There are two approaches to obtain polystyrene sulfonate: either sulfonating the styrene monomer & then polymerizing it "called pre-sulfonation" or sulfonating the polystyrene "called post-sulfonation". As you will see in the given reference, pre-sulfonation is preferred by the authors (which is not my view).
My students & I did post-sulfonation "not for research but for scientific fares" in order to show other students & interested visitors how an ion-exchange resin is prepared. Wishing you success.
Thanks for the information. I'm particularly interested in obtaining the resin highly crosslinked. Perhaps I'll need to make it myself. Science fairs are great!
I think they are commercially available for exemple from sigma aldrich. The most known are amberlites (or duolites) and colligun. Also it is not difficult to prepare it by modulating the DVB concentration. Regards