ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
The miscibility of blends of polymethyl methacrylate (PMMA) and polyvinylidene fluoride (PVF2) is investigated using triple resonance 1H–19F–13C cross polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR). Two techniques are introduced which give information on miscibility on the molecular level. By transferring magnetization from fluorines to protons, and subsequently from protons to carbons (19F–1H–13C double cross polarization), spectra are obtained in which all PMMA carbon resonances are present, proving the spatial proximity of PMMA and PVF2 chains. In the proton to fluorine cross depolarization experiment, with subsequent proton to carbon cross polarization, proton spin diffusion is studied to estimate the sizes of the domains in which PMMA and PVF2 are intimately mixed. Also the fraction of PMMA and PVF2 that is not intimately mixed can be extracted from these experiments. Four different compositions of the PMMA/PVF2 blend are investigated (with weight ratios 20/80, 40/60, 60/40, and 80/20). A model is proposed to explain the experimental results, and from which the domain sizes can be calculated. It is found that these domain sizes do not differ for different blend compositions. The PMMA/PVF2 ratios in these mixed domains are about the same, except for the PMMA/PVF2 80/20 blend, which is attributed to a dilution effect.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.461740
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