Article
Polymer Science
Wenbing Wang, Min Chen, Wenmin Pang, Yougui Li, Chen Zou, Changle Chen
Summary: Investigated two groups of norbornene comonomers: one provides additional active sites for sulfur vulcanization and the other can alter the non-polar nature of polyolefin materials. Palladium-catalyzed terpolymerization of ethylene with these comonomers yields polar-functionalized polyolefin elastomers with high molecular weight and comonomer content, possessing excellent mechanical and elastic properties.
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
Polymer Science
Weiqing Lu, Beihang Ding, Wenping Zou, Shengyu Dai
Summary: Alpha-diimine nickel-catalyzed ethylene chain walking polymerization enables the direct preparation of polyethylene thermoplastic elastomers with high activities and molecular weights. The hybrid bulky butyl-based alpha-diimine nickel complexes with unsymmetrical substituents facilitate the synthesis of significantly higher branched polyethylene with much better elastic recovery. These hybrid cationic nickel catalysts are also capable of catalyzing the copolymerization of ethylene with methyl 10-undecenoate.
EUROPEAN POLYMER JOURNAL
(2023)
Review
Polymer Science
Giorgia Zanchin, Giuseppe Leone
Summary: Polyolefins, particularly poly olefin thermoplastic elastomers (P-TPEs), are a class of materials that are easily molded, lightweight, and recyclable, making them suitable for the sustainable circular economy. Recent developments in the field have focused on the synthesis of smart materials with temporary shape storage and molecular level functionality, opening up new possibilities for applications in various industries. Challenges and opportunities for recyclable high performance and lasting P-TPEs are being addressed to meet the demands of the future.
PROGRESS IN POLYMER SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Tiantian Wang, Chunji Wu, Xiangling Ji, Dongmei Cui
Summary: The copolymerization of ethylene and fluorostyrenes using a specific scandium complex resulted in copolymers with controlled composition, exhibiting a microphase-separated structure that contributes to excellent mechanical properties. The presence of soft and hard segments in the copolymers allows for high stress values and elongation-at-break percentages, with the mechanism of copolymerization investigated through density functional theory simulations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Lukas Odenwald, Florian P. Wimmer, Nina K. Mast, Max G. Schussmann, Manfred Wilhelm, Stefan Mecking
Summary: Vitrimers combine the advantages of cross-linked materials with thermoplastic processability. Functionalized polyethylenes with cross-linkable groups were directly generated by catalytic insertion polymerization. These vitrimers exhibit excellent material properties and can be recycled due to reversible cross-linking.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Marvin Langlais, Nicolas Baulu, Severin Dronet, Charlotte Dire, Francois Jean-Baptiste-dit-Dominique, David Albertini, Franck D'Agosto, Damien Montarnal, Christophe Boisson
Summary: Block copolymers based on polyethylene (PE) and ethylene butadiene rubber (EBR) were synthesized using successive controlled coordinative chain transfer polymerization (CCTP). By employing a complex of {Me2Si(C13H8)(2)Nd(BH4)(2)Li(THF)}2 and n-butyl, n-octyl magnesium (BOMAG) as the alkylating and chain transfer agent (CTA), EBR-b-PE diblock copolymers were obtained. Furthermore, triblock and multiblock copolymers featuring highly semi-crystalline PE hard segments and soft EBR segments were synthesized with the development of a bimetallic CTA, pentanediyl-1,5-di(magnesium bromide) (PDMB). These new block copolymers form lamellar structures through crystallization-driven organization and exhibit various mechanical properties, including excellent extensibility and elastic recovery for triblock and multiblock copolymers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Polymer Science
Fan Yu, Pei Li, Mengli Xu, Guoyong Xu, Yinna Na, Shaojie Zhang, Fuzhou Wang, Chen Tan
Summary: This study investigated the influence of polyethylene glycol unit on nickel-catalyzed ethylene polymerization, finding that the molecular weight of products increased with the number of oxygen atoms on the polyethylene glycol unit. The introduction of MgCl2 support resulted in higher molecular weights and lower branch densities of polymers, with heterogeneous polymerizations generating polymers with excellent powder morphology.
