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  • Author: K. K. Unger x
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Abstract

A mixture characterized by the molar ratios of H2O/SiO2 = 20, SiO2/Al2O3, = 120, Na2O/SiO2 = 0.3 and 1.6 diaminohexane (DAH) as template was reacted at 182 °C. Dependent on the reaction time, the ratio of OH- /SiO2 and DAH/SiO2 ZSM-5 was crystallised with α-quartz as by-product. The materials were characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, thermogravimetry and differential thermal gravimetry.

Silica gel as a filler of separation columns fractionates and separates dissolved polystyrenes. Fractionation means: Continuous distribution of the polymeric homologues among the successive fractions of the eluate. Separation means: Discontinuous distribution. In both cases the polymeric homologues with higher molecular weights are transported more rapidly through the columns than the polymeric homologues with lower molecular weigths. Fractionation and separation of polystyrenes are based on characteristics of the space system within the silica gel particles. With equal dimensions of the columns fractionation and separation grow with the pore size of the silica gel particles.