The demand for insulating materials with superior dielectric properties has increased. Among these materials, polymers containing cyclic structure including cyclic olefin copolymer (COC) and cyclic olefin polymer (COP) stand out because of their excellent dielectric properties originating from the pure hydrocarbon structure. Introducing fluorine into polymers is one efficient strategy for optimizing the dielectric and the related important properties. Here, three fluorinated norbornene derivatives with high fluorine content are synthesized and copolymerized via coordination-insertion polymerization (CIP) and ring-opening metathesis polymerization (ROMP). The obtained fluorinated COCs and COPs have high fluorine contents (up to 48.2 wt.%) and exhibit excellent dielectric properties with dielectric constant (D) of 2.11-2.24 and dielectric loss (D) of 0.0021-0.0031 at 10 GHz. Moreover, these fluoropolymers show good solvent tolerance, high toughness (elongation at break up to 779%), enhanced thermal stability (T of 427-440 °C), low hydrophilicity (water uptake <0.01%), and excellent gas separation properties. These results imply that these fluoropolymers are suitable as a potential candidate for substrate material utilized in the application of insulating materials.
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http://dx.doi.org/10.1002/marc.202400906 | DOI Listing |
Macromol Rapid Commun
January 2025
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun, 130022, China.
The demand for insulating materials with superior dielectric properties has increased. Among these materials, polymers containing cyclic structure including cyclic olefin copolymer (COC) and cyclic olefin polymer (COP) stand out because of their excellent dielectric properties originating from the pure hydrocarbon structure. Introducing fluorine into polymers is one efficient strategy for optimizing the dielectric and the related important properties.
View Article and Find Full Text PDFEur J Pharm Sci
January 2025
Ludwig-Maximilians-Universität München, Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, 81377 Munich, Germany. Electronic address:
The frozen storage of biopharmaceuticals brings new challenges to the primary packaging material. Due to an increasing demand and the downsides of standard type I glass vials, such as vial breakage, novel vial types for special applications of parenteral drug products have been introduced to the market in the past years. Mechanical stresses due to dimensional changes experienced during freezing and thawing could change the material properties, hence affecting the interaction with the drug product stored in the vial or functionality such as overall integrity.
View Article and Find Full Text PDFChemistry
January 2025
Natinal Institute of Adavanced Industrial Science and Technology, Interdisciplinary Research Center for Catalytic Chemistry, Higashi 1-1-1, 305-8565, Tsukuba, JAPAN.
Unprecedented (2E,4E,6Z,8Z)-nona-2,4,6,8-tetraenoate derivatives highly substituted by aryl groups have been synthesized by the reaction of rhodium complexes having aryl-substituted hexa-1,3,5-trienyl ligands with acrylates. These compounds have potential axial chirality, and their enantiomers are isolable by the chiral HPLC technique. Although the racemization barrier of isolated enantiomers was not high, it was found that a cyclic dimer synthesized by head-to-tail transesterification of a modified analog has quite a stable axial chirality even at a high temperature.
View Article and Find Full Text PDFSci Rep
January 2025
College of Landscape Architecture, Sichuan Agricultural University, Chengdu, 611130, China.
Ethylene is a signalling factor that plays a key role in the response of plants to abiotic stresses, such as cold stress. Recent studies have shown that the exogenous application of 1-aminocyclopropane-1-carboxylate (ACC), an ethylene promoter, affects plant cold tolerance. The cold-responsive specific gene DREB plays a crucial role in enhancing cold tolerance in plants by activating several cold-responsive (COR) genes.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States.
Monoanionic, bidentate-auxiliary-directed, cobalt-catalyzed C-H bond functionalization has become a very useful tool in organic synthesis. A comprehensive investigation into isolated organometallic intermediates and their reactivity within the catalytic cycle is lacking. We report here mechanistic studies of cobalt-catalyzed, aminoquinoline-directed C(sp)-H bond functionalization.
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