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
Jiawei Chen, Wenbing Wang, Yao Pan, Dan Peng, Yougui Li, Chen Zou
Summary: In this study, direct copolymerization of plant oil-based copolymer monomers with ethylene was achieved using a dienyl phosphoribosulfonyl palladium catalyst (PO-Pd). Addition, ureido-pyrimidinone (UPy) functionalization was performed using the hydroxyl group of the polymer. The incorporation of biomass groups effectively modifies the surface and mechanical properties of the copolymers, and these newly developed polymers are ideal tougheners for gutter oil due to their excellent tunability of the self-complementary hydrogen bonding network (UPy).
Article
Chemistry, Multidisciplinary
Quan Wang, Zhao Zhang, Chen Zou, Changle Chen
Summary: In this study, a simple cocatalyst strategy was designed to enhance the catalytic properties of various nickel catalysts in ethylene polymerization and enable control over product morphology.
CHINESE CHEMICAL LETTERS
(2022)
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
Xiaoxu Li, Lidong Qin, Qaiser Mahmood, Zhixin Yu, Song Zou, Yizhou Wang, Tongling Liang, Wen-Hua Sun
Summary: Steric effects have a significant impact on the catalytic performance of alpha-diimine nickel precatalyst for ethylene polymerization. In this study, a series of new unsymmetrical 2,3-diiminobutane nickel complexes with sterically encumbered groups were synthesized and used as pre-catalysts. These complexes exhibited remarkable catalytic activities and produced highly branched polyethylene with high molecular weights and narrow molecular weight distributions when used with optimal co-catalysts. The Ni3 complex showed high thermal stability and maintained high catalytic activity even at elevated temperatures. The branching content and mechanical properties of polyethylene were also influenced by temperature.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Wang Zihao, Chen Min, Chen Changle
Summary: Since the discovery of Ziegler-Natta catalyst, significant progress has been made in catalyst design for olefin polymerization. However, the development of catalysts remains a fresh source of innovation in this field. Nickel-based catalysts show great promise in olefin polymerization due to their low cost and abundance. In this study, three unsymmetrical a-diimine nickel catalysts with different steric effects were designed and their catalytic performances in ethylene polymerization were investigated.
ACTA CHIMICA SINICA
(2023)
Article
Polymer Science
Baloji Adothu, Francis Reny Costa, Sudhanshu Mallick
Summary: A new UV-365 acceleration test was conducted to study the reliability of the newly developed TPO encapsulant and the commonly used EVA. The results showed that EVA exhibited a much higher rate of decrease in transmittance and a higher rate of increment in yellowness compared to TPO. Fluorescence imaging revealed the generation of fluorophores in EVA laminate with increasing UV dose, while no significant fluorescence was observed in TPO laminate. Raman spectra analysis indicated different trends in fluorescence background between the TPO and EVA laminates. The study also found that EVA had a higher increase in crystallinity and a lower increment rate in the carbonyl index and ether index compared to TPO. The UV-365 test for 18 days was sufficient to detect early discoloration and fluorophores generation in EVA. This method provides a quick assessment of the reliability of encapsulants, which is beneficial for the PV industry and encapsulant manufacturers.
POLYMER DEGRADATION AND STABILITY
(2022)
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
Chemistry, Physical
Shi-Yu Chen, Yu-Hang Song, Shuang Jiao, Chen Zou, Shi-Huan Li, Changle Chen, Xiao-Bing Lu, Ye Liu
Summary: Polyethylenes are widely used synthetic polymers, and introducing functional groups into polyethylene backbone can improve environmental persistence and compatibility with other materials. However, this process is hindered by the formation of alternating polyketones. By reducing the carbonyl density in polyketones, their properties become closer to polyethylene. In this study, Ni and Pd-coordinated cationic catalysts were used for nonalternating carbonylative copolymerization of ethylene, resulting in car-bonyl functionalized polyethylenes with similar properties to commercial high-density polyethylene.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Huijun Fan, Guanru Chang, Hui Wang, Shengyu Dai
Summary: Recently, researchers have successfully utilized the second coordination sphere effect to modulate the catalytic behavior of late-transition metal catalysts in olefin insertion polymerization. In this study, four bulky iminopyridyl nickel and palladium complexes with naphthalene or benzothiophene groups were prepared and investigated for their applications in olefin oligomerization. The as-prepared complexes showed good catalytic activity, producing hyperbranched oligomers with different microstructures. The benzothiophene-based Ni(ii)/Pd(ii) complexes generated significantly lower molecular weights of ethylene oligomers compared to the naphthalene-based complexes. The palladium complexes could also catalyze the co-oligomerization of ethylene and MA, resulting in hyperbranched co-oligomers with adjustable incorporation ratios of MA.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Polymer Science
Zhengpeng Yan, Guanru Chang, Wenping Zou, Gen Luo, Shengyu Dai
Summary: In this study, a series of benzocyclohexyl alpha-diimine Ni(ii) complexes were synthesized to obtain lightly branched and ultrahigh-molecular-weight polyethylenes. These complexes exhibited high activities in ethylene polymerization and resulted in polyethylenes with good mechanical properties.
