| Summary: | 碩士 === 淡江大學 === 化學工程學系 === 89 === Base catalysts enhanced ethanolysis and aminolysis reactions of room temperature vulcanized polydimethylsiloxane network were studied with the aid of a model compound. Tetrakis(trimethylsiloxy)-silane (M4Q) was chosen as a model compound the PDMS network. Experimental results showed that the rate of disappearance of M4Q decreased with increasing concentrations of base catalyst and ethanol. The reaction rate was increased by increasing the reaction temperature. Products of high molecular weight were also found as the reaction proceeded. Ethanolysis was the main reaction when ethanol and diethylamine coexisted in the reaction system.
The mechanism and rate law of the ethanolysis and aminolysis reactions were proposed. A quasilinearization method was employed to determine the best set of the kinetic parameters of ethanolysis. Initial rate analysis was used to determine the parameters of aminolysis. The reaction constants of ethanolysis reaction at temperatures of 5 ,30 ,40 and 50℃ are 0.0028 ,0.0053 ,0.0075 and 0.0097 min-1M-2, respectively. The reaction constants of aminolysis at temperature 5, 8, and10℃ are 0.0061, 0.0065 and 0.0068 min-1M-2, respectively. The activation energies of the ethanolysis and aminolysis reaction are 19.244 kJ/mole and 14.526 kJ/mole, respectively. The initial rate of aminolysis reaction was faster than that of ethanolysis reaction. However, aminolysis reached equilibrium much faster than ethanolysis.
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