Synthesis And Research Of Poly (Trimethylene Terephthalate)

Poly(trimethylene terephthalate)(PTT) is a synthetic fiber material and engineering plastic material with excellent properties. The commercialization of PTT in China is still in a scale up stage. The main factor that restricts the development of PTT falls upon the synthesized PTT with a relatively lower intrinsic viscosity not to meet the requirements of spinning. Intrinsic viscosity of synthesized PTT relates to the catalyst used in synthesis of PTT, reaction conditions, vacuum of polyerization system and so on, while the catalyst is one of the main factors affecting on the intrinsic viscosity of PTT. Therefore, one kind of catalyst was designed, prepared and applied to synthesize PTT.1,3-Propylene glycol titanate was synthesized by the reaction involving the transesterification of 1,3-propanediol with tetrabutyl titanate. The obtained cyclic metal titanates can be simply purified only by fltration in a high yield. The chemical structure was confirmed by 1HNMR technique. The best catalyst was obtained under the condition of reaction temperature 75℃, reaction time for 3h, the dropping time for 25min, and the ratio of PDO/Tetrabutyl titanate for 2.79. Both esterification time and polycondensation time were relatively short.Also, the effects of reaction conditions on the synthesis were discussed. The results showed that 1,3-propanediol titanium had high catalytic activity.The PTT with intrinsic viscosity 0.6831 dL/g can be produced under the conditions as followed:molar ratio of 1,3-propanediol to PTA of 1.8:1,1,3-propanediol titanium content based on 1 g PTA of 0.74 mg, esterification temperature 235℃, polycondensation temperature 255℃and time 1 h.