jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: M. Barletta | Clizia Aversa | Elisa Pizzi | M. Puopolo
Source: Journal of Applied Polymer Science (article, 2019-11-26)
Field: Materials Science — Biomaterials

Advance on processing of compostable and thermally stable biodegradable polyester blends ABSTRACT Flexible and semiflexible packagings can be manufactured by cast extrusion of plastic sheet and thermoforming of containers. Thermal stability is often required as packaging items after being thermoformed can come in contact with hot food/beverage, especially during hot filling operations. In this framework, the present study deals with the design and manufacturing by thermoforming of plastic containers that are, at the same time, compostable and suitable for high‐temperature applications (~100 °C). First, extrusion compounding of Poly( l ‐lactic acid) (PLLA)‐based biodegradable polyester blends was performed. In particular, the effect on the material properties of different types of nucleating agents was investigated. Combinations of micro‐lamellar talc, poly( d ‐lactic acid) (PDLA), ethylene bisstearamide (EBS), and titanium dioxide (TiO 2 ) were studied. The formulations involving EBS boast the highest crystallinity and the fastest onset of the crystalline phase on sheets produced by cast extrusion. Conversely, the formulations involving TiO 2 feature the lowest degree of crystallinity and the slowest onset of the crystalline phase. Combinations of talc and PDLA exhibit an intermediate behavior. Second, thermoforming of the plastic foils was performed. A very different trend of the crystallization after thermoforming is shown. Indeed, crystallinity is the highest for the formulations involving talc and PDLA, the lowest for the ones containing EBS. In conclusion, the biodegradable polyester blends are found to be suitable for the manufacturing of compostable and thermostable packaging items by cast extrusion and thermoforming. Final crystallization of the material and the resulting thermal stability can be fine‐tuned by modulating type and amount of nucleating agents. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48722. Thermoforming ; Crystallinity ; Materials science ; Polyester ; Extrusion ; Compounding ; Composite material ; Talc ; Crystallization ; Thermal stability ; Blow molding ; Chemical engineering biodegradable polymer synthesis and properties ; Microplastics and Plastic Pollution ; Additive Manufacturing and 3D Printing Technologies
Authors: Vojislav Jovanović | Ivan Ristić | Aleksandra Miletić | Suzana Cakić | Jelena Tanasić | Jaroslava Budìnski‐Simendìć
Source: University thought - Publication in Natural Sciences (article, 2019-01-01)
Field: Materials Science — Biomaterials

Synthesis of biodegradable polyester based on renewable resources Due to the growing problem caused by waste plastics, academia and industry, invest great dials of efforts to solve this problem and enable the sustainability of polymeric materials. One way, which can successfully solve this problem, is certainly the synthesis of new polymeric materials based on renewable raw materials. Therefore, in this paper, synthesis of polyester based on ricinoleic acid (as well as the methyl ester of ricinoleic acid) is presented, in order to obtain the polyol of the desired molar masses. The polymerization of the ricinoleic acid was performed in the presence of diethylene glycol, as an initiator, and titanium isopropoxide, as a catalyst. By analyzing the molar masses of the obtained polyesters, it has been confirmed that the control of the molecular weight of the polyricinoleic acid can be successfully accomplished by the addition of a precisely determined amount of diethylene glycol, thus enabling in this way the synthesis of polyols of desired properties. The molecular structure of the synthesized polyols is confirmed by FTIR and NMR spectroscopy. The analysis of the thermal properties showed that the glass transition temperatures of the synthesized polyols range from -70 to -80ºC, which makes it possible to apply these materials in low-temperature applications. The slight increasment of thermal stability is observed, only with the increasment of molecular weight, which was confirmed by TG analysis. The viscosity measurement results confirmed that as the molar weight of synthesized polyester increases, the viscosity of the samples also increases. Diethylene glycol ; Ricinoleic acid ; Polyester ; Molar mass ; Polyol ; Materials science ; Adipic acid ; Polymer ; Chemical engineering ; Raw material ; Glass transition ; Hydroxyl value ; Polymerization ; Thermal stability ; Polymer chemistry ; Organic chemistry ; Chemistry ; Ethylene glycol ; Composite material ; Castor oil ; Polyurethane biodegradable polymer synthesis and properties ; Carbon dioxide utilization in catalysis ; Polymer composites and self-healing
Authors: Christoph Bernhard | Steven J. Roeters | Kristin Bauer | Tobias Weidner | Mischa Bonn | Frederik R. Wurm | Grazia Gonella
Source: Langmuir (article, 2019-09-30)
Field: Materials Science — Surfaces, Coatings and Films

