Sponge Effects at the Interaction of Polymers with Low-molecular Compounds

Abstract

A competition among additives for a place in the polymer matrix under levelling effect of the blending enthalpy was found. The competition apparently contradicts the entropy nature of the mixtures exhibiting accelerated desorption of the added compound from films in a glassy-or jelly-like state. The effects considered cannot be treated by statistical of thermodynamics of solutions and the theory of "the chaos elements in the close order range". They are however, explainable by taking into account the specificity of the chainsponge structure function. The processes of the equilibrium sorption of vaporized compounds by polymers are explained by the mechanism of structural entropic solvation and described by the equation of the micropore volume filling theory.

The Entropic Mechanism of Water Solvation of Polymers

“…(1) with coefficients E = 640 J/ mol and n = 0.4, which differ just a little from the same coefficients (700 and 0.45, respectively) of the isotherm of n-hexane absorption by cellulose triacetate (CTA) films [8]. Thus, both cases display similar pseudo-Langmuir parts.…”

“…mechanism of low-molecular weight compounds (LMC) absorption by polymers were recently developed. Of special interest is the concept of the entropy factor of a non-combinatorial origin of dispersion forces [8]. The ordering of chain links reduces the chain entropy, but this reduction is overcome by an increase of the entropy of "tails" of the same chains organized as a fringe layer.…”

“…The fact that sorptional equilibrium of polymers with LMC is regulated by dispersion electromagnetic forces, which localize an admixture in the bulk of narrow micropores, gives an opportunity [8] to reconcile the well-known theory of vacancy solutions [13,14] and theory of bulk filling of micropores (TBFM) [lo].…”

“…According to the above model [8], absorption potential of the chain sponge can be presented as a function of the volume of absorbed molecules,…”

Heterophase mechanisms of thermal oxidation of polymers. New horizons

“…in the real heterogeneity of the `amorphous' polymer phase. 15,16,28,29 The molecular-chain sponge is actually a system of connected pendula (oscillators), the oscillations of which can become cooperated; this makes the units of macromolecules move apart to form nanopores with different widths.…”