Miscibility and Molecular Motion of PMAA/PVAc Blends Investigated by High-Resolution Solid-State CPMAS 13 C NMR
2002; American Chemical Society; Volume: 35; Issue: 23 Linguagem: Inglês
10.1021/ma020867c
ISSN1520-5835
AutoresAtsushi Asano, Masaru Eguchi, Miho Shimizu, Takuzo Kurotsu,
Tópico(s)Material Dynamics and Properties
ResumoThe miscibility of poly(methacrylic acid) (PMAA) and poly(vinyl acetate) (PVAc) blends was investigated by the CPMAS 13C NMR. The 1H spin−lattice relaxation time in the laboratory frame ( ) showed that the PMAA/PVAc blends are homogeneous on a scale of 20−50 nm, and the 1H relaxation time in the rotating frame ( ) revealed that the PMAA/PVAc-rich blends are partially inhomogeneous on a scale of 2−5 nm, while the PMAA-rich/PVAc blends, including the PMAA/PVAc = 1/1 blend, are completely miscible on the scale. The domain size of the PMAA/PVAc = 1/1 blend was also estimated from the Goldman−Shen experiment. The obtained maximum domain size of 2.5 nm is consistent with the results of . The decomposition of 13C NMR spectra for the carboxyl (COOH) and carbonyl (COO) regions and the 13C spin−lattice relaxation time in the laboratory frame ( ) suggested the existence of an interpolymer interaction between PMAA and PVAc: the interaction is most likely a hydrogen bond and acts an important role for a great miscibility. The dependence of on the PMAA molar ratio indicates that the molecular motion of PVAc is largely affected by PMAA.
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