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http://dx.doi.org/10.1103/physrevb.53.3680 | DOI Listing |
Macromol Rapid Commun
January 2025
Department of Advanced Materials Engineering, Chung-Ang University, Anseong, 17546, Republic of Korea.
Transport equipment manufacturers in the automotive and aerospace industries are focused on developing materials that enhance fuel efficiency and reduce carbon dioxide emissions. A significant approach is employing lightweight materials like aluminum, magnesium, and polymer-based composites. Polyamide-based composites, particularly nylon 66, as viable alternatives due to their excellent rigidity, chemical resistance, and thermal stability are investigated to address the limitations of traditional thermosetting resins, which are difficult to recycle and have lengthy molding processes that hinder mass production.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK.
Negative thermal expansion is known to exist in a range of structure types but is extremely rare in hexagonal perovskites. Here we demonstrate that BaIrO displays negative linear thermal expansion in the direction of its face-shared IrO trimers, and apparent zero volume thermal expansion below 100 K. We present evidence that this anomalous thermal expansion is driven by an unusual form of rigid body phonon behaviour governed by the effective trimer valence state and therefore has structural and electronic components to the underlying mechanism.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Materials Science, Case Western Reserve University, Cleveland, 44106, USA.
Understanding subsurface temperature variations is crucial for assessing material degradation in underground structures. This study maps subsurface temperatures across the contiguous United States for depths from 50 to 3500 m, comparing linear interpolation, gradient boosting (LightGBM), neural networks, and a novel hybrid approach combining linear interpolation with LightGBM. Results reveal heterogeneous temperature patterns both horizontally and vertically.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Industrial Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece.
Well-defined amorphous/semi-crystalline statistical copolymers of n-dodecyl isocyanate, DDIC, and allyl isocyanate, ALIC, were synthesized via coordination polymerization using the chiral half-titanocene complex CpTiCl(O-(S)-2-Bu) as an initiator. In the frame of the terminal model, the monomer reactivity ratios of the statistical copolymers were calculated using both well-known linear graphical methods and the computer program COPOINT. The molecular and structural characteristics of the copolymers were also calculated.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland.
The aim of this work was to synthesize polyurethane foams based on petrochemical polyols and biopolyols with specific apparent densities (40, 60, 80, 100, and 120 kg/m), test their properties, glycolyze them, and finally analyze each glycolyzed product. The petroleum-based foams, used as reference foams, and the bio-based foams underwent a series of standard tests to define their properties (the content of closed cells 20-95%, compressive strength 73-1323 kPa, thermal conductivity 24-42 mW/m∙K, brittleness 4.6-82.
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