Preparation, characterization and properties of gradient polymer blends: discussion of poly(vinyl chloride)/poly(methyl methacrylate) blend films containing a wide compositional gradient phase

We prepared several types of thick ≈200 μm films of a poly(vinyl chloride)/poly‐(methyl methacrylate) (PVC/PMMA) gradient polymer blend, which contained a widely waried compositional gradient phase, using a dissolution and diffusion method. We discussed the preparation conditions by classifying those gradient blend films into 5 types based on the results of differential scanning calorimetry (DSC) measurements and found the optimum conditions for preparing the ideal gradient blend consisting of only one extremely wide compositional gradient phase. Further, the gradient structures, which were evaluated by the results of DSC measurements, were confirmed by means of Fourier transform infrared/attenuated total reflection (FTIR‐ATR). Finally, the ideal blend was found to have significantly new or improved properties (e.g. a large half‐width of temperature of the dissipation factor tan δ) which cannot be observed in any PVC, PMMA homogeneously (that is ordinarily) miscible blend or a laminate system.