Poliviniliden florür temelli aşı kopolimeri

During the last three decades, many special fluoropolymers have been developed, due to their chemical resistance, weathering elements and oxidants, low surface free energy properties and also oil/water repellence due to their hydrophobic properties. Fluoropolymers represent a rather specialized group of polymeric materials. Amphiphilic fluorinated graft copolymers are of considerable interest for proton exchange membrane applications. Poly(vinylidene fluoride) (PVDF) has commercial importance due to its excellent properties as well as for special properties such as resistance. Because of its commercial importance, various synthetic approaches for the preparation of graft copolymers from PVDF have been reported. The limitations of the commercial fuel cell membranes are a susceptibility to chemical degradation at elevated temperature, including poor ionic conductivities at low humidity or elevated temperatures, finally, membrane expensiveness. Thus synthesizing alternative membranes for fuel cells is still a challenging goal. Atom transfer radical polymerization (ATRP) is controlled free radical polymerization technique. The technique also permit advanced fluorinated polymers to be synthesized. They are one of the best route for the preparation of these well-defined amphiphilic graft copolymers with controlled molecular weight, polydispersity, terminal functionalities, and chain architecture composition due to the relavite ease of synthesis and their compability with a wide range of solvents. Here are reported that PVDF backbone was grafted by methyl methacrylate (MMA) and 3-sulfopropyl methacrylate potassium salt (SPMAK) by using atom transfer radical polymerization (ATRP). First, PVDF was functionalized to obtained ATRP macro-initiator by 2-bromo-2-methylpropionyl bromide via lithiation reaction. Second MMA and SPMAK was grafted to PVDF backbone using PVDF-Br as a macroinitiator by ATRP. Then the graft copolymers were characterized by FT-IR, 1H NMR and DSC methods. Then the proton conductivity and thermal stability in grafted polymer have been investigated for PVDF based membranes.