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

2005; American Chemical Society; Volume: 17; Issue: 7 Linguagem: Inglês

10.1021/cm048376p

1520-5002

Alfredo Mellace, James E. Hanson, Julianne C. Griepenburg,

Fuel Cells and Related Materials

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 Mw of 17 kD and a polydispersity of 2.0. Polymerization for 8.5 h at 150 °C in NMP gave a polymer with a Mw of 16 kD and a polydispersity of 1.5. Addition of 1,3,5-trichlorobenzene as a multifunctional core to the polymerizations gave reduced Mw and lower polydispersity. Addition of 1 core for every 50 monomers gave a polymer with a Mw of 8.4 kD and a polydispersity of 1.2 in DMF and a polymer with a Mw 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 Tg between 60 and 90 °C and no apparent crystallinity. The polymers prepared in DMF had higher Tgs 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 N2 atmospheres. In air, complete decomposition occurred by about 625 °C, while approximately 25% of the mass remained at 700 °C under N2. 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 Tg of the sulfone was approximately 155 °C, while by TGA the decomposition temperature was 325−375 °C in both air and N2. In air, decomposition was complete by 575 °C, while in N2 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.