Porous polymer networks: synthesis, porosity, and applications in gas storage/separation

Three porous polymer networks (PPNs) have been synthesized by the homocoupling of tetrahedral monomers. Like other hyper-cross-linked polymer networks, these materials are insoluble in conventional solvents and exhibit high thermal and chemical stability. Their porosity was confirmed by N2 sorption isotherms at 77 K. One of these materials, PPN-3, has a Langmuir surface area of 5323 m2 g−1. Their clean energy applications, especially in H2, CH4, and CO2 storage, as well as CO2/CH4 separation, have been carefully investigated. Although PPN-1 has the highest gas affinity because of its smaller pore size, the maximal gas uptake capacity is directly proportional to their surface area. PPN-3 has the highest H2 uptake capacity among these three (4.28 wt %, 77 K). Although possessing the lowest surface area, PPN-1 shows the best CO2/CH4 selectivity among them.