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Ali A, Naveed A, Maroń A, Younis MA, Moradian JM, Yousaf B, Aziz T, Ali RN, Ahmad N, Alomar SY, Zheqiang F, Guo L. Copolymerization of ethylene and isoprene via silicon bridge metallocene [rac-Me 2Si(2-Me-4-Ph-Ind) 2ZrCl 2] catalyst: A new way to control the composition and microstructure of copolymers. CHEMOSPHERE 2024; 347:140700. [PMID: 37977533 DOI: 10.1016/j.chemosphere.2023.140700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/03/2023] [Accepted: 11/10/2023] [Indexed: 11/19/2023]
Abstract
The copolymerization of ethylene (E) with isoprene (Ip) was performed catalyzed by a symmetrical catalyst exhibiting a silicon bridge [rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2 with the combination of borate/TIBA activator. The effect of cocatalyst, Ip concentration, and polymerization temperature on the activity, molecular weight (Mw), distribution (MWD), comonomer composition, chain structure (regio- and stereoselectivity), and resulting side reactions were logically addressed. Gel-permeation chromatography (GPC) was used to characterize the Mw and polydispersity, while nuclear magnetic resonance (NMR) was employed for the chain structure of the polymers. The catalytic activity was significantly lower by increasing the Ip concentration in the feed, and the isoprene content in resulting polymers was lower under the reaction condition, leading to higher activity. Insertion of isoprene units in polymer structure demonstrates the higher regioselectivity for the 3,4 connections than the 1,4 connections and is expected to be a high-resistance polymer against acids. The MWD presented monomodal even with a higher concentration (1.44 mol/L) and did not appear as low Mw peaks of Ip. The Mw was higher with a broader MWD when purely TIBA was used as a cocatalyst, and it significantly reduced and presented a narrowed MWD with TEA in the cocatalyst. The higher efficiency of the catalyst for the higher insertion of Ip (C=C double bond) effectively modifies the polymer backbone. It is expected to be a promising candidate for easily degradable and favorable solutions for solving environmental problems caused by PE. wastes.
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Affiliation(s)
- Amjad Ali
- School of Materials Science & Engineering, Jiangsu University, Zhenjiang, 212013, PR China; Institute of Chemistry, University of Silesia, Szkolna 9, Katowice, 40-600, Poland; MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, PR China
| | - Ahmad Naveed
- School of Materials Science & Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Anna Maroń
- Institute of Chemistry, University of Silesia, Szkolna 9, Katowice, 40-600, Poland
| | - Muhammad Adnan Younis
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, PR China
| | | | - Balal Yousaf
- Department of Technologies and Installations for West Management, Faculty of Engineering, Silesian University of Technology, Konarskiego 18, 44-100, Gliwice, Poland
| | - Tariq Aziz
- School of Engineering Yunqi Campus, Westlake University, Hangzhou, Zhejiang, 310024, PR China
| | - Rai Nauman Ali
- Laboratory of Inorganic Materials for Sustainable Energy Technologies, Mohammed IV Polytechnic University, Benguirer, Morocco
| | - Naushad Ahmad
- Department of Chemistry, College of Science, King Saud University, Riyadh, 11451, Kingdom of Saudi Arabia
| | - Suliman Yousef Alomar
- Zoology Department, College of Science, King Saud University, Riyadh, 11451, Kingdom of Saudi Arabia
| | - Fan Zheqiang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, PR China
| | - Li Guo
- School of Materials Science & Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
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Ali A, Alabbosh KFS, Naveed A, Uddin A, Chen Y, Aziz T, Moradian JM, Imran M, Yin L, Hassan M, Qureshi WA, Ullah MW, Fan Z, Guo L. Evaluation of the Dielectric and Insulating Properties of Newly Synthesized Ethylene/1-Hexene/4-Vinylcyclohexene Terpolymers. ACS OMEGA 2022; 7:31509-31519. [PMID: 36092561 PMCID: PMC9453979 DOI: 10.1021/acsomega.2c04123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Terpolymerizations of newly synthesized ethylene (E), vinylcyclohexene (VCH), and 1-hexene were carried out with symmetrical metallocene catalysts rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2 (catalyst A) and rac-Et(Ind)2ZrCl2 (catalyst B). X-ray diffractometry (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), high-temperature gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) spectroscopy were used to evaluate the behavior and microstructure of the polymers. The activity of catalyst B was 1.49 × 106 gm/mmolMt·h), with a T m of 73.45 (°C) and ΔH m of 43.19 (J/g), while catalyst A produced first higher 1-hexene, 19.6 mol %, and VCH contents with a narrow molecular weight distribution (MWD). In previous reports, ethylene propylene monomer dienes (EPDM) had a low content and were used for dielectric and insulating properties with nanomaterials. Second, this paper presents a kind of elastomeric polymers based on E/1-hexene and VCH with a high dielectric constant (k = 6-4) and mechanical properties. In addition, low dielectric loss suggests the suitable application potential of these polymeric materials for the fabrications of capacitors. Also, this work reveals that these polymers can be a better candidate for high-voltage electrical insulation due to their enhanced dielectric, mechanical, and thermal characteristics. To examine the insulating property, the interface characteristics of the polymer were evaluated using electrochemical impedance spectroscopy (EIS) with a frequency range of 1 × 105-0.01 Hz and an amplitude of 5.0 mV. EIS is an effective method to investigate the polymers' interfacial electron transfer characteristics. The EIS Nyquist plot showed high Warburg impedance features in the low-frequency domain with straight lines without a semicircle, suggesting that the property of the polymer owing to the high electrical resistance and poor conductivity for ionic kinetics in the electrolyte may have surpassed that of the semicircle. Although the slope of low frequencies in polymers holding potent exoelectrogenic bacteria (Shewanella oneidensis MR-1) as a charge carrier in the electrolyte could significantly reduce the Warburg resistance, it still could not improve the conductivity, which demonstrated that the external charge supply could not alter the insulating property in the used polymers.
