Aromatic polyesters containing different content of Thioether and methyl units: facile synthesis and properties

A series of aromatic polyesters containing thioether units were successfully synthesized in this paper. Two kinds of aromatic dichloride, (4,4’-thiodibenzoyl chloride (T-DC) and 4,4’-bis(4-chloroformylphenylthio)benzene (BPB-DC) with different sulfur content were prepared and reacted with bisphenol through interfacial reaction. These four kinds of aromatic polyesters were found to have excellent thermal and mechanical properties. Their glass transition temperatures (T_g) were in the range of 161.2–216.9 °C, the initial degradation temperatures (T_d) was up to 400–454 °C and tensile strengths of 68.9–114.9 MPa. Additionally, these aromatic polyesters present good optical transmittance within the range of 81.19–84.54% at 450 nm. More importantly, all polyesters exhibited outstanding flame retardant properties. The limiting oxygen indexes (LOIs) were ranged from 30 to 39 and UL-94 V-0 rating can be reached via this approach. In summary, the comprehensive performance of the four designed polyesters surpassed the traditional aromatic ones such as U-100.