Lan Tianyu, Chen Liduo, Zhang Na, Wang Jun
College of Chemistry and Chemical Engineering, Northeast Petroleum University, Heilongjiang, China.
Heilongjiang Provincial Key Laboratory of Polymeric Composite Materials,Qiqihar University, China.
Des Monomers Polym. 2021 Jan 18;24(1):13-21. doi: 10.1080/15685551.2020.1868666.
The 1.0 G dendrimer (CHNO),3,5-di-tert-butylsalicylaldehyde and TiCl · 2THF were used as the synthetic materials, and the dendritic salicylaldehyde imide ligand with substituent hindrance and its titanium catalyst were synthesized by the condensation reaction of schiff base. The structure of the synthesized products was characterized by infrared spectroscopy, nuclear magnetic resonance hydrogen spectroscopy, ultraviolet spectroscopy, electrospray mass spectrometry, and inductively coupled plasma mass spectrometry, The actual structure is consistent with the theoretical design structure. Activated methylaluminoxane (MAO) was used as a catalyst precursor for ethylene polymerization in the process of ethylene catalytic. The effects of ethylene polymerization were studied in terms of the Al/Ti molar ratio, reaction time, reaction temperature, polymerization pressure, and ligand structure of the catalyst. The results show at the reaction temperature of 25°C, the reaction time was 30 min, and the ethylene pressure was 1.0 MPa and Al/Ti was 1,000, the catalytic activity can reach 78.56 kg PE/(mol Ti.h). Furthermore, high-temperature GPC-IR, DSC, and torque rheometer were used to characterized the microstructure, thermal properties, and viscoelastic state of polyethylene samples obtained. The results showed that the product was ultra-high-molecular-weight polyethylene.
以1.0 G树枝状大分子（CHNO）、3,5-二叔丁基水杨醛和TiCl₄·2THF为合成原料，通过席夫碱缩合反应合成了具有取代基位阻的树枝状水杨醛亚胺配体及其钛催化剂。采用红外光谱、核磁共振氢谱、紫外光谱、电喷雾质谱和电感耦合等离子体质谱对合成产物的结构进行了表征，实际结构与理论设计结构一致。在乙烯催化过程中，采用活化甲基铝氧烷（MAO）作为乙烯聚合的催化剂前驱体。从Al/Ti摩尔比、反应时间、反应温度、聚合压力和催化剂配体结构等方面研究了乙烯聚合的影响。结果表明，在反应温度为25℃、反应时间为30 min、乙烯压力为1.0 MPa且Al/Ti为1000时，催化活性可达78.56 kg PE/(mol Ti·h)。此外，采用高温凝胶渗透色谱-红外光谱联用仪、差示扫描量热仪和转矩流变仪对所得聚乙烯样品的微观结构、热性能和粘弹性状态进行了表征。结果表明，产物为超高分子量聚乙烯。
