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

Five new optically active poly (urea-urethane) s were synthesized by s olution polyaddition of (1S,2S)-(+)-2-amino-3-methoxy-1-phenyl-1-propa nol (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, th e reaction mixture transformed into a gel when cooled to room temperat ure. 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 thermogra vimetric analysis (TGA). The T(g) and crystallization temperature (T(c )) were in the range of 80-200-degrees-C and 220-238-degrees-C, respec tively. Thermal decomposition started at about 275-degrees-C, and the residual weights at 400-degrees-C were 15-60% depending on the polymer s. The conformation of the polymers in film state was studied by circu lar dichroism (CD) spectra, by comparison with the corresponding model compounds which were synthesized from 4 and phenyl isocyanate or prop yl isocyanate. Polymers derived from aromatic diisocyanates formed as ordered conformation in the film state, while those from aliphatic dii socyanates did not. After packing as chiral stationary phases of high- performance liquid chromatography (HPLC), the polymers showed selectiv e resolution to trans-stilbene oxide and trans-1,2-cyclopentanedicarbo xanilide.