2021, №2

сс. 99-109

Supercritical Fluid Synthesis of High Porous Polylactide Matrices: Fundamental Features and Technological Aspects of Formation, Development and Stabilization of Polymer Foams

2021, №2

сс. 99-109

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D.A. Zimnyakov, M.V. Alonova, E.V. Ushakova, O.V. Ushakova, V.K. Popov, N.V. Minaev, S.A. Minaeva, E.O. Epifanov

Key words: amorphous polylactide, carbon dioxide, foaming, nucleation

The features of the formation, development and stabilization of the structure of foamed
amorphous D,L-polylactide during slow (quasi-isothermal) and fast (quasi-adiabatic)
pressure relief of supercritical carbon dioxide used as a plasticizing/foaming agent have
been investigated. The following regularities have been established: 1) the values of the
foam expansion factor during quasi-adiabatic depressurization are significantly lower
than in the quasi-isothermal regime due to significant dissi pation of the internal energy
of the «polymer—foaming agent» system due to internal friction in the system; 2) an
expansion-collapse effect is observed with quasi-isothermal foaming; 3) at an intermediate
stage between nucleation and intensive development of foam, the growth of pore nuclei
in the plasticized polymer has a self-similar character. The results obtained are significant
for the selection of foaming modes that provide the required structural characteristics of
the synthesized highly porous matrices intended for use in regenerative medicine and
tissue engineering.

doi:10.1134/S1990793121080182