以钛酸四丁酯、柠檬酸为基本原料制备了一种新型络合钛聚酯催化剂，并将其与纳米凹凸棒土(ATP)复合，得到一类复合催化剂，对络合钛及复合催化剂分别进行了红外和透射电镜表征，证实了金属钛与柠檬酸配体发生了络合，复合催化剂具有良好的分散状态。通过催化聚酯反应对络合钛及多种复合催化剂的性能进行了评价，结果表明：与常规聚酯催化剂Sb2O3相比较，络合钛催化活性约为Sb2O3的6倍，但产品色相b值较高(大于15.60)；将络合钛与纳米凹凸棒土以2：1的质量比负载后，催化反应得到的聚酯b值从16.30降为3.79，综合反应速度和聚酯色相的结果，认为络合钛与凹凸棒土的合适质量配比为5：2。此外，讨论了复合催化剂对聚酯物化性能的影响，通过DSC、TGA等测试手段，发现络合钛复合纳米凹凸棒土作催化剂制备的聚酯的结晶温度比Sb2O3催化制备的聚酯要高7℃以上，熔点高6℃左右，二甘醇含量更低，其热降解性能相近。%A Ti-complex catalyst for polyester synthesis was prepared with tetrabutyl titanate and citric acid as starting materials. Then, the catalyst was supported on nano-attapulgite (ATP), and a series of composite catalysts were obtained and characterized by infrared spectroscopy (IR) and TEM. The IR and TEM results show that the Ti is complexed with citric acid, and the Ti-complex could disperse on the ATP to increase the catalyst surface. The catalytic performances of the prepared catalysts were evaluated by the polyester reaction, and the results show that the activity of Ti-complex catalyst is 6 times higher than that of the commonly used catalyst Sb2O3. However, using Ti-complex catalyst, the hue b (more than 15.6) of the produced polyester is larger than that of polyester produced by using Sb2O3 as catalyst. After the Ti-complex catalyst was supported on nano-attapulgite with mass ratio of 2:1, the hue b of polyester is decreased from 16.30 to 3.79. Based on a comprehensive consideration of reaction rate and polyester color, the suitable mass ratio of Ti-complex vs. nano-attapulgite is 5:2. Besides, the influences of different catalysts on the physical and chemical properties of the produced polyester were discussed through DSC and TGA, which reveal that the crystallization temperature of polyester produced by using the Ti-complex catalysts increases over 7℃ higher than that of polyester produced by using Sb2O3 as catalyst. The content of diethylene glycol in polyester produced by using composite catalyst decreases, and the thermal performances are close to that of the polyester produced by using Sb2O3 as catalyst.
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