The effects of the synthesis parameters on the xerogels structures and on the swelling parameters of the poly(methacrylic acid) hydrogels

Poly(methacrylic acid) hydrogels were synthesized. The effects of the synthesis parameters: the neutralization degree of methacrylic acid and the concentrations of monomer, crosslinker and initiator on the xerogels structural properties: the xerogel density (rho(xg)), the number average molar mass between the network crosslinks (M-c), the crosslink degree (rho(c)), the number of elastically effective chains totally induced in a perfect network per unit volume (V-e), the distance between the macromolecular chains (xi) and the equilibrium swelling degree (SDeq) and the swelling kinetics was investigated. As the concentrations of crosslinker, monomer and initiator increase, the value of rho(xg), rho(c) and V-e increases and decreases the value of M-c, xi and SDeq. With the increase in the neutralization degree of methacrylic acid, the values of rho(xg), M-c, xi, SDeq increase, while the rho(c) and V-e decrease. The xerogels structural properties, SDeq and swelling kinetic parameters are mainly in power law form functional relationships with the synthesis parameters as well as with the xerogels crosslinking degree. (C) 2009 Elsevier B. V. All rights reserved.