Nmr and vibrational spectroscopic study of the order and mobility in polycarbonate and polycarbonate poly(ethylene oxide) blends

Time dependence of the gel formation in toluene solutions of polycarbonate (PC) was investigated by two-dimensional Fourier-transform infrared (2D FT- IR) correlation spectroscopy. The 2D correlation approach reveals chat ther e are at least three bands in the C=O stretching region. The intensity incr ease of the band at 1771 cm(-1) occurs later compared with the onset of the intensity changes of the bands at 1778 and 1765 cm(-1) corresponding To am orphous and crystalline-like domains, respectively. The band at 1771 cm(-1) is assigned to the chain conformations occurring in the partial-order regi ons accompanying crystalline-like domains. Splitting of the signals of arom atic carbons in the solid-state C-13 CP/MAS NMR spectra of semicrystalline PC and PC-PEG blends indicates restricted mobility resulting from the fixed ordering due to partial crystallinity of PC itself and from blending of PC with PEG. The decreasing mobility of PC with the increasing content of hig hly mobile PEO in the blends was proved by the dipolar dephasing rates obta ined in the H-1-H-1 CRAMPS (combined rotation and multi-pulse spectroscopy) NMR experiments.