SILICA-POLYVIOLOGEN HYBRIDS PREPARED BY THE SOL-GEL ROUTE .1. SYNTHESIS AND THERMAL CHARACTERIZATION OF IONENE SYSTEMS

Three ionene viologen polymers were synthesised by the Menshutkin reac tion and characterised by chemical and spectroscopic methods. These we re incorporated into silica hybrids using the sol-gel method. The tran sparency of the majority of the products suggested phase separation ha d not occurred. An attempt to control cracking during drying using a d rying control agent appeared to be only partially successful. Polyviol ogen contents up to as high as 40% by weight could be achieved by a mo dification of the method involving evaporating a saturated solution of the polymer before incorporating in the sol-gel system. The thermal c haracteristics of the polymers and the hydrids have been studied using thermogravimetric analysis (TGA) and differential scanning calorimetr y (DSC). TGA of the hybrids showed a three-stage decomposition process dui: to residual solvent/condensation volatiles and polymer decomposi tion. DSC showed evidence for liquid crystallinity and high temperatur e crystallisation in the polymers, but both these effects were masked in the hybrids.