Portal de Periódicos da CAPES

Polymerization kinetics of octene‐1 catalyzed by metallocene methylaluminoxane investigated with attenuated total reflectance fourier transform infrared (ATR‐FT‐IR) spectroscopy

1992; Wiley; Volume: 30; Issue: 6 Linguagem: Inglês

10.1002/pola.1992.080300607

1099-0518

Brian W. S. Kolthammer, Debra Jean Mangold, D. R. Gifford,

biodegradable polymer synthesis and properties

Abstract The kinetic parameters have been measured for octene‐1 solution polymerization at 120°C catalyzed by zirconocene with the cocatalyst methylaluminoxane. The polymerizations were performed in an attenuated total reflectance (ATR) reaction cell. The progress of the reactions were followed by observing the disappearance of octene‐1 using the 910 cm −1 band measured by FT‐IR spectroscopy. The dependence of the reaction rate, R p , on catalyst concentration and cocatalyst/catalyst ratio was examined. The catalyst deactivation mechanism was studied by fitting the experimental data to mathematical models involving second‐order propagation and either first or second order catalyst deactivation. Second‐order catalyst deactivation provided a much better fit. The calculated deactivation rate constant, k d , is 21 ( M s) −1 . This model is used to determine the propagation rate constant for Al/Zr = 4 × 10 3 as k p = 19.9 ( M s) −1 . A decrease in Al/Zr = 3 × 10 2 lowered the propagation rate constant, k p , to 9.6 ( M s) −1 indicating that less than 50% of the initial Zr is active at this Al/Zr ratio.