Abstract: A polymer composition containing components A and B provides a crosslinked network to form an elastomeric film. Component A comprises A1 a high molecular weight polymer containing units having carboxyl and/or hyroxyl groups, and A2 a relatively low molecular weight coreactant polyelectrolyte containing units having carboxyl and/or hydroxyl groups. Component B comprises a polyfunctional crosslinking agent capable of crosslinking with carboxyl and/or hydroxyl groups at ambient temperatures or higher. Crosslinker B may polymerize into higher molecular weight polymers, form covalent cross links between polymer A1 and polyelectrolyte A2, and/or entrap or entangle polymers A1, A2, and B. The crosslinking reaction may be enhanced by using an acid or acid-forming catalyst.