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Solid state 19 F NMR study of crystal transformation in PVDF and its nanocomposites
Author(s) -
Pallathadka Pramoda K.,
Tay S.S.,
Tianxi Liu,
Sprenger Peter
Publication year - 2006
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20631
Subject(s) - materials science , nanocomposite , magic angle spinning , nmr spectra database , crystallization , solid state nuclear magnetic resonance , crystal structure , fluoride , analytical chemistry (journal) , spectral line , crystallography , nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , composite material , chemistry , organic chemistry , inorganic chemistry , physics , astronomy
The polymorphism of poly(vinylidene fluoride) (PVDF) and its nanocomposites was studied by means of solid state nuclear magnetic resonance spectroscopy. 13 C cross polarization magic angle spinning ( 13 C CP MAS) NMR spectra were recorded using simultaneous high‐power decoupling on both the proton and fluorine channels. Both 1 H → 13 C and 19 F → 13 C CP experiments were conducted, giving identical results apart from intensity variations due to the CP efficiency. Two main resonances for the CF 2 and the CH 2 groups were observed for both neat PVDF (PVDF‐C0) and the nanocomposite containing 2 wt% clay (PVDF‐C2) samples. 19 F CP MAS spectra were obtained from long proton spin‐lock experiments with a shorter contact time. The results showed two strong resonances at −84 and −98 ppm with equal intensities, representing the α‐form crystalline structure of PVDF. It was shown that the clay induces the crystallization of PVDF in β‐form. Our earlier investigations using thermal analysis and X‐ray scattering methods also showed crystal transformation of PVDF in its clay nanocomposites. POLYM. ENG. SCI. 46:1684–1690, 2006. © 2006 Society of Plastics Engineers