Grafted islands-in-the-sea nonwoven for high capacity ion exchange bioseparation

A method for preparing a polymer-grafted and functionalized nonwoven membrane adapted for use in bioseparation processes, comprising:

• i) receiving a nonwoven web comprising a plurality of islands-in-the-sea fibers or a plurality of island fibers remaining after removal of the sea component of bicomponent islands-in-the-sea fibers;
• ii) optionally, removing the sea component of the bicomponent islands-in-the-sea fibers to expose the island fibers thereof;
• iii) grafting a methacrylate polymer onto a surface of the island fibers to form a plurality of polymer segments covalently attached thereto, thereby forming grafted island fibers, the grafting step comprising contacting the nonwoven web with a solution comprising an initiator and at least one methacrylate monomer and exposing the nonwoven web to ultraviolet light having a wavelength of 365 nm and intensities between 1 and 30 mW/cm2 to initiate polymerization of the at least one methacrylate monomer, wherein the nonwoven web is not subjected to a separate UV pretreatment;
• and
• iv) optionally, functionalizing the grafted island fibers to attach at least one functional group adapted for binding to a target molecule to each of the plurality of polymer segments of the grafted island fibers.