MECHANICAL-PROPERTIES OF ELASTOMERS WITH A STRONG PHYSICAL NETWORK INMETASTABLE STATES THAT ARISE DURING THE MOLDING OF THE MATERIAL

Rather stable nonequilibrium states typical of glassy polymers were fo und to exist in elastomers. A rubbery poly(nonyl acrylate-co-acrylamid e) was synthesized, which was characterized by high cross-linking dens ity provided by the amide-amide intermolecular interactions (strong ph ysical networks). The stress-strain properties in tension were shown t o be controlled by the history (molding temperature) of such copolymer s and remained unchanged for an infinitely long period of time (for mo re than one year). Annealing al temperatures below 50 degrees C was fo und to be inefficient, whereas annealing at temperatures above 150 deg rees C was shown to bring the elastomers from the metastable to the eq uilibrium state.