Dynamic Mechanical Losses in Filled Poly(Dimethylsiloxane) Networks

Abstract

Abstract This investigation focused on the study of dynamic mechanical losses in silica-filled networks of poly(dimethylsiloxane) (PDMS). Some of the samples were filled using a novel method, specifically the in situ precipitation of particulate silica either after or during network formation. Others were filled using the customary method of mechanically blending already-prepared silica into the elastomer prior to its crosslinking, and some were prepared without any filler at all. The resulting materials exhibited a variety of relaxation behaviors over the temperature range 120–260 K. The glass transition temperatures Tg showed only a slight dependence on the presence of the filler particles and crosslinks, but the filler was found to reduce both the degree and rate of crystallization for the in situ filled networks. The results obtained document how the techniques employed for incorporating particulate fillers change the viscoelastic properties of an elastomeric network, and how dynamic testing can yield a great deal of insight and useful information on the mechanical properties of polymers in general.