Fundamental perspectives on development of conductive blends based on quaternized polysulfone: Optical and dielectric response
Anca Filimon, Adina Dobos
Proceedings of The 21st International Electronic Conference on Synthetic Organic Chemistry
New blends based on ionic polysulfones for advanced applications, derived from quaternized polysulfone and cellulose acetate phthalate, were prepared. The optical and dielectric response was investigated according to chemical and microstructural aspects. All studied films develop two relaxation processes, i.e., γ and β relaxation, involving different enthalpy and entropy contributions induced by their chemical structures. Moreover, the electrical conductivity of the studied blends can be
... ed in terms of band conduction mechanisms through band gap representation. The outcomes highlight the electrical performances and importance of new polysulfone blends uses as good candidates for ionic exchange membranes in industrial applications. Proceedings 2017, 1, x FOR PEER REVIEW 2 of 12 modification, especially the chloromethylation [9,10] and quaternization reactions [11, 12] , and specific design techniques through the introduction of another polymer in the blend  allow a compromise between the hydrophobicity and hydrophilicity, leading to materials with improved properties suitable for targeted applications. Additionally, to enhance the membranes properties, as well as for better electrical, thermal and mechanical characteristics, polymer blend is an efficient concept. From this perspective, the direct blending of the functionalized polysulfone containing quaternary ammonium groups (PSFQ) with cellulose acetate phthalate (CAP) has been used as strategy to develop new conductive blends based on polysulfone with predictable and controlled properties for applications as ionic exchange membranes. It is assumed that the quaternization effect and choosing of an appropriate additive significantly improve the ionic conductivity and also could optimize the dielectric properties required by the ionic exchange membrane. Therefore, ionic polysulfone (PSFQ) obtained by the quaternization reaction of chloromethylated polysulfone (CMPSF) with tertiary amine, N,N-dimethylbutylamine (DMBA), leads to significant improvements besides the hydrophilicity, flexibility, biocompatibility, and tensile strength, the transparence features and electrical conductivity. Additionally, CAP choosing as hydrophilic and pore-forming additive represents an important tool in the workability and membrane performance. Although the blends based on polysulfones were previous investigated for membrane applications , in literature no report concerning the effects induced by the structural and compositional characteristics of the polymer blends on the optical and dielectric properties is available. In order to elucidate these aspects, optic measurements and dielectric spectroscopy analysis, are used in the study of the quaternized polysulfone/cellulose acetate phthalate blend. Therefore, the main objective of this research is to evaluate some key parameters, such as the absorption coefficient and dielectric constant of films from analyzed blend on a wide frequency range, influenced not only by the structure and nature of the polymers, but also by the composition and preparation methods. Moreover, the study realized on PSFQ/CAP blend provides a new insight on analysis and understanding of the polarization and conductivity mechanisms by designing desired conditions of transparency, improved electron interactions, and conductivity proper for better electrical performances required by the ionic exchange membranes.