Article
Polymer Science
Menghe Xu, Yongzheng Liu, Wenmin Pang, Yao Pan, Min Chen, Chen Zou, Chen Tan
Summary: Two alpha-diimine nickel dimethyl complexes with different steric hindrance effects were synthesized and characterized. Organoboron cocatalysts B(C6F5)3 or [Ph3C][B(C6F5)4] can activate these complexes for ethylene polymerization without the need for any organoaluminium cocatalysts or scavengers. B1 exhibits higher catalytic activity than B2, resulting in polyethylenes with slightly lower molecular weight, higher branching densities, and lower melting temperatures. The resulting polyolefins also display good tensile and elastic properties. DFT calculations suggest that the counter anion derived from B1 contributes to increased stability and activity.
Article
Polymer Science
Cheng Wang, Dan Wang, Tao Xu, Qisheng Zhang, Zhisheng Fu
Summary: The effects of N-aryl para-benzhydryl substitutes on the thermal stability of catalysts were investigated in this study. The factors affecting thermal stability, such as steric effect, electronic effect, stability of five-membered coordination ring, and N-aryl bond rotation, were systematically analyzed. The results showed that the introduction of large steric hindrance groups at the N-aryl para-position hindered the rotation of the N-aryl bond, leading to improved catalyst thermal stability. The obstacle effect weakened with the increase of ortho-substituent size.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Polymer Science
Zahra Issaabadi, Hassan Arabi, Majid Karimi
Summary: In this study, a series of a-diimine Ni(II) complexes with camphyl backbone and various electron-donating and withdrawing substituents were synthesized and examined as catalysts for ethylene polymerization. The synthesized camphyl-based ligands were characterized by various spectroscopic techniques. The formation of the Ni(II) complexes was confirmed by spectroscopic analysis. The ligand electronic effect on the catalytic activity of Ni(II) complexes in ethylene polymerization was systematically investigated. All synthesized complexes exhibited high activity in ethylene polymerization.
POLYMERS FOR ADVANCED TECHNOLOGIES
(2023)
Article
Biochemistry & Molecular Biology
Xin Ma, Yixin Zhang, Zhongbao Jian
Summary: The unsymmetrical strategy is an effective and widely used method in the design of alpha-diimine nickel(II) and palladium(II) catalyst systems. The constructed unsymmetrical nickel and palladium alpha-diimine catalysts showed the ability to polymerize ethylene in a broad temperature range. The activity and polymer characteristics could be modulated by the reaction temperature.
Article
Chemistry, Applied
Jie Wu, Pei Li, Juan Zhang, Zhengquan Dong, Wu Li, Muhammad Sohail Bashir, Yougui Li, Fuzhou Wang
Summary: A class of nickel (II) complexes with variable electronic nature were synthesized and characterized. X-ray crystallography analysis showed that these complexes have a distorted tetrahedral geometry and can be used for chain-walking polymerization to obtain highly active and high molecular weight branched polymers.
APPLIED ORGANOMETALLIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Weiqing Lu, Hui Wang, Weigang Fan, Shengyu Dai
Summary: In this study, a bulky hybrid catalyst was designed and synthesized, which exhibited high activity and efficient copolymerization performance in the polymerization of ethylene. The hybrid catalyst generated highly branched polyethylenes with high molecular weights, showing advantages over the corresponding symmetrical catalysts.
INORGANIC CHEMISTRY
(2022)
Article
Polymer Science
Jian Xia, Ying-Feng Han, Shuqing Kou, Yixin Zhang, Zhongbao Jian
Summary: A series of flexible cyclohexyl/rigid aromatic phosphine-sulfonate palladium and nickel catalysts were designed and synthesized in this study. The steric effect of alkoxy substituents in the catalysts plays an important role in tuning polymer molecular weight and co-monomer incorporation in copolymers. The research demonstrated the high molecular weight and catalytic activity achieved by the catalysts in ethylene polymerization and copolymerization with polar monomers.
EUROPEAN POLYMER JOURNAL
(2021)
Article
Chemistry, Applied
Hongwei Peng, Shuaikang Li, Gen Li, Shengyu Dai, Mingjun Ji, Zhe Liu, Lihua Guo
Summary: The addition of bulky rotation-restricted substituents into iminopyridyl Ni (II) and Pd (II) catalysts was shown to effectively retard chain transfer, resulting in high molecular weight polyethylene or ethylene-MA copolymers with high MA incorporation ratio. Systematic studies on the (co)polymerization behavior as a function of rotation-restricted substituent variations led to the successful synthesis of various molecular weight polyethylene and ethylene-MA copolymer products.
APPLIED ORGANOMETALLIC CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Hui Wang, Weiqing Lu, Mingmin Zou, Shengyu Dai
Summary: Recently, polyolefin thermoplastic elastomers can be directly obtained via alpha-diimine nickel-catalyzed ethylene chain walking polymerization using ethylene as a single feedstock. A range of new bulky acenaphthene-based alpha-diimine nickel complexes were constructed and applied to ethylene polymerization. The activated nickel complexes exhibited good activity and produced polyethylene with high molecular weight and proper branching densities.
