio equal to 50 or 300, and a resorcinol to solvent ratio of 0.1 g mL-1. The sol-gel process was evaluated in situ by Fourier transform infrared spectroscopy using a universal attenuated total reflectance sensor and measurements of the kinematic viscosity. The techniques showed the evolution of the sol-gel process, and the results showed that the lower catalyst quantity induced a higher gel point, with a lower viscosity at the gel point. Differential scanning calorimetry was used to investigate the thermal behavior of the RF dried gel, and results showed that the exothermic event related to the curing process was shifted to higher temperatures for solutions containing higher R/C ratios.

Palavras-chave : resorcinol; formaldehyde; kinematic viscosity; in situ FT-IR evaluation; DSC.

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