Particle Growth and Development During the In-Situ Precipitation of Silica in a Polymeric Matrix

Abstract

ABSTRACTThe hydrolysis of tetraethoxysilane much used in the sol-gel approach to ceramics can be studied in a matrix isolation technique in which the silica thus formed precipitates within a polymeric material. This technique was applied here in the in-situ precipitation of silica particles in an elastomeric matrix of poly(dimethylsiloxane). Transmission electron microscopy and mechanical property measurements were carried out as a function of time over a period of 60 days. The equilibrium amount of silica precipitated was obtained relatively quickly, after approximately one day, but reorganization of the particles continued for several days thereafter. This “aging” process resulted in particles that are better defined and more uniform in size, but their ability to reinforce the elastomeric materials was only marginally increased. Scattering techniques are also being used to obtain additional information on this interesting process.