Abstract:

Titanium-based polyester catalysts are ideal substitutes for traditional antimony-based catalysts due to their high catalytic activity and environmental friendliness. In order to prepare titanium polyester catalyst with hydrolysis resistance, good dispersibility and stable catalytic performance, TiOC@SiO₂ catalyst was prepared by reverse microemulsion method. A layer of siloxane was coated on the surface of titanium containing organic compound to stabilize the catalytic activity. The morphology, structure and properties of TiOC@SiO₂ were characterized by various modern characterization methods, and its catalytic performance in the synthesis of polyethylene terephthalate (PET) was evaluated. The results showed that the TiOC@SiO₂ catalyst had a core-shell spherical structure with a particle size of about 200nm, but no Ti—O—Si bond, and a Ti content of 6.95%. The structure and catalytic activity of TiOC@SiO₂ catalyst remained unchanged at 90℃ for 2h. The composite structure significantly improved the hydrolysis resistance of the titanium organic compounds and dispersibility. In the polyethylene terephthalate synthesis experiment, with only 5μg/g TiOC@SiO₂ added and polycondensation at 270℃ for 92min, polyester with intrinsic viscosity of 0.677dL/g, terminal carboxyl content of 14.4mol/t and b value of 2.16 was prepared.

Key words: catalyst, polymerization, nanoparticles, polyester, catalytic performance

摘要：

钛系聚酯催化剂因催化活性高、环境友好等优点，是传统锑系聚酯催化剂的理想替代品。为了制备出耐水解性好、分散性好、催化性能稳定的钛系聚酯催化剂，采用反相微乳液法，制备得到核壳结构催化剂TiOC@SiO₂。在钛有机化合物的表面包覆一层硅氧烷，以此稳定钛有机化合物的催化活性。利用多种现代表征方法对TiOC@SiO₂的形貌、结构和性能进行了表征分析，并探究其在合成聚对苯二甲酸乙二醇酯（PET）中的催化性能。研究结果表明，TiOC@SiO₂催化剂为粒径约200nm的核壳球形结构，无Ti—O—Si键，钛含量为6.95%。TiOC@SiO₂催化剂在90℃下水浴2h后，其结构和催化活性保持不变，复合结构显著提高了钛有机化合物的耐水解性和分散性。在聚酯合成实验中，仅添加5μg/g TiOC@SiO₂，在270℃下缩聚反应92min，即可制备出特性黏度为0.677dL/g、端羧基含量为14.4mol/t、b值为2.16的PET。

关键词: 催化剂, 聚合, 纳米粒子, 聚酯, 催化性能