Synthesis and Application of Sulfonated Polyester Polyols with Low Acid Value
Sulfonated polyester polyols were key raw materials in synthesis of sulfonate type waterborne polyurethane(WPU)with hydrophilic groups in soft segment.The low acid value(Av)was an important technical indicator of sulfonated polyester polyols as well as a key factor that affecting the synthesis of WPU.Several sulfonated polyester polyols were syn-thesized by transesterification/esterification-melt polycondensation method by using sodium dimethyl isophthalate-5-sulfon-ate as a hydrophilic monomer.The structure of the products was characterized and the influence of condensation pressure on Av was investigated with emphasis.According to the saturated pressure of diol at the polycondensation temperature,a so-called"three-stage pressure control method"was proposed and a variety of sulfonated polyester polyols with Av＜1～2 mg KOH/g were synthesized by gradually reducing the pressure without the aid of solvent or water-carrying agent.The devel-oped technology was suitable for the synthesis of different kinds of polyester polyols and could be scaled up.Low Av sulfon-ated poly(butanediol adipate)had excellent hydrophilicity and water dispersion,which could form water dispersions with blue light and particle size＜100 nm,and polyurethane film with enough tensile strength(≥30 MPa)was successfully syn-thesized from it.
chemical processchemical thermodynamicspolyester polyolssodium dimethyl isophthalate-5-sulfonatelow acid valuewaterborne polyurethanemechanical property
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