Premium
Thermal behaviour and annealing of poly(vinylidene fluoride)
Author(s) -
AlRaheil Ismail A.,
Qudah Ali M.
Publication year - 1996
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199611)41:3<323::aid-pi617>3.0.co;2-a
Subject(s) - annealing (glass) , crystallinity , materials science , differential scanning calorimetry , endothermic process , melting point , fluoride , composite material , polymer chemistry , thermodynamics , chemistry , organic chemistry , inorganic chemistry , physics , adsorption
In this study, we report the melting behavior of poly(vinylidene fluoride) (PVF 2 ) annealed in a differential scanning calorimeter. PVF 2 annealed under isothermal conditions often shows double or triple melting endotherms depending on the annealing temperature ( T a ) and the heating rate. The lower melting peak temperature increases as T a increases. When the annealing time is varied, there is a systematic increase in the size of the lower endotherms. This suggests that a portion of the main endothermic response is due to reorganization during the scan. Annealing PVF 2 not only increases the degree of crystallinity, but also improves the crystal perfection. The ability of an annealing sample to reorganize decreases as the annealing time increases. However, an additional third melting peak appears when PVF 2 is annealed at 140°C for a sufficiently long time. The existence of this peak suggests that more than one kind of distribution of crystal perfection may occur when PVF 2 is quenched from the melt into liquid nitrogen and subsequently annealed.