Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

Ali, Amjad; Nadeem, Muhammad; Lü, Jie; Moradian, Jamile Mohammadi; Rasheed, Tahir; Aziz, T.; Maouche, Chanez; Guo, Yintian; Awais, Muhammad; Fan, Zhiqiang; Quo, Li

doi:10.1039/d1ra06243c

Cited by 15 publications

(26 citation statements)

References 47 publications

(72 reference statements)

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“…Following a quick examination of the reaction conditions, it was determined that the most effective results were achieved at 50 °C and an Al/Zr ratio of 800. Earlier research exposed that the catalyst rac -Me 2 Et(Ind) 2 ZrCl 2 with ethylene bridges had the highest ethylene homo- and E/P copolymerization activity [ 7 , 25 , 29 ]. TIBA immediately activated the rac -Me2Et(Ind)2ZrCl2/borate and the copolymerization occurred at considerable rates, providing strong ethylene/VCH copolymerization activity in the beginning.…”

Section: Resultsmentioning

confidence: 99%

“…Cyclic dienes (e.g., norbornane N.B), dicyclopentadiene (DCPD), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), and 4-vinylcyclohexene (VCH) can be prepared by a reaction in multiple fundamentally different ways, relying upon the weather already bound by vinyl addition reactions, radical and cationic polymerization, and ring-opening metathesis olefin polymerization [ 1 , 2 , 3 , 4 ]. Compared to cyclic dienes synthesized by radical or cationic and ring-opening polymerization, vinyl addition cyclic dienes exhibit excellent thermal stability, low dielectric constant, and higher glass-transition temperature, all of which are a result of the double bond cyclic backbone chain structure [ 5 , 6 , 7 ]. Co- and terpolymers of ethylene/propylene (EPM) and ethylene/propylene/diene (EPDM) are significant manufacturing thermoplastics [ 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…This has been demonstrated in previous studies [ 26 , 29 ]. Catalyst inactivity or dormancy, death, and other improbable outcomes are possible extra phases [ 7 , 25 ]. It is currently difficult for researchers to quickly determine the kinetics of polymerization for many different catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Methods for Predicting Ethylene/Cyclic Olefin Copolymerization Rates Promoted by Single-Site Metallocene: Kinetics Is the Key

et al. 2022

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In toluene at 50 °C, the vinyl addition polymerization of 4-vinyl-cyclohexene (VCH) comonomers with ethylene is investigated using symmetrical metallocene (rac-Et(Ind)2ZrCl2) combined with borate/TIBA. To demonstrate the polymerizations’ living character, cyclic VCH with linear-exocyclicπ and endocyclicπ bonds produces monomodal polymers, but the dispersity (Ɖ) was broader. The copolymers obtained can be dissolved in conventional organic solvent and have excellent thermal stability and crystalline temperature (ΔHm), and their melting temperature (Tm) varies from 109 to 126 °C, and ΔHm ranges from 80 to 128 (J/g). Secondly, the distribution of polymeric catalysts engaged in polymer chain synthesis and the nature of the dormant state are two of the most essential yet fundamentally unknown aspects. Comprehensive and exhaustive kinetics of E/VCH have shown numerous different kinetic aspects that are interpreted as manifestations of polymeric catalysts or of the instability of several types of active center [Zr]/[C*] fluctuations and formation rates of chain propagation RpE, RpVCH, and propagation rate constants kpE and kpVCH, the quantitative relationship between RpE, RpVCH and kpE, kpVCH and catalyst structures, their constituent polymer Mw, and their reactivity response to the endocyclic and exocyclic bonds of VCH. The kinetic parameters RpE, RpVCH, kpE, and kpVCH, which are the apparent rates for the metallocene-catalyzed E/VCH, RpE, and kpE values, are much more significant than RpVCH and kpVCH at 120 s, RpE and RpVCH 39.63 and 0.78, and the kpE and kpVCH values are 6461 and 93 L/mol·s, respectively, and minor diffusion barriers are recommended in the early stages. Compared with previously reported PE, RpE and kpE values are 34.2 and 7080 L/mol·s. VCH increases the RpE in the initial stage, as we are expecting; this means that the exocyclic bond of VCH is more active at the initial level, and that the chain transfer reaction of cyclic internal π double is increased with the reaction time. The tp versus Rp, kp, and [Zr]/[C*] fraction count may be fitted to a model that invokes deactivation of growing polymer chains. At tp 120–360 s higher, the incorporation rate of VCH suppresses E insertion, resulting in reduced molecular weight.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Methods for Predicting Ethylene/Cyclic Olefin Copolymerization Rates Promoted by Single-Site Metallocene: Kinetics Is the Key

