Microphase structure of interpenetrating polymeric networks based on polyurethane and polyurethane ionomer

Interpenetrating polymer networks based on polyurethane and polyurethane ionomer were studied using wide‐angle and small‐angle X‐ray diffraction. The polyurethane network is a multiblock polymer based on the trimethylolpropane adduct with 2,4‐toluene‐diisocyanate and poly(propylene oxide tetrahydrofuran) copolymer. Polyurethane ionomer represents a network formed from poly(propylene glycol) containing three OH side groups, 2,4‐toluene‐diisocyanate, 2,2′‐dimethylethanol‐amine, and 1,5‐dibromopentene. The network polymers are characterized by structure heterogeneity developed during microphase separation as a result of hard and soft block segregation. The interpenetrating networks investigated are amorphous systems over the whole range of compositions. They form a very complicated structure where the phase separation of polyurethane and ionomer takes place. It is important to note that phase separation leads to the appearance of microphase structure periodicity due to regular arrangements of microregions enriched by one of the components. The latter fact is considered to be a sign of spinodal phase separation at the initial stages.