SYNTHESIS, CHARACTERIZATION, AND CHIROPTICAL PROPERTY OF OPTICALLY-ACTIVE POLY(UREA-URETHANE)S

Five new optically active poly (urea-urethane) s were synthesized by solution polyaddition of (1S,2S)-(+)-2-amino-3-methoxy-1-phenyl-1-propanol (4) with diisocyanates (diphenylmethane-4,4'-diisocyanate, toluene-2,4-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, m-xylylene diisocyanate) at 80-degrees-C for 60 h. In some cases, the reaction mixture transformed into a gel when cooled to room temperature. The reduced viscosities are between 0.14 and 0.63 dL/g depending on the solvents and diisocyanates. Thermal behaviors of these polymers were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The T(g) and crystallization temperature (T(c)) were in the range of 80-200-degrees-C and 220-238-degrees-C, respectively. Thermal decomposition started at about 275-degrees-C, and the residual weights at 400-degrees-C were 15-60% depending on the polymers. The conformation of the polymers in film state was studied by circular dichroism (CD) spectra, by comparison with the corresponding model compounds which were synthesized from 4 and phenyl isocyanate or propyl isocyanate. Polymers derived from aromatic diisocyanates formed as ordered conformation in the film state, while those from aliphatic diisocyanates did not. After packing as chiral stationary phases of high-performance liquid chromatography (HPLC), the polymers showed selective resolution to trans-stilbene oxide and trans-1,2-cyclopentanedicarboxanilide.