PHYSICOCHEMICAL AND CATALYTIC INVESTIGATIONS OF GRAFTED POLY(TETRAFLUOROETHYLENE) COMPLEXED WITH SOME TRANSITION-METAL NITRATES

Radiation-induced graft polymerization of methacrylic acid into poly ( tetrafluoroethylene) by the mutual irradiation technique has been stud ied. The obtained hydrophilic solids were treated with solutions conta ining calculated amounts of iron, cobalt, nickel, or copper nitrates. The amounts of these transition metal nitrates were fixed at 16 wt%, e xpressed as metal oxide. IR, XRD, TG, and catalysis of CO oxidation re action by O2 have been carried out on the various prepared solids. The results obtained revealed that most of iron and copper species were c ontributed in complex formation of the polymeric material via carboxyl ic groups while some of the cobalt and nickel were involved in the com plex formation and the rest remained as separate phases. The thermal t reatment either in air at 400-degrees-C or in vacuo at 240-degrees-C l ed to degradation of the treated grafted polymeric material with subse quent formation of poly (methacrylic acid) together with Co3O4 (poorly crystalline phase) and NiO (having moderate crystallinity) and minute amounts of Fe2O3 and CuO (undetected by XRD). The PTFE-g-PMAAc treate d with the different transition metal nitrates and subjected to heatin g under vacuum at 240-degrees-C exhibited different catalytic activiti es that vary in the order: Co > Ni > Cu much greater than Fe. The cata lytic activity was mainly dependent on the produced amount of free oxi de and their degree of division. (C) 1993 John Wiley & Sons, Inc.