Polyhydroxyurethane (PHU) has been studied as a potential replacement for polyurethane (PU), the latter of which is synthesized via reaction of alcohols with isocyanates. Because isocyanates are coming under increasing regulatory scrutiny, there is a need to investigate the synthesis and structure-property relationships of non-isocyanate-based polyurethane-like polymers. One such polymer is PHU which can be synthesized via cyclic carbonate aminolysis, resulting in polymers which contain urethane linkages with adjacent hydroxyl groups. In the case of segmented PUs in the form of multiblock linear copolymers, the urethane linkages are confined to the hard-segment domains which are dispersed in a soft-segment matrix, leading to thermoplastic elastomers. My research group has considered the role of the adjacent hydroxyl group in PHU in modifying the nanophase separation that can be achieved in segmented PHUs and that underlies the macroscopic properties of the polymer. Here, I will demonstrate how the presence of the hydroxyl group and resulting intersegmental hydrogen bonding with certain soft segments can lead to complete phase mixing and loss of nanophase separation. With other soft segments which moderate the intersegmental hydrogen bonding, the resulting PHUs exhibit nanophase separation but with broad interphases and thus exhibit behavior that makes them well designed as broad-temperature-range damping materials. Finally, with yet other soft segment which eliminate the intersegmental hydrogen bonding, the resulting PHUs are thermoplastic elastomers, the properties of which can be tuned via chain extender molecular structure to be competitive with polyurethane thermoplastic elastomers. Finally, I will comment on the potential to address the challenge associated with recyclability of network or cross-linked PHUs, thereby providing a sustainability advantage to PHUs that is not present with polyurethanes.

Novel segmented Polyhydroxyurethane (PHU): Control of nanophase separation to achieve properties unlike and like those of segmented polyurethane and the potential to overcome challenges associated with recyclability of network PHU

253rd National Meeting (2017)

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