STRUCTURE-PROPERTY BEHAVIOUR OF NEW HYBRID MATERIALS

L. MUSANTE; J. SAMBETH; R. TORREGROSSA; P. VÁZQUEZ; J. M. MARTÍN-MARTÍNEZ

Zalakaros

Conferencia; Eurofillers 2007; 2007

Organic/inorganic hybrid materials prepared by the sol-gel approach have rapidly become a fascinating new field of research in materials science. The explosion of activity in this area in the past decade has made tremendous progress in both the fundamental understanding of the sol-gel process and the development and applications of new organic/inorganic hybrid materials. Basically, sol-gel reactions can be viewed as a two-step network-forming polymerization process. Most commonly, metal alkoxides are hydrolyzed to generate intermediate species of metal hydroxides. These species then undergo a stepwise polycondensation reaction to form a three-dimensional network. This network structure imposes restrictions on the molecular movement, thereby making it possible to obtain a multicomponent system without crystallization. Essentially all studies on such systems have concentrated on a mixture of inorganic components, and the final products are usually hard and brittle. In light of the success of making multicomponent sol-gel glasses, it appeared to the authors that new hybrid materials could be made through the incorporation of some organic-based species that have appropriate functional groups to undergo the co-condensation reaction with inorganic-based alkoxides. If this attempt was successful, it could provide a new way of bridging organic and inorganic materials. In addition, the material obtained should show some properties of the inorganic glassy matrix as well as possibly some characteristics of the incorporated components. Therefore, materials with new or special application might be made by choosing appropriate reacting components for this new sol-gel process. In this process, the acidity of the environment and the water content of the system have been proven to display a critical effect on the structure of the final product. The combination of organic and inorganic components and the synergism of their properties in one material is particularly useful and allows the development of materials with totally new properties.   The objective of this work is the comparison of the different degree from hydrofobicity of silica obtained by means of the sol-gel method, using two modifiers for such aim: tris-hydroximetyl-aminometane (TRIS) and 1,1,1,3,3,3–hexametyldisilane (HDMS), incorporated in separated form and its comporting with pure silica. The obtained materials were characterized by TEM-EDX, FT-IR, DRIFTS, DRX, DRS, SEM and pH measurements, extremely important for the future use of these fillers on the adhesives in water-based formulations.