Lv. Adamova et al., THERMODYNAMICS OF INTERACTION BETWEEN WAT ER AND COPOLYMERS OF ACRYLATE AND ACRYLIC-ACID, Vysokomolekularnye soedinenia. Seria A, 35(7), 1993, pp. 20000893-20000897
The thermodynamics of swelling of acrylate-acrylic acid copolymers in
water has been studied for acrylates of different chemical nature. Kin
etic and equilibrium properties of water vapor sorption, as well as th
e values of factor of inaccessibility of copolymer polar groups for wa
ter molecules calculated by the method of group contributions, testify
that the polymer structure becomes more close during the sorption. Be
cause copolymers are hydrophobic, they absorb water in cluster form. F
or acrylic acid-methyl methacrylate and acrylic acid-methacrylate copo
lymers the thermodynamic stability of aqueous solutions rises with inc
reasing acrylic acid content, which is accompanied by the increase in
negative enthalpy DELTAh(M) values. For copolymers in a high-elasticit
y state DELTAS(m) > 0, while for glassy copolymers DELTAs(m) < 0. The
dependences of DELTAh(m) and DELTAs(m) on the alkyl radical size have
maximum, DELTAg(m) falls sharply with the increase in number of methyl
ene groups, while all thermodynamic parameters tend zero.