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Increasing solvent polarity and addition of salts promote β‐phase poly(vinylidene fluoride) formation
Author(s) -
Low Yuen Kei Adarina,
Tan Li Yi,
Tan Lay Poh,
Boey Freddy Yin Chiang,
Ng Kee Woei
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.38451
Subject(s) - solvent , differential scanning calorimetry , salt (chemistry) , phase (matter) , fluoride , materials science , polymer chemistry , scanning electron microscope , hexamethylphosphoramide , cationic polymerization , solvent effects , ionic bonding , fourier transform infrared spectroscopy , chemistry , chemical engineering , inorganic chemistry , organic chemistry , ion , composite material , physics , engineering , thermodynamics
This article investigates the effects of solvent polarity and salt addition on β‐phase poly(vinylidene fluoride) (PVDF) formation. Films were solvent cast in aprotic solvents of varying polarities with or without salt addition. Characterization was done by Fourier transformed infra‐red spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Decreasing fractions of β‐phase PVDF was observed with increasing drying temperature when less polar solvents were used. The most polar solvent (hexamethylphosphoramide) consistently produced films with at least 90.0% β‐phase PVDF within the crystalline regions. Melting temperatures increased in correlation to absolute proportions of β‐phase PVDF. Salt addition increased the formation of β‐phase PVDF by 30%, with salts of higher valencies and smaller ionic radii resulting in more significant increases. Taken collectively, using solvents of higher polarities and addition of salts with high cationic valencies and small ionic radii will maximize β‐phase formation in solvent cast PVDF films. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013