The role of water on dehydrofluorination in PVDF/K2CO3 percolative composites

Effect of Carbonate Source on the Dehydrofluorination Process in Polyvinylidene Fluoride/Alkali Metal Carbonate Composites

“…Accordingly, upon thermal treatments, more water will be involved to increase the efficiency of dehydrofluorination reactions. Indeed, we have newly confirmed that water plays a critical role on PVDF dehydrofluorination during thermal treatment . Because of this higher efficiency of the dehydrofluorination process, PKC showed a marked increase in I D / I G with the content of K 2 CO 3 up to 30 wt %.…”

“…Indeed, we have newly confirmed that water plays a critical role on PVDF dehydrofluorination during thermal treatment. 7 Because of this higher efficiency of the dehydrofluorination process, PKC showed a marked increase in I D / I G with the content of K 2 CO 3 up to 30 wt %. However, further increasing the carbonate content above the percolation threshold may produce filler agglomerates, thus increasing the filler/filler interface population to the detriment of the matrix/filler interface fraction, 4 and result in an insufficient amount of HF, as well as a preferential reaction to form KF again.…”

“…In a recent paper, we have reported the presence of a complex reaction loop in percolative composites PVDF/K 2 CO 3 to gradually consume the raw materials . After mixing the constituent phases, i.e., alkali metal carbonate (M 2 CO 3 , M = Li, Na, and K) and PVDF, in the presence of moisture, the composite samples before thermal treatment consisted of physically mixed PVDF and a certain amount of MHCO 3 as well as hydrated water in sesquihydrate or sesquicarbonate double salt systems because of moisture absorption. ,,, Upon thermal treatment, decompositions of MHCO 3 and hydrated compound release water, and the generated water further reacts with M 2 CO 3 to yield hydroxide due to the basic nature of M 2 CO 3 (pH > 7): 2 MH CO 3 → normalM 2 CO 3 + normalH 2 normalO + CO 2 normalM 2 CO 3 · italicn normalH 2 normalO → normalM 2 CO 3 + italicn normalH 2 normalO → MOH + MH CO 3 → ... …”

“…In a previous paper, we have reported that percolative composites consisting of potassium carbonate dispersed in polyvinylidene fluoride (PVDF) polymeric matrix showed a rather high dielectric constant and electrical conductivity at the percolation threshold (30 wt % K 2 CO 3 ) due to the formation of chemically activated interfaces in the composite, as interfacial polarization resulted in high values of dielectric permittivity . Further studies revealed the presence of a complex reaction loop for the formation of activated carbon (AC) from PVDF dehydrofluorination during thermal treatment, as the net effect of these reactions is to generate a carbon-based nanocomposite in the polymer matrix. , The system has many marked merits: e.g., low-cost raw materials, extremely simple fabrication procedure, mesoporous surface structure, high flexibility, and light weight, which makes it promising for portable, flexible, and wearable energy storage applications.…”

“… 5 Further studies revealed the presence of a complex reaction loop for the formation of activated carbon (AC) from PVDF dehydrofluorination during thermal treatment, as the net effect of these reactions is to generate a carbon-based nanocomposite in the polymer matrix. 6 , 7 The system has many marked merits: e.g., low-cost raw materials, extremely simple fabrication procedure, mesoporous surface structure, high flexibility, and light weight, which makes it promising for portable, flexible, and wearable energy storage applications.…”