Molecular structure of polymeric materials and sorption of water vapor

Effect of Chitin Nanofibrils on Biocompatibility and Bioactivity of the Chitosan-Based Composite Film Matrix Intended for Tissue Engineering

“…The thermal expansion coefficient α characterizes the main temperature contribution to the sorption value; its sign and value are determined by the interaction energy of water molecules and the elementary unit of the polymer. It can be calculated according to Equation [16] α=1.1×10−3−1.12×10−5sans-serif∆E*(±9.4%), where sans-serif∆E*=sans-serif∑sans-serif∆Ei/Mi is the specific energy of cohesion (351.7 J/g for chitosan, 385.9 J/g for chitin).…”

Osmotic phenomena in polymer sorption systems

“…The energy of polymer-sorbate interaction is propor tional to the heat of sorption and can be expressed using Eq. (12) through its parameters [16]: (20) where q i is the integral heat of sorption, is the thermal coefficient of sorp…”

“…This is evidenced by the bimodal sorp tion theory [8], indicating a state change of the poly mer and sorbate along the sorption isotherm, by NMR data on the state of the polymer and sorbate [8,12,13], by change of the polymer state from glassy to elas tomeric and thick flowing, and by other factors. A theoretic probabilistic model of sorption equation allows one to estimate the value of g; this equation sat isfactorily describes the isotherms of vapor sorption by glassy polymers and elastomers [14][15][16]: (12) where а, а 0 is the value of sorption at the chemical potential of sorbate in the gas phase and , respectively; p/p 0 is the equilibrium pressure of sorbate and the saturated vapor pressure; Е is the characteristic energy of adsorption; n = 0.3-0.33 for densely packed and soluble polymers in the sorbate; n = 0.5 for elastomers; and n = 0.7 for glassy polymers [14].…”

Activity coefficients of the low-molecular-mass components in swelling polymers

“…(4), (5)) can be expressed in terms of the absorption isotherm equation. In [19][20][21], the high descriptive ability of the equation of the theoretical probabilistic model of sorption was given:…”

“…, (19) , (20) where V 1 0 (T 1 ,O) is the molar volume of the LMMS extrapolated to zero pressure. Denoting the molar vol ume of the pure LMMS at a pressure of 0.5 (P'' + P') in terms of , equating μ and μ , and using the equality x 1 = θ, we obtain .…”