2019, №1

сс. 14-31

Quas-Adiabatic Expansion of the Polylactide Foam: Features of the Porous Matrices Formation in the Region of Transition Between Sub- and Supercritical States of Plasticizing Carbon Dioxide

2019, №1

сс. 14-31

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D.A. Zimnyakov, V.N. Bagratashvili, S.A. Yuvchenko, I.O. Slavnetskov, A.V. Kalacheva, O.V. Ushakova

Key words: adiabatic expansion, foam, polylactide, carbon dioxide, equation of state, low-coherence reflectometry

Experimental data on the dynamics of quasi-adiabatic expansion of the foam, which is
formed on the base of carbon-dioxide-plasticized polylactide in the course of fast
depressurization, are presented. It is shown that, in the range of initial pressure, which
corresponds to the region of transition between the subcritical and supercritical states of
plasticizing agent, the substantial increase in the resulting volume of the formed porous
matrices takes place. Study of the structure of synthesized matrices at the mesoscopic level
provided using the low-coherence reflectometry showed the dramatic difference in
comparison with the synthesis conditions far from the transition region. The observed
features are interpreted in the framework of a qualitative model based on the equation of
foam state proposed by Ross. The considered model takes into account the sign of increment
of the internal energy of a plasticizing and foaming agent in the course of transition
between the initial and final thermodynamics states of the foamed polymer.

doi:10.1134/S1990793119070303