SWELLING PRESSURE OF POLY(VINYLMETHYLETHER) GEL (PVMEG) IN SWELLING PROCESS

The swelling pressure appearing in the swelling process of nonionic poly(vinylmethylether) gel (PVMEG) was studied experimentally. When a piece of PVMEG was placed in the space between two plates, it exerted a swelling pressure on the plates. Larger swelling pressure was observed under the conditions of lower temperature or smaller space between the plates, i.e., smaller gel porosity. The swelling pressure was primarily due to the contribution of the hydrogen bond of methoxyl groups in the polymer network with water molecules. The effect of salt on the swelling pressure of gel correlated well with the ratio of the valency to radius of the anion group in the salt.