Kinetics of non-catalytic process of polylactide formation during dispersion of lactic acid solution
E. N. FEDOSEEVA, V. B. FEDOSEEV
Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
Keywords: lactic acid, polylactide, polycondensation in spray, size effect
Abstract
The kinetics of lactic acid polycondensation in the dispersions of liquid-gas type is investigated. The dispersions were obtained by depositing drops of lactic acid spray or applying an ensemble of millimetre-sized drops from a capillary onto a glass substrate. The average droplet diameter for the fine and coarse-dispersed samples differed by more than an order of magnitude. The dynamics of changes in the amount of lactic acid in washouts from the substrate were analysed using anion chromatography. It has been confirmed that polylactide is formed during dispersion at room temperature and atmospheric pressure without the use of a catalyst. The reaction rate is directly related to the diameter of droplets in the dispersion. It has been shown that an increase in temperature from 20 to 40 °C causes an increase in lactic acid conversion by a factor of 1.5.
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