Development of polymeric blends has become very important for polymer industries because they have been shown to be successful and versatile alternatives to obtain new polymers. In this work binary blends formed by poly(vinylpyrrolidone) (PVP) and poly(ethylene oxide) (PEO) were studied by solution and solid-state NMR to determine their physical interaction, homogeneity, and compatibility for use as membranes to separate water/alcohol. The NMR results allowed us to acquire information on the microstructure and molecular dynamic behavior of polymer blends. From the NMR solution it was possible to evaluate the microstructure: PVP presented a preferential syndiotactic distribution sequence and PEO presented two regions, one crystalline and the other amorphous. Considering the solid-state NMR results it was possible to evaluate the molecular dynamics and all binary blends, showing that PEO behaves as a plasticizer; some intermolecular interaction was also observed. An important point was to evaluate the microstructure of the carbonyl PVP using cross polarization/magicangle spinning (CP/MAS) and CP/MAS/dipolar decoupling that was not observed before.

ABSTRACT:It is well known that nuclear magnetic resonance spectroscopy (NMR) is a powerful method to characterize blends compatibility at the molecular level. In this work binary blends formed by poly(methylmethacrylate)/ poly(ethylene oxide), PMMA/PEO, were investigated by different solution and solid state NMR techniques to obtain information on blends homogeneity and compatibility. It was characterized that the values of T 1 H obtained by variable contact time and delayed contact time experiments, for each composition, were distinct and this fact suggests that regions with different molecular mobilities exist, as a consequence of blending interaction.

ABSTRACT:The ternary blends of poly(methyl methacrylate)/poly(vinyl pyrrolidone)/poly(ethylene oxide), PMMA/PVP/PEO, were prepared by melting process, using a Haake plastograph, and nuclear magnetic resonance spectroscopy (NMR) was used as a methodology to characterize the molecular mobility of blend components, because NMR has several techniques that allow us to evaluate polymeric materials in different time scales. The NMR results showed that the blends were miscible on a molecular level. The values of proton lattice relaxation time in the rotating frame (T 1 H) indicate that the ternary blend interaction did not reduce the intermolecular distance, because it is dipole-dipole. The molecular motion of each component, even in the miscible amorphous phase and the addition of PEO, has a definitive effect on the PMMA molecular mobility.

ABSTRACT:The development of polymer blends has become very important for the polymer industry because these blends have shown to be a successful and versatile alternative way to obtain a new polymer. In this study, binary blends formed by poly(methyl methacrylate) (PMMA) and poly(vinyl pyrrolidone) were prepared by solution casting and evaluated by solution and solid-state NMR. Variations in the microstructure of PMMA were analyzed by 13 C solution NMR. Solid-state NMR promotes responses on physical interaction, homogeneity, and compatibility to use these blends to understand the behavior of the ternary blends. The NMR results led-us to acquire information on the polymer blend microstructure and molecular dynamic behavior. From the NMR solution, it was possible to evaluate the microstructure of both polymer blend components; they were atactic. From the solid state, good compatibility between both polymer components was characterized.