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TiCl4/MgCl2/MCM-41 Bi-Supported Ziegler–Natta Catalyst: Effects of Catalyst Composition on Ethylene/1-Hexene Copolymerization. Catalysts 2021. [DOI: 10.3390/catal11121535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
TiCl4/MgCl2/MCM-41 type bi-supported Ziegler-Natta catalysts with different MgCl2/MCM-41 ratios were synthesized by adsorbing TiCl4 onto MgCl2 crystallites anchored in mesopores of MCM-41 (mesoporous silica with 3.4 nm pore size). Ethylene/1-hexene copolymerization with the catalysts was conducted at different 1-hexene concentrations and ethylene pressures. MgCl2/MCM-41 composite supports and the catalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption analysis (BET), and elemental analysis. The copolymers were fractionated by extraction with boiling n-heptane, and comonomer contents of the fractions were determined. Under 4 bar ethylene pressure, the bi-supported catalysts showed higher activity and a stronger comonomer activation effect than the TiCl4/MgCl2 catalyst. In comparison with the TiCl4/MgCl2 catalyst, the bi-supported catalysts produced much less copolymer fraction of low molecular weight and high 1-hexene content, meaning that the active center distribution of the catalyst was significantly changed by introducing MCM-41 in the support. The copolymer produced by the bi-supported catalysts showed similar melting temperature to that produced by TiCl4/MgCl2 under the same polymerization conditions. The space confinement effect of the mesopores of MCM-41 on the size and structure of MgCl2 crystallites is proposed as the main reason for the special active center distribution of the bi-supported catalysts.
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Chen Y, Wan M, Zhong Y, Gao T, Zhang Y, Yan F, Huang D, Wu Y, Weng Z. Partially Hydrolyzed Guar Gum Modulates Gut Microbiota, Regulates the Levels of Neurotransmitters, and Prevents CUMS-Induced Depressive-Like Behavior in Mice. Mol Nutr Food Res 2021; 65:e2100146. [PMID: 34125489 DOI: 10.1002/mnfr.202100146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/29/2021] [Indexed: 12/20/2022]
Abstract
SCOPE Depression is the leading cause of disability around the world; however, most antidepressants have drug tolerance and serious side effects. In this study, it is explored whether partially hydrolyzed guar gum (PHGG) is a safe food that exhibits protection in a mouse model of depression. METHODS AND RESULTS PHGG is orally administered to mice with depression induced by chronic unpredictable mild stress (CUMS) in two animal experiments (prevention trial and intervention trial) to characterize the potentially protective effect of PHGG. The results in the prevention trial show that PHGG significantly inhibits the loss of body weight, and prevents CUMS-induced depressive-like behavior in mice. The beneficial effects may be associated with PHGG modulating the gut microbiota structure and then increasing the levels of short-chain fatty acids in mice feces and the levels of 5-hydroxytryptamine and dopamine in serum, striatum, and hippocampus. Besides, PHGG in the intervention trial is less effective than that in the prevention trial, but it may have a synergistic effect on improving depression with fluoxetine. CONCLUSIONS This study suggests that moderate daily intake of PHGG can contribute to relieving depressive-like behavior.
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Affiliation(s)
- Yanqiu Chen
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Mei Wan
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China.,Department of Dermatology, The First Affiliated Hospital of the Army Medical University, Chongqing, 400038, China
| | - Yi Zhong
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Tingfang Gao
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Yuehan Zhang
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Fen Yan
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Da Huang
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Yuanzi Wu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Zuquan Weng
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, 350108, China
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Akram MA, Liu X, Jiang B, Zhang B, Ali A, Fu Z, Fan Z. Effect of alkylaluminum cocatalyst on ethylene/1-hexene copolymerization and active center distribution of MgCl2-supported Ziegler-Natta catalyst. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2021. [DOI: 10.1080/10601325.2021.1892495] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Muhammad Adnan Akram
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Xiaoyu Liu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Baiyu Jiang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Biao Zhang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Amjad Ali
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Zhisheng Fu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Zhiqiang Fan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
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Progress in MgCl2 supported Ziegler-Natta catalyzed polyolefin products and applications. JOURNAL OF POLYMER RESEARCH 2021. [DOI: 10.1007/s10965-021-02412-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Preparation of PP/2D-Nanosheet Composites Using MoS2/MgCl2- and BN/MgCl2-Bisupported Ziegler–Natta Catalysts. Catalysts 2020. [DOI: 10.3390/catal10060596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Polypropylene/molybdenum disulfied (PP/MoS2) and Polypropylene/hexagonal boron nitride (PP/hBN) nanocomposites with varying concentration (0–6 wt %) were fabricated via in situ polymerization using two-dimensional (2D)-nanosheet/MgCl2-supported Ti-based Ziegler–Natta catalysts, which was prepared through a novel coagglomeration method. For catalyst preparation and interfacial interaction, MoS2 and hBN were modified with octadecylamine (ODA) and octyltriethoxysilane (OTES), respectively. Compared with those of pristine PP, thermal stability of composites was 70 °C higher and also tensile strength and Young’s modulus of the composites were up to 35% and 60% higher (even at small filler contents), respectively. The alkyl-modified 2D nanofillers were characterized by strong interfacial interactions between the nanofiller and the polymer matrix. The coagglomeration method employed in this work allows easy introduction and content manipulation of various 2D-nanosheets for the preparation of 2D-nanosheet/MgCl2-supported Ti-based Ziegler–Natta catalysts.
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