et al. 2022

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“…Lotte Chemical In the vast majority of publications, MAO (or modified MAO) and perfluoroaryl borates are reported to be used to activate metallocene precatalysts in the synthesis of polyolefins [13,14,[21][22][23], including EPDM [4,[15][16][17][18][19][24][25][26]. However, MAO is too expensive, unstable during storage, and is used in large molar excess to the precatalyst.…”

Section: Metallocene Catalystsmentioning

confidence: 99%

Homogeneous Group IVB Catalysts of New Generations for Synthesis of Ethylene-Propylene-Diene Rubbers: A Mini-Review

et al. 2022

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Ethylene-propylene-diene rubbers (EPDM) are one of the most important polyolefin materials widely commercialized and used in various industries in recent years. The production of EPDM is based solely on catalytic coordination polymerization processes. The development of new catalysts and processes for the synthesis of EPDM has expanded the range of products and their manufacturing in terms of energy efficiency, processability, and environmental safety. This mini-review mainly analyzes patented data on the synthesis of EPDM on new-generation single-site catalytic systems based on Group IVB complexes including the systems commercialized by major manufacturers of EPDM. The advantages of these systems are evident in comparison with conventional vanadium systems introduced into production in the 1960s and used to date in the industrial synthesis of EPDM.

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“…The native CNCs lost their hydrophilicity after modification with epoxy. The modified CNCs showed hydrophobic behavior (CA 105 ± 2 °) (Ali et al, 2021;Zhang et al, 2021).…”

Section: The Contact Angle Of Cncs With E-51 Epoxy Systemmentioning

confidence: 99%

Modification of Cellulose Nanocrystals With 2-Carboxyethyl Acrylate in the Presence of Epoxy Resin for Enhancing its Adhesive Properties

Ali

Aziz

Zheng

et al. 2022

Front. Bioeng. Biotechnol.

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Cellulose nanocrystals (CNCs) have unparalleled advantages in the preparation of nanocomposites for various applications. However, a major challenge associated with CNCs in nanocomposite preparation is the lack of compatibility with hydrophobic polymers. The hydrophobic modification of CNCs has attracted increasing interest in the modern era standing with long challenges and being environmentally friendly. Here, we synthesized CNCs by using cotton as raw material and then modified them with 2-carboxyethyl acrylate to improve their corresponding mechanical, adhesive, contact angle, and thermal properties. Different concentrations (1–5 wt%) of CNCs were used as modifiers to improve the interfacial adhesion between the reinforced CNCs and E-51 (Bisphenol A diglycidyl ether) epoxy resin system. CNCs offered a better modulus of elasticity, a lower coefficient of energy, and thermal expansion. Compared with the standard sample, the modified CNCs (MCNCs) showed high shear stress, high toughness, efficient degradation, thermal stability, and recycling due to the combined effect of the hyperbranched topological structure of epoxy with good compatibility. The native CNCs lost their hydrophilicity after modification with epoxy, and MCNCs showed good hydrophobic behavior (CA = 105 ± 2°). The findings of this study indicate that modification of CNCs with 2-carboxyethyl acrylate in the presence of epoxy resin and the enhancement of the features would further expand their applications to different sectors.

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Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

Abstract: The kinetics and mechanism of ethylene and 5-ethylidene-2-norbornene copolymerization catalyzed by rac-Et(Ind)2ZrCl2 were investigated using 2-thiophenecarbonyl chloride.

Cited by 15 publications

References 47 publications

Methods for Predicting Ethylene/Cyclic Olefin Copolymerization Rates Promoted by Single-Site Metallocene: Kinetics Is the Key

Methods for Predicting Ethylene/Cyclic Olefin Copolymerization Rates Promoted by Single-Site Metallocene: Kinetics Is the Key

Homogeneous Group IVB Catalysts of New Generations for Synthesis of Ethylene-Propylene-Diene Rubbers: A Mini-Review

Modification of Cellulose Nanocrystals With 2-Carboxyethyl Acrylate in the Presence of Epoxy Resin for Enhancing its Adhesive Properties

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