Article
Polymer Science
Shuyuan Yu, Chenggen Zhang, Fei Wang, Xinru Liang, Mengyao Yang, Mengyu An
Summary: Density functional theory (DFT) was used to investigate the promotion of B(C6F5)(3) as a ligand for titanium (or vanadium) catalysts in ethylene/1-hexene copolymerization reactions. The results showed that ethylene insertion into Ti-B (with B(C6F5)(3) as a ligand) was preferred over Ti-H, both thermodynamically and kinetically. In addition, V-B (with B(C6F5)(3) as a ligand) was found to be preferred over V-H for the entire ethylene/1-hexene copolymerization reaction, with higher reaction activity observed for V-B compared to Ti-B.
Article
Biochemistry & Molecular Biology
Ildar I. Salakhov, Tatiana B. Mikenas, Vladimir A. Zakharov, Valeriy G. Kozlov, Mikhail A. Matsko, Tatiana N. Suslova
Summary: This study investigates the catalytic performance of a titanium-magnesium catalyst in ethylene homopolymerization and ethylene/1-hexene copolymerization in the presence of chlorocyclohexane and hexachloro-p-xylene. The modified catalyst shows significantly increased activity, and the kinetic parameters and copolymer composition were determined.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Multidisciplinary
Amjad Ali, Muhammad Nadeem, Jinwei Lu, Jamile Mohammadi Moradian, Tahir Rasheed, Tariq Aziz, Chanez Maouche, Yintian Guo, Muhammad Awais, Fan Zhiqiang, Li Quo
Summary: The kinetics and mechanism of ethylene and cyclic diene copolymerization catalyzed by a specific catalyst were studied using a quench-labeling method, and the products were characterized to understand the behavior of the metallocene catalyst and address mechanistic issues. The study involved a quantitative approach of catalyst speciation, stereodynamics, and micro-kinetics, providing insights into elastomeric synthesis, catalyst resting state nature, and ion-pairing during polymerization.
Article
Chemistry, Inorganic & Nuclear
Amjad Ali, Azim Uddin, Muhammad Imran Jamil, Xiran Shen, Mudassar Abbas, Tariq Aziz, Munir Hussain, Shahid Hussain, Rui Fang, Zhiqiang Fan, Li Guo
Summary: The copolymerization of ethylene-propylene (E-P) using asymmetric metallocene catalysts under similar conditions was studied, showing significant effects of polymerization time on sulfur content and reactivity ratio constants. The use of different catalysts also influenced the active center levels in the E/P copolymers, with a notable decline in chain propagation rate constants over time.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Xu-ling Wang, Yan-ping Zhang, Fei Wang, Li Pan, Bin Wang, Yue-sheng Li
Summary: A series of methyl nickel complexes with phosphino-naphtholate chelate ligands have been designed and synthesized with high activity towards ethylene polymerization and ethylene/unsaturated acid ester copolymerization. These catalysts show outstanding catalytic activities, achieving high productivity in both ethylene polymerization and ethylene/methyl acrylate copolymerization.
Article
Polymer Science
Vladislav A. Tuskaev, Svetlana Ch Gagieva, Dmitry A. Kurmaev, Sergey Zubkevich, Ivan Fedyanin, Mikhail Buzin, Galina G. Nikiforova, Viktor G. Vasil'ev, Daniele Saracheno, Viktor Privalov, Boris M. Bulychev
Summary: The copolymerization of ethylene and 1-hexene was conducted using a new Ti (IV) complex stabilized by fluorinated 2-hydroxymethylphenol derivatives. The copolymers were characterized by DSC, GPC, and (13)C NMR, and the effects of ligand structure and organoaluminum activator on various properties were investigated. The complex with adamantyl substituent showed the highest activity and achieved the highest 1-hexene incorporation content of 18.9 mol%.
Article
Chemistry, Multidisciplinary
Clement G. Collins Rice, Jean-Charles Buffet, Zoe R. Turner, Dermot O'Hare
Summary: Novel permethylindenyl-phenoxide (PHENI*) ansa-metallocene titanium complexes immobilized on solid supports show high catalytic activity for slurry-phase ethylene polymerization, producing substantially disentangled polyethylene with a weight-average molecular weight of 3.4 MDa.
