Modulus of three and four functional poly(dimethylsiloxane) networks

Networks formed from ci, w divinyl poly(dimethylsiloxane) end- linked with tn-and tetrafunctional hydrosilanes are used to test several theoretical relations for the small strain modulus. The results indicate that topological interactions between chains have a large influence on the modulus, however, the suppression of junction fluctuation by topological interactions seems to be small for PDMS networks. Independent measurement of the topological interactions between chains, the plateau modulus G on linear PDMS, agrees well with that determined from the networks. The influence of hydrosilane side reactions on determination of network structure parameters was accounted for.