Complex sentence: An ion-exchange resin or ion-exchange polymer is an insoluble matrix (or support structure) normally in the form of small (0.5--1 mm diameter) beads, usually white or yellowish, fabricated from an organic polymer substrate.
Split into simpler sentences: An ion-exchange resin or ion-exchange polymer is a resin or polymer that acts as a medium for ion exchange. It is an insoluble matrix (or support structure) normally in the form of small (0.5--1 mm diameter) microbeads, usually white or yellowish, fabricated from an organic polymer substrate.