Catalan referendum, explained: What's behind the push to break from Spain?
In addition to economic difference, Cultural difference, especially linguistic difference, may boost motivation toward Independence. Similar case can be seen elsewhere in the world.
Though independence from a neighboring country will result in a lot of changes on social systems, I doubt it also happens in Catalan area. I think there would be no barrier between Catalona and Spain, because Spain is a member of EU and Catalan nation will also be.