Synthesis and characterization of poly(p-arylene sulfide ketone/Schiff base) copolymers

Poly(p-arylene sulfide ketone/Schiff base) copolymers (PASK/SB) were prepared by solution polycondensation of 4,4′-diflurobenzophenone (DFBP) and N-phenyl(4,4′-diflurodiphenyl) ketimine (DFBI) with sodium sulfide in the presence of sodium hydroxide under normal pressure. Elemental analyses, FT-IR, NMR, DSC, TGA and XRD were used to characterize the resultant copolymers. It was found that the copolymers had good thermal properties with glass transition temperature (T _g) of 155.0–172.0°C, melting temperature (T _m) of 298–344°C, 5% weight loss temperatures (T _d) of 471.0–501.5°C. These copolymers were almost amorphous with the content of DFBI beyond 30%. The polymer with 100% DFBI had excellent solubility, and it could dissolve in some solvents such as tetrahydrofuran (THF) and N-methyl-2-pyrrolidone (NMP). The processability of polymers was improved. Meantime the viscosity of PASK made from hydrolysis of PASK/SB (H-PASK/SB) was greatly improved from 0.135 dL/g to 0.605 dL/g.