CHEMICAL COMMUNICATIONS
(2021)
Article
Engineering, Chemical
Shaomeng Zhang, Chunpeng Cao, Wensi Guo, Yuan Zhang, Min Sun, Wei Yang, Lei He, Qigu Huang
Summary: By improving the mononuclear [Me2Si(C5H4)(2)]TiCl2 catalyst, a binuclear Ti olefin polymerization catalyst, complex 1,4-phenoxy{[Me2Si(C5H4)(2)]TiCl}(2) (Complex 2) was synthesized. Complex 2 showed superior thermal stability and higher activity for ethylene polymerization due to the addition of the phenoxy group, which provided a denser coordination environment and increased the molecular weight of the polymer.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Chemistry, Multidisciplinary
Amjad Ali, Khulood Fahad Saud Alabbosh, Ahmad Naveed, Azim Uddin, Yanlin Chen, Tariq Aziz, Jamile Mohammadi Moradian, Muhammad Imran, Lu Yin, Mobashar Hassan, Waqar Ahamad Qureshi, Muhammad Wajid Ullah, Zhiqiang Fan, Li Guo
Summary: In this study, terpolymerizations of newly synthesized ethylene, vinylcyclohexene, and 1-hexene were conducted using different symmetrical metallocene catalysts. The behavior and microstructure of the resulting polymers were evaluated using various analytical techniques. The findings suggest that these polymers exhibit high dielectric constant and mechanical properties, making them potential candidates for high-voltage electrical insulation.
Article
Chemistry, Inorganic & Nuclear
Suting Xu, Yanchen Huo, Xiang Hu, Fei Wang, Li Pan, Xiaochao Shi
Summary: In this study, rare-earth metal complexes bearing tetrahydrofluorenyl ligands were synthesized and characterized. These complexes showed excellent catalytic activity for the polymerization of styrene and butadiene, resulting in diblock copolymers with highly syndiotactic polystyrene block and a 1,4-specific PBD block. The study also revealed the significant difference in reactivity ratios between butadiene and styrene, supporting the block structure of the copolymers. Morphology and mechanical properties of the selected diblock copolymer were investigated.
INORGANIC CHEMISTRY
(2023)
Article
Polymer Science
Zhen Zhang, Yang Jiang, Kai Zhang, Zhong-Yi Cai, Shi-Hui Li, Dong-Mei Cui
Summary: The catalytic performance of rare-earth metal dialkyl complexes in combination with DMAO for styrene polymerization was investigated, with certain complexes showing high catalytic activity and selectivity. Moreover, the system was found to be effective for the polymerization of other styrene derivatives and the copolymerization of ethylene and styrene.
CHINESE JOURNAL OF POLYMER SCIENCE
(2021)
Article
Polymer Science
Amjad Ali, Ahmad Naveed, Tahir Rasheed, Tariq Aziz, Muhammad Imran, Ze-Kun Zhang, Muhammad Wajid Ullah, Ameer Ali Kubar, Aziz Ur Rehman, Zhiqiang Fan, Li Guo
Summary: The vinyl addition polymerization of 4-vinyl-cyclohexene (VCH) comonomers with ethylene in toluene at 50 degrees C was investigated using symmetrical metallocene catalyst combined with borate/TIBA. The obtained copolymers exhibited good solubility in conventional organic solvents, excellent thermal stability, and crystalline properties.
Article
Polymer Science
Maryam Masoori, Reza Rashedi, Abdolhannan Sepahi, Mohammad Hossein Jandaghian, Ehsan Nikzinat, Saeed Houshmandmoayed
Summary: This study investigates the relationship between catalyst characteristics and polymerization conditions with catalyst behavior and polymer properties in the ethylene/alpha-olefin (co)polymerization using Ziegler-Natta catalyst. The results demonstrate that the characteristics of the catalyst and the presence of comonomers significantly impact the catalyst behavior and product properties.
