Crosslinking polyimides for membrane applications: A review

This review discusses many crosslinking methods for polyimide membranes that have been described in literature. Some important properties of polyimides and their synthesis reactions are first summarized. The important (commercialized) polyimide types that are now used in membrane technology, the preparation methods available for polyimide membranes and their main applications are listed. The effects of thermal annealing of polyimide membranes are briefly discussed, before giving an extensive review of the many crosslinking methods that have been described in literature. Thermal crosslinking, UV crosslinking and a range of chemical crosslinking methods, including diol and diamine crosslinking, are discussed in detail, focusing on the actual chemistry behind the crosslinking. Also, some new, not yet fully studied, crosslinking methods are listed.