Pore Size Distribution (PSD) Measurements of Silica Gels by Means of Differential Scanning Calorimetry

Ishikiriyama, Kazuhiko; Todoki, Minoru; Motomura, Kinsi

doi:10.1006/jcis.1995.1154

Cited by 189 publications

(148 citation statements)

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“…The density and the value of DH (enthalpy change of fusion) of frozen pore water, both of which depend on temperature, can be calculated from the dependences [10,12]:…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

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Application of differential scanning calorimetry to study porous structure of hydrothermally modified silicas

Charmas

Skubiszewska–Zięba

2017

J Therm Anal Calorim

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The paper presents the studies on determination of physicochemical and structural properties of hydrothermally treated (HTT) silica gel Si-60, using the differential scanning calorimetry (DSC) and N 2 adsorption methods. Modification was performed in overheated water vapours or under the liquid water layer using various sources of thermal energy (in the classical autoclave or in the high-pressure microwave reactor). The characteristics of porous structure were determined on the basis of low-temperature nitrogen adsorption/desorption isotherms and using the calorimetric data (DSC) of thermal effects of phase transition of water introduced inside pores of the studied materials. Great compatibility of the characteristics obtained by means of the above-mentioned methods was proved. As follows from the SEM analysis, during HTT silica is rebuilt resulting in great changes of surface morphology and porous structure of the materials. The range of these changes depends on both the applied system (water vapour/liquid water) and the kind of used energy (classical/microwave).

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“…The density and the value of DH (enthalpy change of fusion) of frozen pore water, both of which depend on temperature, can be calculated from the dependences [10,12]:…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

“…This type of interactions is studied, among others, by differential scanning calorimetry (DSC) providing essential information about porous structure of the studied materials [10][11][12][13][14][15][16][17][18][19][20][21]. The method consists in studying phase solid/liquid transitions of the media contained in pores [15].…”

Section: Introductionmentioning

confidence: 99%

Application of differential scanning calorimetry to study porous structure of hydrothermally modified silicas

Charmas

Skubiszewska–Zięba

2017

J Therm Anal Calorim

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“…We decided to use both NLDFT and BJH method because even NLDFT is recommended for cylindrical pore analysis, the results of pore diameter value Table 2 Amount of non-freezing water per gram of silica D1, D2 and D6 at different moisture contents (t), expressed as thickness of nonfreezing liquid layer (t*) and as the amount of monolayers (w) The thickness of non-freezing liquid layer t* was calculated based on the values of the surface area obtained from NLDFT method. The amount of monolayers present in the silica channels was obtained under assumption that the van der Waals radius of water is equal to 0.3 nm [41] (b) (Table 1). It is well seen in the case of D7 for which pore diameter derived from NLDFT is higher than that obtained from XRD patterns.…”

Section: Resultsmentioning

confidence: 99%

Water thermoporosimetry as a tool of characterization of the textural parameters of mesoporous materials

Majda

Zimowska

Tarach

et al. 2016

J Therm Anal Calorim

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Water thermoporosimetry (TPM) is a powerful method for studying the properties of porous materials, devoted especially for investigation of the samples that can be destroyed in drying process. However, this method is not very popular and relatively rarely used because of problems with proper measurement procedure and choosing correct equation for the result interpretation. This report focused on refinement of general experimental protocols for water TPM. For the first time, the role of various parameters on the TPM outcomes was deeply investigated and simple and fast experimental mode was proposed. Additionally, based on the series of mesoporous silica SBA-15, the calibration procedure was employed and the reliable calibration equations were established.

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“…The method of thermoporosimetry has come into some use as a means of characterizing heterogeneous systems and crosslinked polymer heterogeneity. [7][8][9][10][11][12][13] In this method, thermal analysis is used to obtain melting point distributions and, through the Gibbs-Thomson (GT) equation, 14 relate crystal size and size distribution to the shape of the melting thermograms. In the case of crosslinked rubber, the melting point depression has an additional thermodynamic contribution different from size that is related to the polymersolvent interactions and should be described by the Flory-Huggins (FH) expression 15,16 for melting of the diluent in a polymer solution.…”

Section: Background and Introductionmentioning

confidence: 99%

Melting of solvents nanoconfined by polymers and networks

Qin

McKenna

2006

J Polym Sci B Polym Phys

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Thermoporosimetry is becoming increasingly used to study nanoscale heterogeneity and structure in polymer networks. The starting point for thermoporosimetry is the Gibbs-Thomson (GT) relation between melting point and inverse crystal size. In the case of polymers, the Flory-Huggins (FH) model also predicts that there is a depression of the melting point because of the mixing of the polymer and the solvent molecules, and this needs to be taken into account. The first step in analysis of size heterogeneity using thermoporosimetry and the GT equation requires that there be quantitative agreement between the FH theory and the melting points of the diluent in the uncrosslinked rubber. We find that both benzene and hexadecane exhibit excessive melting point depressions in uncrosslinked polyisoprene. This may imply that the uncrosslinked polymer is divided into 'nanoheterogeneities'. We further find that the heat of fusion decreases as polymer concentration increases for the benzene, but not for the hexadecane. Finally, we compare pore size distributions obtained for a crosslinked polyisoprene as determined from the melting behavior of n-hexadecane as a diluent, using different references for how the uncrosslinked polymer behaves. While number average distribution is not very different between the different analyses, the weight average distribution is.

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Pore Size Distribution (PSD) Measurements of Silica Gels by Means of Differential Scanning Calorimetry

Cited by 189 publications

References 0 publications

Application of differential scanning calorimetry to study porous structure of hydrothermally modified silicas

Application of differential scanning calorimetry to study porous structure of hydrothermally modified silicas

Water thermoporosimetry as a tool of characterization of the textural parameters of mesoporous materials

Melting of solvents nanoconfined by polymers and networks

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