EXTENSIVE STRETCH OF POLYSILOXANE NETWORK CHAINS WITH RANDOM-COILED AND SUPER-COILED CONFORMATIONS

The stress-elongation (lambda) relations at large deformations for the polymer network chains with randomcoiled and supercoiled conformation s are investigated using the polysiloxane networks with high elongatio ns at break far over 10. Supercoil is the conformation of network chai ns in deswollen polymer networks which are made by removing solvent fr om the networks crosslinked in solutions at low polymer concentrations . The validity of the scaling concept of Pincus blob for the mechanica l response of a polymer chain is experimentally confirmed for the netw ork composed of randomcoiled chains. The analysis of the stress-lambda relations for the deswollen networks comprised of supercoiled chains on the basis of the Pincus blob concept suggests that supercoil is a m uch more contracted conformation relative to randomcoil.