Synthesis and Properties of Hydrophilic Gels Prepared by Crosslinkage of Poly(vinyl alcohol)

Abstract

Hydrophilic gels were prepared by the crosslinkage of poly(vinyl alcohol) in suspension state with epichlorohydrin. The permeabilities were determined by eluting water soluble materials, such as poly(ethylene glycol) and dextran, through a column packed with the gels. Excluded molecular weight increased with the decrease of poly(vinyl alcohol) concentration in the aqueous solution and reached to 2X106. A new preparation method of bead-shaped poly(vinyl alcohol) has been developed. The beads of pely(vinyl acetate) were hydrolysed stepweise. Atthe first step, the beads were hydrolysed mainlyi on the surface in aqueous solution of sodium sulfate and sodium hydroxide followed by the addition of a small quantity of methanol, and at the second step, mainly on the inside in the alkaline methanol. The molecular weight and saponification degree of resulted poly(vinyl alcohol) were 67000 and 98.8mol%, respectively. Another type of hydrophilic gel was prepared by the crosslinkage of bead-shaped poly(vinyl alcohol), Tolylenediisocyanate, hexamethylene diisocyanate and epichlorohydrin were used as crosslinkage reagent. These gels could be available for the separation of materials containing various molecular weights. Gel, prepared by the crosslinkage of poly(vinyl alcohol) in the suspension state, was suitable for the separation of polymer, the others for the separation of oligomers. The slope of the calibration curve, α, was affected by the preparation method of the gel.