Article
Chemistry, Physical
Igor E. Soshnikov, Nina V. Semikolenova, Anna A. Bryliakova, Artem A. Antonov, Konstantin P. Bryliakov, Evgenii P. Talsi
Summary: A new room-temperature stable diamagnetic nickel complex has been discovered. Through H-1, H-2, and C-13 NMR spectroscopy and DFT calculations, this species has been identified as an antiferromagnetically coupled homodinuclear complex. Its behavior in the reaction solution is analogous to the resting state of nickel catalyzed ethylene polymerization.
Article
Chemistry, Multidisciplinary
Zhanshan Ma, Mengli Xu, Ningning Zhu, Chen Tan, Changle Chen
Summary: Heterogenization can improve the thermal stability and product morphology control of olefin polymerization catalysts, which are important parameters for industrial polyethylene production. In this study, alpha-diimine nickel catalysts with -OH or -ONa anchoring groups were designed and prepared to enable facile heterogenization on silica. The heterogeneous catalysts exhibited enhanced thermal stabilities and high catalytic activity, resulting in improvements in polymer morphology control, catalytic activity, and polyethylene molecular weight.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Polymer Science
Shengyu Dai, Gen Li, Weiqing Lu, Yudan Liao, Weigang Fan
Summary: The introduction of bulky ortho-steric substituents into alpha-diimine Ni(ii) and Pd(ii) species has been demonstrated to effectively retard chain transfer in olefin polymerization. The use of rotationally restricted dibenzosuberyl substituents can further suppress chain transfer and increase the molecular weight of polyethylene in ethylene polymerization.
Article
Chemistry, Inorganic & Nuclear
You Ge, Shuaikang Li, Weigang Fan, Shengyu Dai
Summary: In this study, novel α-diiminenickel and -palladium complexes containing flexible 8-alkylnaphthyl were investigated for their catalytic performance in ethylene polymerization. The nickel complexes displayed high activity and generated branched polyethylenes with broad or bimodal molecular weight distributions, while the palladium complexes showed moderate activity, producing highly branched polyethylenes with narrow molecular weight distributions. Additionally, the palladium complexes achieved highly branched E-MA copolymers with considerable MA incorporations, indicating their potential in copolymerization reactions. Compared to their rigid 8-arylnaphthyl counterparts, the flexible 8-alkylnaphthyl complexes exhibited significantly improved activity and produced lower or comparable molecular weight polyethylenes or E-MA copolymers.
INORGANIC CHEMISTRY
(2021)
Article
Polymer Science
Handou Zheng, Yinwu Li, Wenbo Du, Chi Shing Cheung, Donghui Li, Heng Gao, Huiyun Deng, Haiyang Gao
Summary: In this study, open box-like α-diimine dibromonickel complexes were synthesized and their role in ethylene polymerization was investigated. The complexes showed enhanced activity and thermal stability, and produced lightly branched polyethylenes.
Article
Chemistry, Multidisciplinary
Dung Nguyen, Shengguang Wang, Lars C. Grabow, Eva Harth
Summary: This work explains a paradox observed in the polymerization of alpha-olefin using palladium-diimine catalysts. The study reveals a novel mechanistic pathway for Pd(II)-diimine complexes, which provides a comprehensive understanding of the phenomenon.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Changwen Hong, Zihao Wang, Hui Jiang, Guifu Si, Maoping Song, Changle Chen
Summary: Brookhart-type α-diimine nickel and palladium catalysts have been extensively studied, but their heterogenization has received less attention. In this study, a trifluoroborate potassium substituent was introduced on an α-diimine framework. The ionic nature of trifluoroborate potassium strengthened the interaction between the α-diimine nickel complex and SiO2 support, while its electron-donating property enhanced the catalyst stability and polyethylene molecular weight.