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Affiliation(s)
- Amjad Ali
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | | | - Ahmad Naveed
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Azim Uddin
- Institute for Composites Science Innovation (InCSI), School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China
| | - Yanlin Chen
- Institute for Composites Science Innovation (InCSI), School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China
| | - Tariq Aziz
- School of Engineering Yunqi Campus, Westlake University, Hangzhou, Zhejiang 310024, P. R. China
| | | | - Muhammad Imran
- Department of Chemistry, Government College University, Lahore 54000, Pakistan
| | - Lu Yin
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Mobashar Hassan
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Waqar Ahamad Qureshi
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Muhammad Wajid Ullah
- Biofuels Institute, School of Environment, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Zhiqiang Fan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Li Guo
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
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Ali A, Moradian JM, Naveed A, Aziz T, Muhammad N, Maouche C, Guo Y, Yaseen W, Yassen M, Haq F, Hassan M, Fan Z, Guo L. Progress toward Polymerization Reaction Monitoring with Different Dienes: How Small Amounts of Dienes Affect ansa-Zirconocenes/Borate/Triisobutylaluminium Catalyst Systems. Polymers (Basel) 2022; 14:polym14163239. [PMID: 36015497 PMCID: PMC9414859 DOI: 10.3390/polym14163239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022] Open
Abstract
The objectives of this work were to address the fundamental characteristics of ansa-zirconocene catalyzed E/diene copolymerization and E/diene/1-hexene and E/diene/propylene terpolymerizations, and the quantitative relationship between diene structure and polymer chain propagation rate constant in term of quantifiable catalytic active sites. One of the most important but unknown factors in olefins ansa-zirconocene complexes is the distribution of the catalyst between sites actively participating in polymer chain formation and dormant sites. A set of ethylene/dienes copolymerizations, and ethylene/dienes/1-hexene and ethylene/dienes/1-hexene terpolymerizations catalyzed with ansa-zirconocenes/borate/triisobutylaluminium (rac-Et(Ind)2ZrCl2/[Ph3C][B(C6F5)4]/triisobutylaluminium (TIBA) were performed in toluene at 50 °C To determine the active center [C*]/[Zr] ratio variation in the copolymerization of E with different dienes and their terpolymerization with 1-hexene and propylene, each polymer propagation chain ends were quenched with 2-thiophenecarbonyl, which selectively quenches the metal–polymer bonds through acyl chloride. The ethylene, propylene, 1-hexene, and diene composition-based propagation rate constants (kpE, kpP, kp1-H, and kpdiene), thermal (melting and crystalline) properties, composition (mol% of ethylene, propylene, 1-hexene, and diene), molecular weight, and polydispersity were also studied in this work. Systematic comparisons of the proportion of catalytically [Zr]/[C*] active sites and polymerization rate constant (kp) for ansa-zirconocenes catalyzed E/diene, E/diene/1-hexene, and E/diene/propylene polymerization have not been reported before. We evaluated the addition of 1-hexene and propylene as termonomers in the copolymerization with E/diene. To make a comparison for each diene under identical conditions, we started the polymerization by introducing an 80/20 mole ratio of E/P and 0.12 mol/L of 1-hexene in the system. The catalyst behavior against different dienes, 1-hexene, and propylene is very interesting, including changes in thermal properties, cyclization of 1-hexene, and decreased incorporation of isoprene and butadiene, changes in the diffusion barriers in the system, and its effect on kp.
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Affiliation(s)
- Amjad Ali
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Jamile Mohammadi Moradian
- Biofuels Institute, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Ahmad Naveed
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China
- Correspondence: (A.N.); (L.G.)
| | - Tariq Aziz
- School of Engineering Yunqi Campus, Westlake University, Hangzhou 310024, China
| | - Nadeem Muhammad
- Department of Environmental Engineering, Wuhang University of Technology, Wuhan 430223, China
| | - Chanez Maouche
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yintian Guo
- Zhejiang Hetian Chemical Co., Ltd., Hangzhou 310023, China
| | - Waleed Yaseen
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Maria Yassen
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Fazal Haq
- Department of Chemistry, Gomal University, Khyber Pakhtunkhwa 29220, Pakistan
| | - Mobashar Hassan
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Zheqing Fan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Li Guo
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University, Zhenjiang 212013, China
- Correspondence: (A.N.); (L.G.)
