The phase behavior and motional mobility in binary blends of poly(4-methyl styrene) (P4MS) and poly(cyclohexyl methacrylate) (PCHMA) have been examined by 13C solid state NMR techniques. The blend miscibility was studied by measuring the 1H spin-relaxation times in the laboratory frame (T1H) and in the rotating frame (T1ρH), respectively. Although intermolecular spin diffusion contributes to the proton relaxations in accordance with homogeneity, T1ρH data shows signs of incomplete averaging. The T1ρH relaxation behavior indicates the existence of heterogeneous domains with shortest dimensions in the nanometer range, which is also supported by the intermolecular cross polarization experiments with variable contact times. In addition, according to the results of carbon T1ρ relaxation time measurements, it is concluded that mixing is intimate somewhat enough to cause a reduction in local chain mobility for P4MS and vice versa for PCHMA.
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