Cre. Mansur et al., Thermal analysis and NMR studies of methyl methacrylate (MMA)-methacrylic acid copolymers synthesized by an unusual polymerization of MMA, J APPL POLY, 75(4), 2000, pp. 495-507
Methyl methacrylate-methacrylic acid (MMA-MAA) copolymers were prepared fro
m the polymerization reaction of the methyl methacrylate (MMA) monomer with
concentrated nitric acid (65% HNO3) at different reaction times in the abs
ence of other reagents in the reaction mixture. The hydrolysis degrees of t
he MMA-MAA (sodium salts) copolymers estimated by thermogravimetry (TG) cor
roborated the data obtained by chemical titration. By calorimetry (DSC), a
relationship between the glass transition temperature (T-g) and the hydroly
sis degree was obtained. The results presented a deviation from linear beha
vior and it was related to the strength of the interactions involved in the
copolymer chains. The equation that relates the glass transition temperatu
re to the interaction parameter, chi, for miscible binary polymer blends wa
s applied for the MMA-MAA copolymers and demonstrated the composition depen
dence of chi. The molecular mobility was determined by nuclear magnetic res
onance (NMR) in the solid state and through the proton spin-lattice relaxat
ion time in the rotating frame. The NMR data were in a good agreement with
the results obtained by calorimetry. (C) 2000 John Wiley & Sons, Inc.