Determination of thermal parameters of PVDF using a photoacoustic technique

Bonno, B.; Laporte, J. L.; d'León, R. Tascón

doi:10.1088/0957-0233/12/6/303

Cited by 19 publications

(9 citation statements)

References 16 publications

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“…Figure 3), we solved eq 4 with ΔH pol =-474.2 kJ/mol (at T=25 °C) 2 and k = 0.13 W/mK. 34,35 The calculated temperature difference between the center and the surface of the aggregates is plotted in Figure 4 versus the aggregate size, r. For small particles the temperature profile is flat (no temperature gradient), and the reaction in the polymer phase occurs under isothermal conditions (dispersions). But when aggregates exceed a size of a few millimiters (as in the case of precipitations in which bulky polymer is formed), the large amount of heat produced by the reaction causes a remarkable temperature increase in the particle core.…”

Section: Homopolymerization Reactionsmentioning

confidence: 99%

Copolymerization of VDF and HFP in Supercritical Carbon Dioxide: Experimental Analysis of the Reaction Loci

et al. 2010

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Free radical copolymerization reactions of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) were carried out in supercritical carbon dioxide at T = 50 °C. When ammonium carboxylate perfluoropolyether surfactants were used, the formation of polymer particles was observed provided that HFP mole fraction in the feed was not larger than 0.30. Under these conditions, the effect of the total interphase area of the polymer phase, A p, on the product properties was investigated by comparing experiments with largely different amounts of stabilizer, i.e., ranging from precipitation (smaller A p) to dispersion (larger A p) polymerization systems. We found that the copolymer molecular weight distribution (MWD) is heavily affected by A p. This experimental evidence strongly supports the presence of two reaction sites, the CO2-rich and the polymer-rich phase: the contribution of both is important in the examined range of operating conditions.

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Section: Homopolymerization Reactionsmentioning

confidence: 99%

Copolymerization of VDF and HFP in Supercritical Carbon Dioxide: Experimental Analysis of the Reaction Loci

et al. 2010

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“…% is the thermal conductivity of non-functionalized MWNT or P3-SWNT or AP-SWNT/PVDF composite. The theoretical thermal conductivity value of a pure PVDF polymer is 0.2 W·m −1 ·K −1 [ 40 , 41 ] and the presence of nanotubes in the PVDF matrix, irrespective of the nanotube structure, enhances the thermal conductivity of the polymer composites. However, the structure of the nanotube influences the degree of thermal conductivity enhancement.…”

Section: Resultsmentioning

confidence: 99%

A Comparative Study on the Role of Polyvinylpyrrolidone Molecular Weight on the Functionalization of Various Carbon Nanotubes and Their Composites

2021

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Polyvinylidene fluoride (PVDF) nanocomposites filled with polyvinylpyrrolidone (PVP) wrapped carbon nanotubes were prepared via a solution casting technique. The effect of the molecular weight (polymer chain length) of the PVP on the ability to wrap different nanotube structures and its impact towards nanotube dispersibility in the polymer matrix was explored. The study was conducted with PVP of four different molecular weights and nanotubes of three different structures. The composites that exhibit an effective nanotube dispersion lead to a nanotube network that facilitates improved thermal, electrical, and mechanical properties. It was observed that nanotubes of different structures exhibit stable dispersions in the polymer matrix though PVP functionalization of different molecular weights, but the key is achieving an effective nanotube dispersion at low PVP concentrations. This is observed in MWNT and AP-SWNT based composites with PVP of low molecular weight, leading to a thermal conductivity enhancement of 147% and 53%, respectively, while for P3-SWNT based composites, PVP of high molecular weight yields an enhancement of 25% in thermal conductivity compared to the non-functionalized CNT-PVDF composite.

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“…The commonly used polymer polyvinylidenefluoride (PVDF), which has a thermal conductivity of about 0.2 W m −1 K −1 , was chosen for the binder phase. [ 78–80 ] The CB shows a significantly higher bulk thermal conductivity of 24 W m −1 K −1 . [ 81–83 ] The effective thermal conductivity of the BCB composite is calculated according to the adapted model of Hamilton and Crosser, [ 84 ] which we presented in detail in our previous publication.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the Effective Thermal Conductivity of Cell Stacks of Li‐Ion Batteries

et al. 2020

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Knowledge of the thermal transport properties of the individual battery components and their combination is required for the design of thermally optimized lithium‐ion batteries. Based on this, the limiting components can be identified and potentially improved. In this contribution, the microstructures of commercial porous electrode coatings, electrode stacks, and cell stacks are reconstructed based on experimentally determined structure parameters using a specifically developed structure generation routine. The effective thermal conductivity of the generated stacked structures is then determined by a numerical tool developed in‐house based on the finite‐volume method. The results are compared with an analytical model for fast accurate predictions which takes the morphological parameter sets and the geometry of the stacks into account. Both models are used to identify the system‐limiting components via selected simulation studies. Finally, the results of both models are compared with experimental data for commercial electrode stacks and common literature values for cell stacks.

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Determination of thermal parameters of PVDF using a photoacoustic technique

Cited by 19 publications

References 16 publications

Copolymerization of VDF and HFP in Supercritical Carbon Dioxide: Experimental Analysis of the Reaction Loci

Copolymerization of VDF and HFP in Supercritical Carbon Dioxide: Experimental Analysis of the Reaction Loci

A Comparative Study on the Role of Polyvinylpyrrolidone Molecular Weight on the Functionalization of Various Carbon Nanotubes and Their Composites

Investigation of the Effective Thermal Conductivity of Cell Stacks of Li‐Ion Batteries

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