Research on Influence Factors of Surfactivity of Polyester Polyether Block Copolymer

Polyester polyether block copolymer (PPBC) was synthesized by ester-exchange and polycodensation reactions using dimethyl terephthalate (DMT), ethylene glycol (EG) and polyethylene glycol (PEG) as monomer. The effects of PEG molecular weight, mol ratio of DMT to PEG (nDMT/nPEG), temperature and time of polycondensation reaction and vacuum degree in the reaction system on the surface tension and critical micelle concentration (CMC) of PPBC aqueous solution were studied. It was found that both the molecular weight and the concentration of PEG can affect PPBC'S surface activity obviously, and the optimum synthesis condition of PPBC used as surfactant is as follows: PEG molecular weight is 1500, mol ratio of DMT to PEG is 3, temperature and time of polycondensation reaction is 260°C×1h, vacuum degree of condensation reaction is 0.03-0.05 MPa. It was proved by surface tension measurement of PPBC aqueous solution that the PPBC synthesized in this condition is a good surfactant with excellent surfactivity.