Synthesis and characterization of nitrated and aminated poly(phenylene sulfide) derivatives for advanced applications

Nitrated and aminated poly(phenylene sulfide) (PPS) derivatives with different extent of modification were synthesized in a one-pot reaction in suspension. Their substitution degree was determined from both elemental analysis and TGA curves. FT-IR and NMR spectra demonstrated the effectiveness of the functionalization reactions, showing the appearance of bands related to the substituent groups. A progressive reduction in thermal stability was observed as the number of functional groups increased. Aminated derivatives were thermally less stable and exhibited higher solubility in aprotic polar solvents than the corresponding nitrated polymers. DSC thermograms revealed a diminution in the crystallization temperature and a rise in the glass transition with increasing functionalization degree, since the presence of substituent groups inhibits the rotation of consecutive elements of the polymer chain. The level of crystallinity decreased upon increasing chain modification, as evidenced from X-ray diffractograms. The steric hindrance of the substituents disrupts the chain packing, leading to smaller crystals. These derivatives are expected to have applications in electromembranes and as matrix materials for the fabrication of high-performance composites suitable for structural and non-structural components.