Melt viscosity ionomers, preparation

Polyoxymethylene Ionomers. Ionic copolymers have been prepared from trioxane and epichlorohydrin, followed by reaction with disodium thioglycolate (76). The ionic forces in these materials dismpt crystalline order and increase melt viscosity (see Acetalresins). 

Siegfried and co-workers (66,67) investigated thermoplastic IPNs based on SEES triblock copolymers with a polystyrene ionomer. Two subclasses of thermoplastic IPNs were identified those prepared by a sequential polymerization method, and those prepared by mechanically blending separately synthesized polymers. In each case, a polystyrene acid sulfate was neutralized dynamically in the melt with a concentrated solution of sodium hydroxide. The water steamed off rapidly under the reaction conditions. The first subclass resulted in lower melt viscosities, but more nearly equal dual-phase continuity was achieved with the second subclass. The subject of thermoplastic IPNs was recently reviewed by Sperling (68). 

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