Study On Synthesis Of Poly (Trimethylene Terephthalate) With Titanium Catalyst

Poly trimethylene terephthalate (PTT) is a new type of thermoplastic polyester materials with a good development prospect. Due to its excellent performances such as unique spiral structure, as soft as nylon, as fluffy as acrylic fiber, as stain-proof as terylene and its inherent property such as flexibility, moderate glass transition temperature and good processing properties, PTT has been widely applied in the field of carpet, nonwovens cloth, etc.Catalytic system is the key part of synthesis of PTT. As a result, it is very important to develop a catalytic system with good performances by designing catalyst composition and structure and preparing in a special method.In this paper, titanium catalytic system for the synthesis of PTT is studied. Several titanium catalysts are prepared and the processes of preparing catalyst as well as the effects of the catalysts on the synthesis of PTT are investigated. Finally, a best catalyst is selected.Three catalysts (titanium 2-oxidoacetate, MoO3-supported TiO2-Al2O3 mixed oxides, mesoporous "core-shell" mixed catalytic system) are prepared in this research. The titanium 2-oxidoacetate catalytic system is the best one for the synthesis of PTT with a high activity and high viscosity of the products. The optimum process conditions of synthesis PTT are as follows:the amount of catalyst:0.74 mg/g PTA,1,3-PDO/PTA ratio:1.8, the esterification reaction temperature:245℃, polycondensation temperature:255℃, poly-condensation time: 90 min.