Article
Chemistry, Physical
Zhou Lu, Xiaowei Xu, Yi Luo, Shengbao He, Weigang Fan, Shengyu Dai
Summary: In this study, α-diimine nickel complexes with bulky dibenzobarrelene backbone and bulky dibenzhydrylanilines were synthesized. These complexes exhibited high activity in ethylene polymerization and produced polyethylenes with very high molecular weights. Instead of highly branched polyethylenes, slightly branched semi-crystalline polyethylenes were obtained with these quasi-centrosymmetric nickel catalysts. The resulting polyethylenes had good mechanical properties and ethylene-methyl undecenoate copolymerization using these complexes yielded slightly branched high-molecular-weight polar functionalized copolymers.
Article
Polymer Science
Huayin Sun, Huijun Fan, Chuangao Zhu, Wenping Zou, Shengyu Dai
Summary: In this study, a series of partially chain-straightened propylene oligomers and functional propylene-methyl acrylate (P-MA) co-oligomers were synthesized using 8-alkyl-iminopyridyl Pd(II) catalysts. The molecular weight and polar monomer incorporation ratio could be controlled by using Pd(II) catalysts with different 8-alkyl-naphthyl substituents. The catalyst Pd1, without any substituent, showed the highest activity and generated oligomers with the lowest molecular weight. Additionally, Pd1 exhibited the best performance in propylene-MA copolymerization as it displayed the highest MA incorporation ratio.
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
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
Polymer Science
Hui Wang, Weiqing Lu, Huiqin Bi, Shengyu Dai
Summary: Introducing ortho-aryl dibenzosuberyl substituents into late-transition metal catalysts is an efficient way to retard chain transfer in olefin polymerization. In this study, it was found that dibenzosuberyl substituents can also suppress chain transfer and increase molecular weight in ethylene polymerization using bis(imino) pyridyl Fe(II) catalysts. A series of bis(imino) pyridyl ligands with unilateral diarylmethyl or dibenzosuberyl moiety were synthesized and characterized, and their corresponding Fe(II) catalysts exhibited high polymerization activity and generated high weight-average molecular weight polyethylenes with broad molecular weight distributions.
Article
Polymer Science
Wenbin Yuan, Weimin Li, Shengyu Dai
Summary: This study demonstrates the significant effect of the structural symmetry of alpha-diimine nickel catalysts on the microstructure of polyethylene. The plane-symmetric Ni(II) complexes used in ethylene polymerization showed high activities and yielded high molecular weight polyethylenes with tunable branching density. Compared to the centrosymmetric Ni(II) complex, the plane-symmetric Ni(II) complex produced significantly higher branched polyethylene. The resulting polyethylene materials from plane-symmetric Ni(II) complexes exhibited high strain, low stress at break values, and tunable recovery values, making them more elastomer-like compared to linear low-density polyethylene-like materials obtained from centrosymmetric Ni(II) complex.
Article
Materials Science, Multidisciplinary
Beihang Ding, Shengyu Dai
Summary: In this study, hyperbranched polar functionalized polyethylene was conveniently synthesized using the chain-walking polymerization (CWP) strategy. The ethylene chain walking polymerization catalyzed by Pd(II) complexes produced high molecular weight hyperbranched polyethylenes (HBPEs), and copolymerization of ethylene and methyl acrylate resulted in polar functionalized HBPEs with high density hydrophilic groups.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Polymer Science
Zhengpeng Yan, Wenping Zou, Shengyu Dai
Summary: A series of o-alkyl (Me, Et, iPr and tBu) pyridine-imine ligands with 2,4-bis(dibenzhydryl) substituents were synthesized and characterized. The corresponding Ni(ii) and Pd(ii) complexes were prepared and applied in polyethylene synthesis. Both Ni(ii) and Pd(ii) complexes showed different activities in ethylene polymerization and ethylene/MA copolymerization.
