Synthesis And Properties Research Of Poly (Trimethylene Terephthalate)

Poly(trimethylene terephthalate) is a new kind of high performance polyester, because there are three methylenes which existing in macromolecular chain will generate"Effect of odd carbon" and lead to different performance from PET and PBT. Thus the PTT polyester cannot only have the rigidity of PET and the flexible of PBT synchronously, but doubles the virtues of PET and PA such as high tensile elasticity, fluffy, easier process and dye etc. So PTT polyester has the worthiness of development and the application in the textile, carpet fibers, engineering plastics, and film and other areas. In this paper, use direct esterification melt polycondensation route to synthesize the PTT; IR,1H NMR were used to characterize it.Types of catalytic amount of catalyst, reaction temperature, reaction time, molar ratio of raw materials, amount of stabilizer and other process conditions were studied in the process of PTT synthesis and effect the final product of PTT polymer resin of the basic performance. The optimal PTT synthetic process conditions:esterification temperature 235～245℃PDO:PTA mole ratio of 1.4:1, the amount of catalyst tetrabutyl titanate 500ppm. condensation temperature 260℃, polycondensation time 120min.Under this conditions, the synthesized PTT resin intrinsic viscosity is 0.96dL/g, with high value industrial applications, can be used for spinning and molding. By DSC and TG study the melting behavior and stability of PTT. found that PTT is a semi-crystalline polymer, and have double melting peaks in the melting process; PTT have worse stability than PET, but relatively similar with PBT.By DSC study the isothermal crystallization and non-isothermal crystallization kinetics of PTT. The results showed that:In the isothermal crystallization process of PTT, Avrami exponent n between 1.41 to 1.99, isothermal crystallization behavior of PTT has a strong dependence on temperature. With the increasement of crystallization temperature, semi-crystallization time t1/2 prolong, crystallization rate constant k value decrease, crystallization rate decline; In the non-isothermal crystallization process, with the increasement of cooling rate, Zc increase, t1/2 decrease.The rheological properties of PTT melt were studied by capillary rheometer. PTT melt possess Non-Newtonian fluid characteristic, with the increasement of shear rate, the apparent viscosity decrease, show a typical shear thinning phenonmenon.