Catalysts For Synthesis Of Poly (Trimethylene Terephthalate) By Direct Esterification

Polytrimethylene terephthalate (referred to as PTT) is a new type of thermoplastic polyester. PTT has superior performance in mechanical properties and chemical resistance than PET and PBT because of its high elasticity and low modulus polyester. However, the PTT which produced by local manufactureres was not ideal. The biggest problem was its low viscosity and cannot be used for industrial spinning. The intrinsic viscosity of PTT depends on the reactor, catalyst, vacuum, reaction time and reaction temperature while the catalyst is an important factor. One kind of catalyst was designed by using the sol-gel method and for the synthesis of PTT in this paper.The optimal condition for the synthesis of TiO2-SiO2catalyst was discussed. The result was:the amount of solvent was49.92mL, the amount of water was16.34g, water added dropwise over5s/dropping, the reaction temperature was65℃, the reaction time was3h, the aging time was12h, the drying time was16h, and calcined at500℃for3h.In addition, the synthesis condition of PTT was also discussed. The results showed that: the prepolycondensation time was40-45min, the condensation temperature was250℃, the reaction time was50min. The intrinsic viscosity of PTT was0.849dL/g under these conditions.