1987 Volume 44 Issue 12 Pages 857-865
Crosslinked polyurethane ionenes with different lengths of ionene segments were prepared by using poly (oxy-tetramethylene) glycol (Mn=984 and 2040) and 4, 4′-diphenylmethane diisocyanate as starting materials. The morphology and mechanical properties were studied. The equimolar reaction of the isocyanate-terminated prepolymer with 2-dimethylaminoethanol in DMF yielded a multifunctional amino-terminated prepolymer containing isocyanurate groups as branching points. Therefore, the crosslinked polyurethane ionenes were obtained by the reaction of the aminoterminated prepolymers with dihalides: p-xylylenedichloride (XDC) and 1, 6-dibromohexane (DBH). The ionene segment length was varied by adding N, N, N′, N′-tetramethylhexanediamine. With the increase of ionene segment length, the spherulites consisting of ionene were observed more distinctly in SEM micrographs. These polyurethane ionenes showed high 100% moduli (3.6-15.7MPa) and high tensile strengths (37.7-63.4MPa). DBH series of polyurethane ionenes showed diffraction peaks due to ionene segments in their X-ray diffraction curves, whereas XDC series of polyurethane ionenes showed amorphous halos. The differences in the results were explained by the formation of ionene segments with different lengths; that is, in DBH series the ionene segments with longer segment lengths were formed owing to its good solubility in DMF, while in XDC series the ionene segments with shorter lengths were formed.
