Selection Guide for Polymeric Resins

We carry a vast array of resins, from leading manufacturers; such as, DuPont Water Solutions, Mitsubishi, and Lanxess. Our product line includes adsorbent, ion-exchange (anion / cation), mixed bed, chelating, nuclear grade, hydrophobic interaction (HIC) and gel filtration/size exclusion products. These resins are appropriate for research-scale separations, as well as, purification and isolation applications. To better fit unique application requirements, we also provide custom packaging services of in-stock resins.

Selecting Ion-Exchange Resins

A resin that contains both an anion and a cation as bound ions is said to be ampholytic. Some ion exchange resins are prepared with chelating properties making them highly selective towards certain ions. In addition to their use in ion exchange, organic polymer supports, many of which are based on PS-DVB resins, are being used as polymeric catalysts in the expanding research area involving heterogenization of homogenous catalysts and as polymeric supports and reagents in combinatorial chemistry.

The internal structure of the resin beads, i.e., whether microporous (gel-type) or macroporous, is important in the selection of an ion exchanger. Macroporous resins, with their high effective surface area, facilitate the ion exchange process. These resins allow access to the exchange sites for larger ions, can be used with almost any solvent irrespective of whether it is a good solvent for the uncrosslinked polymer, and take up the solvent with little or no change in volume. Macroporous resins make more rigid beads, facilitating ease of removal from the reaction system. Microporous resins, since they have no discrete pores, solute ions diffusely through the particle to interact with exchange sites. Despite diffusional limitations on reaction rates, these resins offer certain advantages: These resins are less fragile, requiring less care in handling; react faster in functionalization and applications reactions; and possess higher loading capacities.

In addition to being a function of bead morphology, the kinetics of the exchange depends on the particle size distribution of the resin. Kinetics are enhanced by a monodisperse resin; they permit faster elution and regeneration times with reduced back pressure.