Solid-state NMR study on relationships between miscibility and chain mobility in poly(4-methyl styrene)/poly(cyclohexyl methacrylate) blend

The phase behavior and motional mobility in binary blends of poly(4-methyl styrene) (P4MS) and poly(cyclohexyl methacrylate) (PCHMA) have been examine d by C-13 solid state NMR techniques. The blend miscibility was studied by measuring the H-1 spin-relaxation times in the laboratory frame (T-1(H)) an d in the rotating frame (T-1 rho(H)), respectively. Although intermolecular spin diffusion contributes to the proton relaxations in accordance with ho mogeneity, T-1 rho(H) data shows signs of incomplete averaging. The T-1 rho (H) relaxation behavior indicates the existence of heterogeneous domains wi th shortest dimensions in the nanometer range, which is also supported by t he intermolecular cross polarization experiments with variable contact time s. In addition, according to the results of carbon T-1 rho relaxation time measurements, it is concluded that mixing is intimate somewhat enough to ca use a reduction in local chain mobility for P4MS and vice versa for PCHMA.