JOURNAL OF POLYMER RESEARCH
(2022)
Article
Multidisciplinary Sciences
Chen Zou, Guifu Si, Changle Chen
Summary: The authors present an ionic anchoring support strategy that allows the heterogenization of homogeneous metal complexes on solid supports. This strategy is highly versatile and enables strong catalyst-support interactions while tolerating various polar functional groups. The supported catalysts showed improved polymerization properties and higher comonomer incorporation compared to their unsupported counterparts.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
S. Olivia Gunther, Qingheng Lai, Todd Senecal, Rafael Huacuja, Sean Bremer, David M. Pearson, Jessica C. DeMott, Nattamai Bhuvanesh, Oleg Ozerov, Jerzy Klosin
Summary: By preparing and evaluating various carborane salts as activators, it was found that activators based on undecachloro carboranes led to highly active catalysts, while other activators were inactive under specific conditions. Polymer samples obtained from different catalysts showed similar performance, indicating that carborane anions do not influence catalyst kinetics.
Article
Engineering, Chemical
Yi Zhou, Arash Alizadeh, Boping Liu, Joao B. P. Soares
Summary: The framework proposed in this study is based on the Monte Carlo/random-pore polymeric flow model for simulating industrial polymerizations in both single-particle and continuous slurry reactor systems. It can accurately describe the effects of various catalyst characteristics on polymer yield and microstructure. By combining Monte Carlo simulation with single-particle models, these simulations demonstrate the versatility and thoroughness in analyzing and predicting the behavior of commercial polyolefin reactors.
MACROMOLECULAR REACTION ENGINEERING
(2021)
Article
Engineering, Chemical
Saeid Atashrouz, Mohammad Rahmani, Bahram Nasernejad, Joao B. P. Soares
Summary: The study focused on developing an industrial ethylene polymerization FBR model operating in condensed mode, comparing a simple two-phase model with a more complex one that considers the presence of a wet zone. Results showed that the complex model (model II) was more accurate in predicting production rate and catalyst flow rate. Additionally, it was found that two zones, wet and dry, are formed in the condensed-mode operation of FBRs.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Nanoscience & Nanotechnology
Gayathri Kalyanaraman, Zahra Rostami Najafabadi, Joao Soares, Milana Trifkovic
Summary: The research highlights that increasing the graft density of partially hydrophobic grafted polymers can improve dispersion, initial dewatering rate, and viscoelastic response of flocculants, while having minimal impact on long-term dewatering properties. Three-dimensional microscopic images reveal that higher graft density leads to more trapped water within flocs, resulting in slower post-flocculation dewatering rate.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Engineering, Chemical
Saeid Mehdiabadi, Olivier Lhost, Aurelien Vantomme, Joao B. P. Soares
Summary: The microstructure of polyolefins made with a metallocene supported on a porous carrier is generally less homogeneous, with broader molecular weight and chemical composition distributions compared to polyolefins made with the same unsupported metallocene. A mathematical model was used to quantify this phenomenon, showing that a three-site model was needed to describe the molecular weight distributions of the polyethylene samples made with this catalyst.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Polymer Science
Zahra Rostami Najafabadi, Alvaro A. Omana, Eric Rivard, Joao B. P. Soares
Summary: This study describes the synthesis of ethylene-propylene-diene terpolymers grafted with poly(methyl acrylate) (PMA) by reverse atom transfer radical polymerization, with the molecular weights and densities of PMA grafts being controlled by various factors. The grafted copolymers are characterized by different spectroscopic techniques, and copolymers with a range of graft molecular weights and densities are successfully prepared using this method.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2021)
Article
Engineering, Chemical
Anil K. Mehrotra, Joao B. P. Soares, Krishnaswamy Nandakumar, Pierre J. Carreau, Norman Epstein, Gregory S. Patience
Summary: The history and achievements of The Canadian Journal of Chemical Engineering highlight the multifaceted development of chemical engineering and its crucial role in advancing chemical sciences and engineering.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2022)
Article
Engineering, Chemical
Joao B. P. Soares
Summary: This article introduces a mathematical analysis method to derive the simplest general expression for the moments of the chain length distribution of linear polyolefins. It also demonstrates its application to polyolefins made with different types of coordination catalysts. The article emphasizes the importance of using elegant solutions in polymerization reaction engineering to capture the essential information about complex polymerization systems.