CHINESE CHEMICAL LETTERS
(2023)
Article
Polymer Science
Daohong Liao, Ao Chen, Wenmin Pang, Chen Tan, Muhammad Sohail Bashir
Summary: Metal-free photocontrolled atom transfer radical polymerization of 1,2-disubstituted olefin monomers has been successfully demonstrated in this study. The combination of commercial dye EY and cocatalyst PMDETA showed controlled and selective ATRP of various N-alkyl substituted MI monomers. Moreover, successful copolymerization of MI and St was achieved using a continuous flow process, offering technical advantages for potential large-scale applications.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Jie Li, Dan Peng, Chen Tan, Changle Chen
Summary: In this contribution, an outer-shell self-supporting strategy was designed to heterogenize nickel catalysts on different fillers via precipitation homopolymerization of ionic cluster type polar monomer. These catalysts demonstrated high activity, good product morphology control, and stable performances in ethylene polymerization and copolymerization. Moreover, various polyolefin composites with great mechanical and customized properties can be efficiently synthesized.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Polymer Science
Wen Cai, Yongshuang Huang, Jie Li, Gang Yang, Fuzhou Wang, Guifu Si, Chen Tan
Summary: High catalyst loading in epoxy-based vitrimers often leads to catalyst migration, pollution, and decreased mechanical properties. In this study, a biomass zinc carboxylate is used as a multifunctional catalyst, which not only catalyzes curing and transesterification reactions but also becomes part of the crosslinked network, resulting in enhanced tensile properties. Moreover, the amphiphilic structure of this zinc carboxylate allows it to be used as a compatibilizer for vitrimer-based composites, enabling improved tensile strength.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Yan-Bing Wang, Chenlong Nan, Weize Zhuo, Chen Zou, Hui Jiang, Xin-Qi Hao, Changle Chen, Mao-Ping Song
Summary: The introduction of O-donor groups on amine-imine ligands leads to the synthesis of a series of nickel complexes, which exhibit high catalytic activities and produce polyethylene elastomers with high molecular weight. Moreover, these nickel complexes can also catalyze the copolymerization of ethylene with various functional monomers to prepare functionalized polyolefins.
INORGANIC CHEMISTRY
(2023)
Article
Polymer Science
Somayyeh Sadat Afi Kheljani, Khadijeh Didehban, Mohammad Atai, Changle Chen, Naeimeh Bahri-Laleh
Summary: In this research, the functionalization of easily available polyalphaolefin (PAO) based resins was achieved through copolymerization and further modification. The microstructure of the synthesized and modified resins was analyzed using various analytical methods. The resulting macromer showed a hydrophilic nature and had potential applications in tissue engineering.
JOURNAL OF POLYMER RESEARCH
(2023)
Article
Polymer Science
Dan Peng, Menghe Xu, Chen Tan, Changle Chen
Summary: In this study, an emulsion polymerization strategy was used to heterogenize imino-based nickel olefin polymerization catalysts on solid supports. Polymeric microspheres were prepared through emulsion copolymerization, and the resulting heterogeneous nickel catalysts exhibited excellent properties in ethylene polymerization and copolymerization. The catalytic properties could be controlled by adjusting the comonomer type, composition, and particle size. This strategy allowed for product morphology control, avoided reactor fouling, and generated polyethylene products with minimal inorganic contamination. Furthermore, the introduction of polymer microspheres improved the mechanical and surface properties of polyolefin products.
Article
Polymer Science
Menghe Xu, Ao Chen, Wu Li, Yougui Li, Chen Zou, Changle Chen
Summary: Introducing polar biomass groups into polyolefins improves their nonpolar nature and aligns with sustainable development. Researchers have developed an efficient method to produce polar functionalized polyolefins with high biomass content. By utilizing phosphine-sulfonate palladium-catalyzed copolymerization reactions, bioresourced comonomers with oleyl and cinnamyl groups are inserted into the polyolefins.
Article
Materials Science, Multidisciplinary
Yongshuang Huang, Jie Li, Meizhou Qi, Guifu Si, Chen Tan
Summary: The in situ modification of isoprene rubber by introducing sacrificial bonds during vulcanization has been investigated. The sacrificial bonds were formed by introducing hydrogen bonds and metal-ligand motifs, becoming part of the vulcanized rubber network. The addition of three component modifiers and their molar ratio greatly influenced the mechanical properties of the vulcanized rubber. Under external load, the sacrificial bonds preferentially ruptured, resulting in high fracture energy.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Chen Zou, Chen Tan, Changle Chen
Summary: Polyolefins are commonly used synthetic polymers, but their limited compatibility with polar materials has hindered their application in certain fields. Transition-metal-catalyzed copolymerization of olefin and polar functionalized monomers allows for the synthesis of polar-functionalized polyolefin materials with improved properties. Heterogenization strategies for the synthesis of high-performance heterogeneous nickel catalysts have been developed, offering better control over product morphology and improved polymerization processes.
ACCOUNTS OF MATERIALS RESEARCH
(2023)
Article
Multidisciplinary Sciences
Chen Zou, Quan Wang, Guifu Si, Changle Chen
Summary: Polar bimodal polyethylene is demonstrated as a potential solution to the trade-off between catalytic activity and polymer molecular weight caused by polar groups in catalysts. Three synthetic routes are investigated to achieve high miscibility between the polar and non-polar fractions, with the co-anchoring strategy being the most effective. This produces polyolefin materials with excellent properties for various applications.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Nan Nie, Yizhan Wang, Chen Tan, Min Chen, Dan Peng
Summary: In this study, a series of oxazole-based nickel complexes were synthesized and used to prepare hyperbranched ethylene oligomers. The catalytic performance could be modulated by adjusting the electronic and steric effects of the nickel catalysts. These nickel complexes could also catalyze the copolymerization of ethylene and polar monomers, generating polar hyperbranched oligomers.
JOURNAL OF CATALYSIS
(2023)
