Isothermal Crystallization Behavior of Poly(vinylidene fluoride) Based Membrane with Graphene Oxide

2020 ◽  
Vol 35 (4) ◽  
pp. 398-407
Author(s):  
X.-T. Qiao ◽  
L. Gong ◽  
S.-H. Chen ◽  
S.-P. Zhan ◽  
X.-D. Sun
Keyword(s):  
Graphene Oxide ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Vinylidene Fluoride ◽  
Poly Vinylidene Fluoride

scholarly journals Non-Isothermal Crystallization Behavior of Poly(vinylidene fluoride) in Dialkyl Phthalate Diluents during Thermally Induced Phase Separation Process

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 782
Author(s):  
Yakai Lin ◽  
Yuanhui Tang ◽  
Lin Wang ◽  
Xiaolin Wang
Keyword(s):  
Chain Length ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Vinylidene Fluoride ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Poly Vinylidene Fluoride ◽  
Dialkyl Phthalate

The non-isothermal crystallization behavior of poly(vinylidene fluoride) (PVDF) in dialkyl phthalate diluents during the thermally induced phase separation (TIPS) process was investigated by differential scanning calorimetry (DSC) at various cooling rates. Dialkyl phthalates with different alkyl chain-length, namely dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP), were used as the diluent. The effects of alkyl chain-length of dialkyl phthalate and cooling rate on the non-isothermal crystallization behavior as implied by the Avrami analysis modified by Jeziorny and Mo’s analysis were determined. The values of half-time, t1/2, and the parameters Zc and F(t), which characterized the kinetics of non-isothermal crystallization, showed that the crystallization rate increased with the increase of the alkyl chain-length of dialkyl phthalate due to the lower compatibility between PVDF and dialkyl phthalate. Moreover, the alkyl chain-length of dialkyl phthalate also has a great impact on the compact spherulitic structure of PVDF membranes prepared from different PVDF/dialkyl phthalate blends. With the decrease of the alkyl chain-length of dialkyl phthalate, the number of spherulites increased and the size of spherulites became smaller. This research thus not only proves the effects of alkyl chain-length of dialkyl phthalate on the non-isothermal crystallization behavior of PVDF, but also provides a systematic strategy to evaluate a single diluent during the TIPS process.

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