Hyperbranched Poly(phenylene sulfide) and Poly(phenylene sulfone)

Hyperbranched poly(phenylene sulfide) was prepared from 3,4-dichlorobenzenethiol. This monomer was treated with potassium carbonate in an amide solvent, either N, N -dimethylformamide (DMF) or N -methylpyrrolidone (NMP). Polymerization for 24 h at 100 °C in DMF gave a polymer with a M w of 17 kD and a polydispersity of 2.0. Polymerization for 8.5 h at 150 °C in NMP gave a polymer with a M w of 16 kD and a polydispersity of 1.5. Addition of 1,3,5-trichlorobenzene as a multifunctional core to the polymerizations gave reduced M w and lower polydispersity. Addition of 1 core for every 50 monomers gave a polymer with a M w of 8.4 kD and a polydispersity of 1.2 in DMF and a polymer with a M w of 13 kD and a polydispersity of 1.3 in NMP. The polymers were primarily characterized by size-exclusion chromatography with light-scattering detection (which provided the molecular weights and distributions) and by thermal methods. Differential scanning calorimetry (DSC) revealed that the hyperbranched PPS was amorphous with a T g between 60 and 90 °C and no apparent crystallinity. The polymers prepared in DMF had higher T g s than those prepared in NMP. Thermogravimetric analysis revealed that the hyperbranched PPS was very thermally stable, with decomposition temperatures between 400 and 450 °C in both air and N 2 atmospheres. In air, complete decomposition occurred by about 625 °C, while approximately 25% of the mass remained at 700 °C under N 2 . The hyperbranched PPS could be oxidized to hyperbranched poly(phenylene sulfone). This material was completely insoluble, but could be analyzed by thermal methods. By DSC, the T g of the sulfone was approximately 155 °C, while by TGA the decomposition temperature was 325−375 °C in both air and N 2 . In air, decomposition was complete by 575 °C, while in N 2 about 30% of the mass remained at 700 °C. These simple, one-pot approaches to hyperbranched poly(phenylene sulfide) and hyperbranched poly(phenylene sulfone) from commercially available monomers provide an entry to many further studies and applications for these new materials.