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Ali A, Naveed A, Shehzad K, Aziz T, Rasheed T, Moradian JM, Hassan M, Rahman A, Zhiqiang F, Guo L. Polymerization kinetics of bicyclic olefins and mechanism with symmetrical ansa-metallocene catalysts associated with active center count: relationship between their activities and structure and activation path. RSC Adv 2022; 12:15284-15295. [PMID: 35693231 PMCID: PMC9118019 DOI: 10.1039/d2ra01264b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/02/2022] [Indexed: 12/30/2022] Open
Abstract
Copolymerization of ethylene (E) with 5-vinyl-2-norbornene (VNB) catalyzed by ansa-metallocenes allows the precise control of essential polymeric properties such as comonomer incorporation, molecular weight (Mw), and polydispersity (Đ). Significant efforts have been devoted to synthesizing and developing novel catalysts, cocatalysts, and activators, although the fundamental elements of catalytic processes remain unclear. For example, it is questionable how polymeric catalysts are divided across dormant and active sites and how this distribution affects the order of monomers for the propagation rate, which widely vary in the literature. Furthermore, although the empirical correlation between the monomers and average Mw has been established in many systems, the fundamental processes of chain termination remain unknown. Furthermore, the involvement of ion-pairing in metallocene-catalyzed polymerization and the termination mechanisms are also contentious issues. In this study, we describe the use of a quenched-labeling technique based on acyl chloride to selectively quench the zirconium metal–polymeric bond, which can be used to study the kinetics, active site [Zr][C*] counting, copolymer microstructure, and molecular weight distribution (MWD) to determine the rate laws for chain initiation, chain propagation rate (Rp), propagation rate constant (kp) and chain termination. In addition, we also predict previously unknown chemical characteristics of E/bicyclic copolymerization processes, where either a cis-endocyclic double bond with steric properties or a vinyl exocyclic double bond affects the activity, i.e., [Zr]/[*C], (Rp) and (kp). All these properties require the implementation of a particular kinetic mechanism that assumes the low activity of the building copolymer chains incorporating a single ethylene/VNB unit, i.e., the Cp2Zr–C2H5 group, in the ethylene addition process in the Cp2Zr–C bond. Due to β-agostic stabilization, the Cp2Zr–C2H5 group exhibits a distinct feature. These effects were confirmed experimentally, such as the E/VNB co-polymer activity and VNB mol%, propagation rate decrease in the polymerization time (tp) of 120 s to 1800 s, crystalline properties, and significant increase in molecular weight. The active center [Zr]/[*C] fraction considerably increased in the initial (tp) 840 s, and subsequently tended to the steady stage of 33%, which is lower than previously reported E homo- and E/P copolymerization. The lower [C*]/[Zr] in both the early and stable stages, decrease in VNB mol%, and Rp with tp can be associated with the more significant fraction of Cp2Zr–CH2CH3-type dormant site by the β-agostic hydrogen interaction with the Cp2Zr metal. The tpversus RpE, RpVNB, kpE, kpVNB, and [Zr]/[C*] count could be fitted to a model that invokes deactivation of the growing polymer chains. In the case of the thermal behavior of the copolymers (melting temperature (Tm) and crystalline temperature (ΔHm)), Tm varied from 101 °C to 121 °C, while ΔHm varied from 9 to 16 (J g−1). Copolymerization of ethylene (E) with 5-vinyl-2-norbornene (VNB) catalyzed by ansa-metallocenes allows the precise control of essential polymeric properties such as comonomer incorporation, molecular weight (Mw), and polydispersity (Đ).![]()
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Affiliation(s)
- Amjad Ali
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University Zhenjiang 212013 P. R. China .,MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University Hangzhou 310027 P. R. China
| | - Ahmad Naveed
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University Zhenjiang 212013 P. R. China
| | - Khurram Shehzad
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Center (HIC), Zhejiang University Xiaoshan 311200 China .,State Key Laboratory of Silicon Materials, Zhejiang University Hangzhou 310027 China.,ZJU-UIUC Joint Institute, Zhejiang University Jiaxing 314400 China
| | - Tariq Aziz
- Westlake University, School of Engineering Yunqi Campus Hangzhou Zhejiang 310024 PR China
| | - Tahir Rasheed
- Interdisciplinary Research Center for Advanced Materials, King Fahd University of Petroleum and Minerals (KFUPM) Dhahran 31261 Saudi Arabia
| | | | - Mobashar Hassan
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University Zhenjiang 212013 P. R. China
| | - Abdul Rahman
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Center (HIC), Zhejiang University Xiaoshan 311200 China .,Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University Hangzhou 310027 China
| | - Fan Zhiqiang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University Hangzhou 310027 P. R. China
| | - Li Guo
- Research School of Polymeric Materials, School of Materials Science & Engineering, Jiangsu University Zhenjiang 212013 P. R. China
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