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High Melting Point of Linear, Spiral Polyethylene Nanofibers and Polyethylene Microspheres Obtained Through Confined Polymerization by a PPM‐Supported Ziegler‐Natta Catalyst
ChemistryOpen ( IF 2.3 ) Pub Date : 2020-11-12 , DOI: 10.1002/open.202000290
Yu Xiao 1 , Xiying Dai 1 , Kui Wang 2 , Guangyuan Zhou 2
Affiliation  

In this work, different types of polyethylene (linear, spiral nanofibers and microspheres) were obtained via confined polymerization by a PPM‐supported Ziegler‐Natta catalyst. Firstly, the Ziegler‐Natta catalyst was chemical bonded inside the porous polymer microspheres (PPMs) supports with different pore diameter and supports size through chemical reaction. Then slightly and highly confined polymerization occurred in the PPM‐supported Ziegler‐Natta catalysts. SEM results illustrated that the slightly confined polymerization was easy to obtain linear and spiral nanofibers, and the nanofibers were observed in polyethylene catalyzed by PPMs‐1#/cat and PPMs‐2#/cat with low pore diameter (about 23 nm). Furthermore, the highly confined polymerization produced polyethylene microspheres, which obtained through other PPM‐supported Ziegler‐Natta catalysts with high pore diameter. In addition, high second melting point (Tm2: up to 143.3 °C) is a unique property of the polyethylene obtained by the PPM‐supported Ziegler‐Natta catalyst after removing the residue through physical treatment. The high Tm2 was ascribed to low surface free energy (σe), which was owing to the entanglement of polyethylene polymerized in the PPMs supports with interconnected multi‐modal pore structure.

中文翻译:

PPM 支持的齐格勒-纳塔催化剂通过限域聚合获得高熔点线性、螺旋聚乙烯纳米纤维和聚乙烯微球

在这项工作中,不同类型的聚乙烯(线性、螺旋纳米纤维和微球)是通过 PPM 负载的齐格勒-纳塔催化剂的限域聚合获得的。首先,通过化学反应将齐格勒-纳塔催化剂化学键合在不同孔径和载体尺寸的多孔聚合物微球(PPM)载体内部。然后,PPM 负载的齐格勒-纳塔催化剂中发生轻微且高度受限的聚合。SEM结果表明,轻微限域聚合很容易获得线性和螺旋纳米纤维,并且在PPMs-1#/cat和PPMs-2#/cat催化的聚乙烯中观察到纳米纤维具有低孔径(约23 nm)。此外,高度限域聚合产生了聚乙烯微球,这是通过其他PPM负载的高孔径齐格勒-纳塔催化剂获得的。此外,高第二熔点(T m2:高达143.3℃)是PPM负载的齐格勒纳塔催化剂通过物理处理去除残留物后获得的聚乙烯的独特性能。高T m2归因于低表面自由能 ( σ e ),这是由于在具有互连多模态孔结构的 PPM 载体中聚合的聚乙烯纠缠在一起。
更新日期:2020-11-12
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