Intrusion volume

In this study, a mercury intrusion experiment was performed with a constant injection rate by regulating the intrusion pressure [58]. This is different from the conventional mercury intrusion experiment where the intrusion pressure is initially kept constant to record the mercury intrusion volume, then incremented to record the resultant incremental intrusion. In our experiment, the injection rate was kept extremely low so that the pressure loss due to flow was negligible compared with the capillary pressure. The data from this constant-rate mercury intrusion (CRMI) method, also called APEX [58], was collected through the pressure fluctuations as a function of intrusion volume, shown in Figure 3.7.4. 

The mercury level is monitored with a capacitance probe as shown in Fig. 20.1. The signal from the capacitance probe and from the pressure transducer are plotted on an X-Y recorder as intrusion volume and pore radius, respectively. 

It is easy to observe the important effect of UPF the pore size distributions tend to go to the right as UPF increases this means that, for the same accumulated intrusion volume, the mean pore diameter is smaller as UPF increases. 

Despite their marked difference in size (as confirmed by optical microscopy examination), no significant difference in the in vitro dissolution profiles corresponding to the three SDDP fractions could be found The bulk and the sieved fractions of SDDP yield similar specific surface area values as determined by adsorption of Krypton (BET method). This is further confirmed by MIP measurements for which the calculated specific surface areas and total intrusion volumes were found to be equivalent. As also shown by SEM, the corresponding MIP curves demonstrate the existence, whatever the sieved SDDP fraction studied, of open intraparticular pores with a mean access diameter (of about 0 6 tim) which is sufficiently large for water molecules to penetrate into them. Hence, one can understand the equivalence of dissolution rates obtained on the three granulometric fractions. 

An Autopore III from Micromeritics was used for the Mercury Intrusion Porosimetry analysis. The analyzed powders were outgassed at room temperature under vacuum until a residual pressure of 20pmHg was reached. Mercury was then introduced into the sample holder When the pressure is increased, mercury penetrates into the powder and the corresponding intrusion volume is recorded... 

The MIP results were calculated using the Washburn equation [3] (see below) assuming a cylindrical pore model graphs representing the intrusion volume versus pore diameter were plotted. 

Figure 1 Example of a t>pical cumulaih e intrusion volume of mercury versus pressure curv e...

The pore size distribution is derived, assuming a cylindrical pore model, from the intrusion volume-pressure curve using the Washburn law dp = -Ay cos0) / P, where y is the surface tension of mercury (484 mN/m), 6 the solid/mercury contact angle (130°) and P the pressure exerted by the mercury. 

Intrusion volume of all autoclave-cured composites was bigger than that of water-cured except PAO. It is noticeable that the pore diameters of autoclaved composites exceed in diameters of 1 micrometer and 0.01 micrometer while water-cured ones exceed in 0.1 micrometer. Among all cases, water-cured PA1 shows the minimum intrusion volume, which performed the maximum flexural strength. 

Mix proportion Cure Intrusion volume (cc/gr) Pore surface Area (m2/gr) Area ratio (AC150/W28) Average pore diameter (micrometer) Apparent density (gr/cc)... 

Fig. 4.5. Mercury porosimetry analysis of a commercial (SCT-US Filter) tubular aAhOa asymmetric membrane support (Micromeritics ASAP 2000). (a) Cumulative intrusion volume as a function of the applied pressure/pore diameter (b) differential intrusion volume as a function of the pore diameter.

Figure 4. Effect of CO2 pressure on on morphology of macroporous crosslinked polymer monolith, (a) BET surface area (continuous line = total surface area, hed line = micropore surface area) (b) Percent micropore volume (c) Median pore diameter (d) Intrusion volume (macropore volume).

Tetramethylguanidinium lactate ( TMGH][Lac]) (see Figure 21.3) was used by Wu and Zhu, et al. [5] in 2009 for SO2 removal. The IL was dispersed on silica particles via an incipient wetness technique and the resulting materials were carefully characterized. The intrusion volume, specific surface area, and porosity decreased with higher IL loading, while at the same time the apparent density and... 

TIV = Total Intrusion Volume (cmVg) MPD = Median Pore Diameter (nm)... 

Table 3 summarizes total intrusion volume as seem by mercury porosimetry between 200 and 55000 psi, for the Celite FC and some typical catalysts in their calcined form. 

Whatever the catalyst precursor, the intrusion volume is 40 to 50% that of the pure support indicating that mercury porosimetry also detects some texture modifications in the catalyst, as compared to the original carrier. However, if we take into account that 60% of the mass in the calcined catalyst is due to nickel, we reach the conclusion that the total pore volume of the carrier in the supported precursor is not different from that in the pure carrier. 

After drying at room temperature for 24 h, the clay membrane was sintered at 900 °C for 2h, after debonding at 250 °C for 1 h. Total porous volume and pore size distribution are measured by mercury porosimetry. This technique relies on the penetration of mercury into a membrane s pores under pressure. The intrusion volume is recorded as a function of the applied pressure and then the pore size was determined. The pore diameters measured were centered near 0.18 mm (Fig. 8). 

Material True density [g/cm ] Apparent density [g/cm ] Porosity H Maximum of pore radii [nm] Total intrusion volume [cmVg]... 

In mercury intrusion porosimetry, mercury surroimds the sample and application of differential pressure on mercury forces it into the pores. Mercury does not wet hydrophilic and hydrophobic pores and cannot enter these pores spontaneously owing to a small contact angle. Application of pressure on mercury can force it into the pores. The measured intrusion volume is equal to the pore volume and the differential intrusion pressure is related to pore diameter as given in Equation 8.43, where o and 0 are the surface tension and contact angle of mercury, respectively. Mercury porosimetry is valuable in determining the pore structure of the catalyst layer, especially for gas diffusion electrodes, where the distribution of gas and liquid phase pores is essential for the optimization of performance. 

Total Intrusion Volume (V) Total Pore Area (A)... 

Total Intrusion Volume and Cumulative Number versus Pore Diameter... 

The Pore Sizer 9310 gave self consistent intrusion volumes throughout the pore diameter range 3.0 to 0.01 /xm. The spread of the values of intrusion volume for the Autoscan 33 was wider than seen with the Pore Sizer 9310. 

Although the instruments gave different intrusion volumes the pore diameter modal valves for both chosen reference materials were similar. 

The CFP and Darcy air-permeability data discussed in Sect. 5.1 were correlated with mercury porosimetry (total PSD) and water porosimetry (hydrophobic PSD) before and after the consecutive aging/durability-testing experiments for cell M2. Mercury porosimetry can be effectively used to measure the total porosity and PSD of a GDL. This technique measures all porosity that exists (including constricted or dead-ended pores). The mercury intrusion volume also represents the hydrophobic plus hydrophilic surface domains because mercury is nonwetting for both types of pores. 

The mercury intrusion porosimetry method (Fig. 8.4) is a well-known technique that has been widely used to measure pore structure. Mercury is not wetted by nonwovens because the mercury—nonwoven interfacial free energy is greater than the gas—nonwoven interface. Mercury does not enter the pores spontaneously but can be forced into pores. Pressure required to intrude mercury into a pore is determined by the diameter of the pore. The measure of intrusion pressure and the intrusion volume yields the diameter and volume of passed and blinded pores. 

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