Thermal properties and TGA-FTIR studies of polyacrylic and polymethacrylic acid doped with metal clusters

Polyacrylic (PAA) and polymethacrylic acid (PMAA) doped with metal clusters were prepared by radical polymerization. The colloids were obtained by cocondensation of the metals and acrylic acid at 77 K using several metals such as Au. Ag, Pd, Cu, Bi, Sn, Sb, Ge, Ga, In, Cd and Zn. The presence of the metal clusters avoids the formation of larger molecular weight polymers. A complete study of the thermal degradation between 50 and 550 degrees C has been carried out, and the decomposition temperatures (TD) are obtained from the second derivative. In PAA, the highest TD corresponds to the undoped polymer, 546 degrees C, but in PMMA, the Pd doped polymer increases the T(D2) from 467 to 469 degrees C for the lowest molecular weight. In fact. the T(D) of the highest molecular weight polymer increases 27 degrees C the same as PAA-Ge. FTIR spectroscopy of the gases from TGA indicate that the product has been evolved during the experiment (60 min) with PAA, while the first gas evolved between 20 and 30 min and then from 37 to 45 min for PMMA shows that during the first decomposition mainly MAA is found. During the second decomposition besides the characteristic bands for MAA some alkenes are observed. (C) 2000 Elsevier Science Ltd. All rights reserved.