Synthesis and characterization of novel soluble polyimides from an unsymmetrical diamine bearing trifluoromethyl, quinoxaline and anthraquinone pendent groups

PIs, an important high-performance plastic, have been studied and developed for many years from the viewpoints of both scientific and technical interests because of their desirablephysical and chemical characteristics and morphological properties. Despite their outstanding properties, most ofaromatic PIs have high melting or glass-transition temperatures (Tg) and are insoluble in most organic solvents because of their rigid backbones and strong interchaininteractions. These properties make them generally intractable or difficult to process, thus limiting their applications in somefields. For such difficulties to be overcome, polymer structure modification becomes necessary. Solubilization of the PIs has been targeted by several methods, such as introduction offlexible linkage , bulky units in the polymer backbone, bulky pendent substituents , or noncoplanar moieties [1,2]. In short,this work was aimed at the improving the solubility of aromatic PIs with high thermal properties by the introductionof flexible linkages, quinoxaline, anthraquinone and fluorinecontaininggroups into polymer backbones. The resulting PIs were fully characterized by inherent viscosity measurements,solubility tests, FT-IR, 1H, 13C NMR spectroscopy, DSC , TGA and CV analysis.