Article
Chemistry, Multidisciplinary
Mateusz Janeta, Julius X. Heidlas, Olafs Daugulis, Maurice Brookhart
Summary: The reactivity of Ni-II and Pd-II olefin polymerization catalysts can be enhanced by introducing electron-withdrawing substituents on the supporting ligands, as demonstrated in this paper. Compared to the trifluoromethyl group, the trippy substituent shows stronger electron-withdrawing ability, leading to better performance in catalytic turnover frequency and polymer molecular weight.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
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, Multidisciplinary
Hu Zhang, Chen Zou, Huipeng Zhao, Zhengguo Cai, Changle Chen
Summary: In this study, Ni/SiO2 and Pd/SiO2 heterogeneous catalysts were synthesized, with Ni/SiO2 showing high activity in the copolymerization of ethylene with 5-hexene-1-yl-acetate, and Pd/SiO2 mediating ethylene copolymerization with polar monomers with tunable comonomer incorporation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Jin Dong, Congze He, Chaoran Xu, Jie Yun, Xiangcheng Pan
Summary: Boron-containing polymers have attracted great attention in materials science due to their unique recognition, stimulus-response, and dynamic exchange properties. This study successfully introduced vinyl boronic acid and a series of boronate monomers to prepare well-defined polyolefins with boron-containing groups via RAFT polymerization. The resulting polymers exhibited improved thermal stability and showed potential for use as functional materials with dynamic exchange properties.
Article
Polymer Science
Mikhail A. Matsko, Marina I. Nikolaeva, Vladimir A. Zakharov
Summary: The addition of hydrogen leads to a noticeable narrowing of the molecular weight distribution, resulting in polymers and copolymers with lower molecular weights. This suggests that TMC active sites exhibit higher reactivity in chain transfer reactions with hydrogen.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Chemistry, Inorganic & Nuclear
Babak Tahmouresilerd, Dawei Xiao, Loi H. Do
Summary: In this study, two nickel complexes with conformationally rigid bisphosphine mono-oxide ligands were synthesized, showing competent catalytic activities for ethylene homopolymerization and copolymerization. The addition of Li+ to one of the complexes led to a significant enhancement in catalyst activity and polar monomer incorporation, making the nickel-alkali catalysts competitive with other efficient Ni-based systems for ethylene and methyl acrylate copolymerization.
INORGANIC CHEMISTRY
(2021)
Article
Polymer Science
Mohammad Zakaria, Kanta Shibahara, Anamul Hoque Bhuiyan, Koji Nakane
Summary: This study reported a highly efficient nanofibrous membrane made of superfine polypropylene (PP) nanofiber with a direct influence of fiber diameter on its properties and performance for textile wastewater purification. The membrane showed an optimized porosity, high hydrophobicity, and smaller pore size with a narrower distribution due to the finer PP nanofiber construction. It exhibited promising potential for the filtration of dyeing wastewater compared to commercial PP fibrous membranes.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Chemistry, Physical
Reza Bazvand, Naeimeh Bahri-Laleh, Hossein Abedini, Mehdi Nekoomanesh, Albert Poater
Summary: The activation of MgCl2 through the formation of MgCl2 & nEtOH adducts is crucial in the preparation of high performance Ziegler-Natta catalysts for olefins polymerizations in industry. However, the precise structural characterization of these compounds has been neglected due to their complex microstructure. In this study, four MgCl2.nEtOH adducts with different ethanol content were prepared and thoroughly evaluated. Despite the similarities in FTIR spectra, the SEM images showed that the adducts with n = 3.2 had a sticky nature, leading to increased particle size and broader SPAN. XRD spectra confirmed the presence of distinct peaks related to the distorted MgCl2 structure, and the ratio of α-MgCl2 to β-MgCl2 increased with higher ethanol content, which was further supported by DFT calculations. However, it should be noted that this study only provides a simplified characterization of the adducts.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Review
Polymer Science
Martin Pelzer, Thomas Vad, Amrei Becker, Thomas Gries, Svetlana Markova, Vladimir Teplyakov
Summary: This article examines the melt spinning behavior of PMP hollow fibers, finding that the temperature setting in the process significantly affects fiber shape, while increased take-up velocities lead to saturation of crystallinity and a slight reduction in polymer chain orientation.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Polymer Science
Kairui Wang, Lei Chen, Yun Gao, Dengchao Jiang, Yiwu Quan, Shanzhi Yan
Summary: In this study, a polypropylene random copolymer (rPP) and polypropylene/ethylene-propylene-diene monomer graft copolymer (gPP) were added to improve the poor low-temperature tensile properties of polypropylene (PP). The results showed that the addition of rPP reduced the size of PP spherulites and improved the interfacial cohesion of the PP/POE blend, resulting in better tensile properties and melt flow rate. The effects of injection molding process parameters on the mechanical properties and phase morphology of rPP-modified PP/POE blends were also investigated.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Evgueni Kirillov, Jean-Francois Carpentier
Summary: The challenge of developing new metallocene-based polymerization catalysts for manufacturing polyolefinic materials with specific properties continues. By focusing on C-1-symmetric group 4 ansa-metallocenes with multi-substituted fluorenyl-cyclopentadienyl ligands, valuable structural and catalytic data have been used to design more efficient catalytic systems and provide new stereoselective value-added polymer materials.
Article
Engineering, Environmental
Ishaka Muhammad, George Manos
Summary: Pre-degradation treatment improved the performance of catalytic pyrolysis by lowering degradation temperature, increasing liquid yield, and reducing coke yield. The effects of pre-degradation treatment varied depending on the catalyst structure and acidity. ZSM-5 catalyst showed different hydrocarbon yields with high and low Si/Al ratio.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Polymer Science
Suman Kumar Ghosh, Tushar Kanti Das, Sabyasachi Ghosh, Sayan Ganguly, Krishnendu Nath, Narayan Chandra Das
Summary: Inserting 2:1 organo-modified phyllosilicate tactoids into rheologically tough thermoplastics shows great potential in improving oxygen permeability and microstructural toughening. By using commercially abundant clays in low loading, the gas barrier property of thermoplastics was enhanced. The study demonstrates the comparison between organo-clay and simple phyllosilicates, highlighting the improvements in mechanical toughening and gas barrier properties.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Polymer Science
Anibal G. Ferrofino, Marcelo D. Failla, Lidia M. Quinzani
Summary: Blends of PP and EVA with a viscosity ratio of 240 showed a two-phase structure with EVA domains dispersed in the PP matrix, with increasing domain size and crystallization temperature with EVA concentration. The interfacial tension between PP and EVA was found to be very small. Additionally, the presence of EVA increased the degradation temperature and rate of PP.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Polymer Science
Zhonghan Hu, Yuechao Xu, Wenhong Hu, Wanwei Luo, Yu Zhao, Weizhong Huang, Dirong Gong
Summary: The study demonstrates the synthesis of syndiotactic polybutadiene using iron catalysts with robust stability and high activity. The crystallinity of the polymer can be tuned by varying catalyst components, offering potential advantages in applications.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
