Pore volume of hypercrosslinked polymers

The total pore volume of porous materials may be determined 

The apparent density is also badly defined. It actually uses volumes of a polymer sample measured either by microscopy or by mercury pycnometry under 1 atm pressure. With pores large enough, these methods can provide different results. From this consideration it follows that the most reliable method of measuring the pore volume W, of a porous material, by comparing its apparent and true densities, bears serious uncertainty. 

According to Table 7.7 the estimated pore volume, IV, of hypercrosshnked polymers prepared from linear polystyrene is rather small. It increases with the degree of crosslinking, but does not exceed 0.5cm /g for rigid networks crosslinked with MCDE to 100%. For somewhat more flexible networks crossHnked with bis-chloromethylated diphenyl to the same extent, the value of the estimated pore volume is even smaller, 0.37cm /g. 

The method of mercury intrusion provides less exact, but stiU acceptable results for the pore volume values of were found to be sHghtly 

As opposed to the apparent specific surface area, pore volume of hypercrosslinked polymers is strongly dependent on the conditions of their synthesis. Tables 7.9 and 7.10 demonstrate that the pore volume noticeably increases with increasing dilution of the initial polystyrene solution, both in EDC and cyclohexane. 

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