Novel Block Copolymers As Proton Exchange Membranes for Fuel Cells and Specialty Separation Applications

Novel Block Copolymers as Proton Exchange Membranes for Fuel Cells and Specialty Separation Applications

Efficient proton exchange membranes are the crucial component for fuel cells that could power the next generation of green energy devices. The industry standard to make these membranes is Nafion®, which although it has an excellent proton exchange capacity and great thermal stability, it can be expensive to mass produce and it has some mass-transfer limitations. Our goal is to make proton exchange membranes better to Nafion®’s properties with lower costs to produce. In this study, three inexpensive monomers were used to build the polymer chain: isobutylene, styrene and methyl vinyl ether. With a combination of these monomers block copolymers were synthesized and tested their properties with various materials characterization methods. Also, other combinations of polymers such as Poly(styrene-isobutylene-styrene) (SIBS) and Poly(styrene-isoprene-styrene) (SIS) were blended to test their properties. Thermogravimetric Analysis (TGA) shows how the initiator for the Atom Transfer Radical Polymerization (ATRP) affects the overall degradation temperature of the polymer. Differential Scanning Calorimetry (DSC) tests verify how 4-chlorobenzophenone initiated polymerizations that possess a lower melting point compared to the (2-chloroethyl)benzene samples. Also, the synthesized polymer chains show an expected increase in their number average molecular weight (Mn) and change in polydispersity (PD). Polymer blends with SIS and SIBS show different properties in permeability and water swelling tests that can imply that the right blend composition can cause synergistic results with the desired properties, which can be the next step for the Poly(isobutylene styrene methyl vinyl ether) (PIB-PS-PE) synthesized polymer to be blended with premade SIS and SIBS.