MACROMOLECULAR REACTION ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Fereshte Damavandi, Joao B. P. Soares
Summary: In this study, we designed and synthesized a thermoresponsive organogelator for oil gelling from oil/water mixtures, which plays a significant role in oil spill remediation. The gelators formed porous fibrillar structures with high stiffness, and the three-dimensional networks were created by hydrogen bonding and van der Waals forces. Poly(styrene-co-10-undecenoic acid) has the advantages of a straightforward synthesis procedure, room-temperature conditions, and easy powder delivery, making it an attractive alternative to existing oil spill response methods.
Editorial Material
Engineering, Chemical
Joao B. P. Soares
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Editorial Material
Engineering, Chemical
Joao B. P. Soares, Alexander Penlidis, Hidetaka Tobita, Shiping Zhu
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Engineering, Chemical
Daniel V. Dixon, Joao B. P. Soares
Summary: Population balance models can be used to study the aggregation and fragmentation of particles during flocculation. A new method was used to estimate parameters in a population balance model describing the flocculation of oil sands mature fine tailings using a specific polymer. Unlike previous models, the adsorption data of the polymer onto the suspended particles were used to estimate a fundamental parameter relating polymer dosage to the mean diameter of the aggregates formed during flocculation. The model successfully predicted the flocculation behavior of different polymer samples with varying molecular weights.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Engineering, Chemical
Joao B. P. Soares
Summary: Deconvolution of the molecular weight distribution (MWD) of polyolefins into most probable distributions has been widely used to determine the number of site types on multiple-site-type olefin polymerization catalysts and to study the effects of polymerization conditions. This paper explains the principles behind these deconvolution models, reviews related publications, and proposes a revised formulation for modeling the MWD of polyolefins made with multiple-site-type catalysts. The objective is to highlight the strengths and pitfalls of polyolefin microstructure deconvolution methods.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Engineering, Chemical
Voradon Voraruth, Siripon Anantawaraskul, Saeid Mehdiabadi, Joao B. P. Soares
Summary: Crystallization elution fractionation (CEF) is a newly developed crystallization-based technique used to estimate the chemical composition distribution of ethylene/1-olefin copolymers. A mathematical model was created to describe the CEF mechanism for ethylene/propylene copolymers throughout their compositional range, using population balances for crystallization and dissolution stages. The joint distribution of longest ethylene and isotactic propylene sequences greatly influences the crystallization and dissolution behavior of the copolymer populations. The model's validity was confirmed through experimental CEF profiles of ethylene/propylene copolymers ranging from pure ethylene to propylene homopolymers.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Engineering, Chemical
Daniel V. Dixon, Joao B. P. Soares
Summary: A two-step process using anionic hydrolyzed polyacrylamide (HPAM) and cationic poly(vinylbenzyl trimethylammonium chloride) (PVBTMAC) was employed for flocculating oil sands mature fine tailings (MFT). The optimal HPAM charge density was found to be 32% for fast settling rate and high sediment solids content, but increased to 38% for optimal sediment dewatering. The combination of HPAM and PVBTMAC resulted in clear supernatants and a filter cake with a high solids content of 61 wt.% when filtering undiluted MFT at low pressure (69 kPag).
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Engineering, Chemical
Pooria Karami, Md Mizanul Haque Mizan, Behnam Khorshidi, Sadegh Aghapour Aktij, Ahmad Rahimpour, Joao B. P. Soares, Mohtada Sadrzadeh
Summary: In this study, polyamide membranes with improved water permeability and thermal stability were synthesized for forward osmosis applications. The addition of a polydopamine/graphene oxide interlayer and modification of the chemical composition of the selective layer using TAP monomers resulted in membranes with decreased structural variations and increased resistance at higher temperatures.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
