Porous acrylonitrile polymer substrate for bonding ligands and

Abstract

A porous shaped substrate such as a porous bead is formed from polyacrylonitrile or a copolymer thereof containing nitrile groups. The substrate has a hydrophilic surface containing amide groups constituting about 1.8 mole percent to less than about 15 mole percent of the total nitrile groups, and containing no amide or carboxyl groups. The substrate is substantially non-swellable in water and is able to resist pressures in a columnar bed of up to about 3000 psi without collapsing. In forming the amide groups, polyacrylonitrile or copolymer thereof containing nitrile groups, an alkaline catalyst such as sodium hydroxide and a nonsolvent for the substrate such as methanol are combined to form a suspension. A peroxide is added to the suspension and the suspension is heated to hydrolyze nitrile groups to amide groups. Succinylated aminoethyl groups or activated carboxyl groups can be formed on the substrate and a bioactive ligand such as p-aminobenzamidine covalently bonded to the substrate. The bound ligand can then be used to complex a biologically active substance such as an enzyme to separate the substance from solution.