The Effect of Aliphatic or Aromatic Substituents on the Synthesis and Properties of Polyurethanes From <scp>AB</scp> ‐Type Monomers

ABSTRACT AB‐type monomers enable a more flexible molecular design of polyurethane synthesis than the conventional methods by the polyaddition of diol and di‐isocyanate, that is, various side chain structures can be easily integrated on the former. Meanwhile, the impact of the substituent effect has not been clearly investigated on the synthesis and properties of polyurethanes from AB‐type monomers despite its fundamental importance. Herein, we developed four new AB‐type monomers exhibiting certain substituents to study the above issue. Interestingly, the introduction of a benzene ring to the side chain moiety did not significantly affect the thermal properties of the polyurethane compared with the corresponding polymer having an n ‐butyl substituent, while that to the main chain moiety drastically changed the reactivity of the monomer and the thermal properties of the resulting polymer. Moreover, a 2‐ethylhexyl side chain structure increased the solubility and flexibility of the polyurethane framework while maintaining the high monomer reactivity at the same time, indicating it would work as a useful comonomer to increase the processability of rigid polymers.