Structural characteristics of porous polymers treated by freezing with water or acetone

The pore structure of nine polymers of different origin initial and treated in water and acetone for 24 h and then frozen by liquid nitrogen for 2 h was studied using low-temperature nitrogen adsorption. An average increase in pore volume and surface area is approximately 16 and 8%, respectively, after freezing with water and 19 and 8%, respectively, after treatment with acetone. However, for some samples, this effect is negative but for others, structural changes are significantly greater (up to 106%) than the average one. Certain treated polymers are characterized by shifted pore size distribution which is also accompanied by displacement of nitrogen adsorption energy distribution.