Poly(norbornene--styrene)s were synthesized by the use of anilinonaphthoquinone-ligated nickel complexes [Ni(CHONAr)(Ph)(PPh): , Ar = CH-2,6-Pr; , Ar = CH-2,4,6-Me; , Ar = CH] activated with modified methylaluminoxane (MMAO) or B(CF) in toluene. The effects of the cocatalysts were more significant than those of the nickel complexes, and MMAO gave higher activity than B(CF). The structural characterizations of the products indicated the formation of statistical norbornene copolymers. An increase of the styrene ratio in feed led to an increase in the incorporated styrene (S) content of the resulting copolymer. The molecular weight of the copolymer decreased with increasing the S ratio in feed at 70 °C. The copolymerization activity, using MMAO as a cocatalyst, decreased with lowering of the temperature from 70 to 0 °C, accompanied by an increase in the molecular weight of the copolymer. The S incorporation up to 59% with of 78,000 was achieved by the B(CF) catalytic system. The glass transition temperatures of the norbornene (N)/S copolymers determined by differential scanning calorimetry, decreased from 329 to 128 °C according to the S content.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6680643 | PMC |
| http://dx.doi.org/10.3390/polym11071100 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Sterically Induced Enhancement in the Electrochemical Stability of Salen-Type Cathode Materials.
Polymers (Basel)
January 2025
Department of Chemistry, St. Petersburg University, Universitetskaya nab., 7/9, Saint Petersburg 199034, Russia.
This study investigates the electrochemical degradation mechanisms of nickel-salen (NiSalen) polymers, with a focus on improving the material's stability in supercapacitor applications. We analyzed the effects of steric hindrance near the nickel center by incorporating different bulky substituents into NiSalen complexes, aiming to mitigate water-induced degradation. Electrochemical performance was assessed using cyclic voltammetry, operando conductance, and impedance measurements, while X-ray photoelectron spectroscopy (XPS) provided insights into molecular degradation pathways.
View Article and Find Full Text PDFComplex Inhibitor Protection of Some Steels in Hydrochloric Acid Solutions by 1,2,4-Triazole Derivatives.
Materials (Basel)
January 2025
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia.
The behavior of low-carbon steels (LCSs), a high-strength steel and a nickel-chromium alloy in HCl solutions in the presence of N-containing organic substances has been studied. N-containing organic substances that comprise 1,2,4-triazole in their structure (substance I and substance II) provide comprehensive protection of various steel grades from corrosion and hydrogen absorption by the metal bulk in HCl solutions under both isobaric and isochoric conditions. All the compounds studied reduce, to varying degrees, the concentration of hydrogen adsorbed and absorbed by steel in HCl solutions.
View Article and Find Full Text PDFReview of the Microstructural Impact on Creep Mechanisms and Performance for Laser Powder Bed Fusion Inconel 718.
Materials (Basel)
January 2025
ArGEnCo Department, MSM Team, University of Liège, Quartier Polytech 1, Allée de la Découverte 9 (B52), 4000 Liège, Belgium.
Inconel 718 (IN718) is a polycrystalline nickel-based superalloy and one of the most widely used materials in the aerospace industry owing to its excellent mechanical performances at high temperatures, including creep resistance. Interest in additively manufactured components in aerospace is greatly increasing due to their ability to reduce material consumption, to manufacture complex parts, and to produce out-of-equilibrium microstructures, which can be beneficial for mechanical behavior. IN718's properties are, however, very sensitive to microstructural features, which strongly depend on the manufacturing process and subsequent heat treatments.
View Article and Find Full Text PDFSelf-healing behavior of metallopolymers in complex.
Chemistry
January 2025
Friedrich-Schiller-Universität Jena: Friedrich-Schiller-Universitat Jena, Laboratory of Organic and Macromolecular Chemistry, GERMANY.
This current study focusses on the investigation of the self-healing abilities of metallopolymers containing different kinds of metal complexes, which were processed by direct digital light processing (DLP) based three-dimensional (3D) printing. For this purpose, 2‑phenoxyethyl acrylate is mixed with ligand-containing monomers either based on triphenylmethyl(trt)-histidine or terpyridine, respectively. Either zinc(II) or nickel(II) salts are successfully applied for a complexation of the ligand monomers in solution and, subsequently, photopolymerization is performed.
View Article and Find Full Text PDFTrace Element Speciation and Nutrient Distribution in : Evaluation and Toxic Metal Concentration Across Plant Tissues.
Toxics
December 2024
Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
This study investigated the elemental composition of , addressing the gap in comprehensive trace element profiling of this medicinal plant. The research aimed to determine the distribution of macronutrients, micronutrients, and beneficial and potentially toxic elements across different plant parts (seeds, leaves, stems, and roots). Using ICP-OES analysis, two digestion methods were employed to capture both complex and labile elements.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!