Abstract: In this paper, a series of α, ω-diaminopropyl terminated polydimethylsiioxane-polyurea and α, ω-diaminopropyl terminated polycyanopropyl methylsiloxane-polyurea were characterized by high resolution NMR.
The phase separation of these polymers was studied with breadline solid state NMR. The length of the hard segment and that of the soft segment have strong effect on the extent of phase separation.
The interactions between the soft segments and the hard segments (for example, hydrogen bonding) also affect the extent of phase separation.The hydrogen bonding in these polymers was studied by high resolution ¹H NMR. In concentrated solution the relative amounts of NH peaks have little dependence on concentration. The hydrogen bondings have significant effect on mechanical properties. The more the hydrogen bondings, the better the mechanical properties are.

Key words: Polysiloxane, Polyurea, NMR, Hydrogen bonding, Phase separation