Ionic bonding in butadiene copolymers. I. Network formation

The mechanical effects of association between pendant ionic groups are investigated in series of butadiene–lithium methacrylate copolymers, butadiene–methyl (2-methyl-5-vinyl)-pyridinium iodide copolymers, and mixtures of these polyelectrolytes. Thermal and mechanical tests reveal a new transition above T_g in the pyridinium copolymers, designated T_t^*. Below this temperature the materials behave like covalently crosslinked elastomers. The complex between the metal carboxylates appears thermally dissociable at all temperatures. The mixing of the oppositely charged polyelectrolytes leads to the formation of more stable intermolecular pyridinium carboxylate links.