Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2005
Publication Date: 6/10/2004
Citation: Gallagher, S. 2004. Metal binding in siloxane-phosphonate polymers. Proceedings of Modern Trends in Organoelement and Polymer Chemistry. p.O22.
Technical Abstract: The polymerization of di- and trialkoxysilanes using conventional sol-gel techniques produces two and three-dimensional siloxane networks. The hydrolysis and condensation result in the formation of an alcohol under mild conditions which can be removed under reduced pressure and moderate temperature . Incorporation of phosphonate functionalized methoxysilanes, (CH3O)2CH3Si(CH2)3P=O(OCH3)2 or (CH3O)3Si(CH2)3P=O(OCH3)2, into the reaction mixture results in a polysiloxane bearing pendant phosphonate . Copolymerization of the silane-phosphonate monomers with di- and trimethoxysilane yields linear and crosslinked polysiloxanes. The linear copolymers, A, are viscous fluids stable to relatively high temperatures (270 oC). Phosphonate esters are known to coordinate metal salts via the phosphoryl oxygen. The siloxane-phosphonate copolymers in this work have been found to coordinate a variety of metal salts including, lithium, copper, nickel and uranium. They dissolve metal salts (up to 10% by weight) to form stable complexes. Crosslinked copolymers, B, form thermally stable glasses when using sol-gel techniques. Dissolution of the same metals in the monomer/catalyst solution prior to polymerization produced transparent-colored films and glasses coordinating up to 12% by weight of the salts.