SYNTHESIS OF HYBRID HYDROPHOFIC SILICA AS FILLER IN POLYURETHANE ADHESIVE

L. MUSANTE; J. VEGA-BAUDRIT; P. VÁZQUEZ; J.M. MARTÍN-MARTÍNEZ

Miami

Conferencia; 29th Annual Meeting of the Adhesion Society; 2006

A sol-gel process in the presence of organic species able to chemically interact with the metal alkoxides can be used to produce hybrid organic-inorganic materials.   Hybrid material means a disordered physical-chemical system that forms intricate organic and inorganic networks. The degree of linking and cross-linking of the organic and inorganic networks influences the mechanical and chemical properties and can be controlled by varying, for example, the amount of organic precursor, the catalyst or time of stirring mixture. The relative simplicity and versatility of the sol?gel process, when compared to covalent-bonding methods to obtain hybrid materials, associated with low cost, are responsible for its extensive use. The novelty of this study was the preparation method of silica having a high number of surface silanol groups but very low number of adsorbed water molecules. Immobilization has been mainly directed to silica gel, because of its physical and chemical surface has been investigated and it offers many advantages over organic surfaces: i) A large variety of silylating agents can be used, allowing a myriad of pendant functional groups to be immobilized; ii) Functional groups immobilized on silica gel react more easily than those on an organic support because of a large number of crosslinking bonds which may require hours to reach equilibrium; and iii) Silica unreact with organic solvents and have high thermal resistance.