Both Poly(ethylene glycol) and Poly(methyl ethylene phosphate) Guide Oriented Adsorption of Specific Proteins Developing new functional biomaterials requires the ability to simultaneously repel unwanted and guide wanted protein adsorption. Here, we systematically interrogate the factors determining the protein adsorption by comparing the behaviors of different polymeric surfaces, poly(ethylene glycol) and a poly(phosphoester), and five different natural proteins. Interestingly we observe that, at densities comparable to those used in nanocarrier functionalization, the same proteins are either adsorbed (fibrinogen, human serum albumin, and transferrin) or repelled (immunoglobulin G and lysozyme) by both polymers. However, when adsorption takes place, the specific surface dictates the amount and orientation of each protein. Lysozyme ; Ethylene glycol ; Adsorption ; Protein adsorption ; Chemistry ; Polymer ; Surface modification ; Polymer chemistry ; Chemical engineering ; PEG ratio ; Organic chemistry ; Biochemistry Polymer Surface Interaction Studies ; Microfluidic and Bio-sensing Technologies ; Advanced Biosensing Techniques and Applications
Authors: Debbie C. Crans | Irma Sánchez‐Lombardo | C.C. McLauchlan
Source: Frontiers in Chemistry (article, 2019-07-05)
Field: Materials Science — Materials Chemistry

Exploring Wells-Dawson Clusters Associated With the Small Ribosomal Subunit The polyoxometalate P<sub>2</sub>W<sub>18</sub> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow> <mml:mrow><mml:mn>62</mml:mn></mml:mrow> <mml:mrow><mml:mn>6</mml:mn> <mml:mo>-</mml:mo></mml:mrow> </mml:msubsup> </mml:math> , the Wells-Dawson cluster, stabilized the ribosome sufficiently for the crystallographers to solve the phase problem and improve the structural resolution. In the following we characterize the interaction of the Wells-Dawson cluster with the ribosome small subunit. There are 14 different P<sub>2</sub>W<sub>18</sub> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow> <mml:mrow><mml:mn>62</mml:mn></mml:mrow> <mml:mrow><mml:mn>6</mml:mn> <mml:mo>-</mml:mo></mml:mrow> </mml:msubsup> </mml:math> clusters interacting with the ribosome, and the types of interactions range from one simple residue interaction to complex association of multiple sites including backbone interactions with a Wells-Dawson cluster. Although well-documented that bridging oxygen atoms are the main basic sites on other polyoxometalate interaction with most proteins reported, the W=O groups are the main sites of the Wells-Dawson cluster interacting with the ribosome. Furthermore, the peptide chain backbone on the ribosome host constitutes the main sites that associate with the Wells-Dawson cluster. In this work we investigate the potential of one representative pair of closely-located Wells-Dawson clusters being a genuine Double Wells-Dawson cluster. We found that the Double Wells-Dawson structure on the ribosome is geometrically sound and in line with other Double Wells-Dawson clusters previously observed in the solid state and solution. This information suggests that the Double Wells-Dawson structure on the ribosome is real and contribute to characterization of this particular structure of the ribosome. Polyoxometalate ; Ribosome ; Cluster (spacecraft) ; Chemistry ; A-site ; Protein subunit ; Ribosomal RNA ; Crystallography ; Chemical physics ; Physics ; RNA ; Binding site ; Biochemistry Polyoxometalates: Synthesis and Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Corrosion Behavior and Inhibition
Authors: Anna Makal | Joanna Krzeszczakowska | Roman Gajda
Source: Molecules (article, 2019-03-20)
Field: Materials Science — Materials Chemistry

Pressure-Dependent Structural and Luminescence Properties of 1-(Pyren-1-yl)but-2-yn-1-one The crystal structure of 1-(pyren-1-yl)but-2-yn-1-one ( 1 a , a polynuclear aromatic hydrocarbon displaying enhanced luminescence in the solid state, has been re-determined at several pressures ranging from atmospheric up to 3 GPa using a Diamond Anvil Cell (DAC). These experiments were augmented by periodic DFT calculations at pressures up to 4.4 GPa. UV-Vis fluorescence of 1 a at non-ambient pressures has also been investigated. The crystal structure consists of infinite π -stacks of anti-parallel 1 a molecules with discernible dimers, which may exemplify aggregates formed by pyrene derivatives in solution and thin films, and is predominantly stabilized by dispersion. The average inter-planar distance between individual molecules within π -stacks decreases with pressure in the investigated range. This results in piezochromic properties of 1 a : a red-shift of sample color, as well as a bathochromic shift of fluorescence with pressure (by ca. 100 nm at 3.5 GPa). Two-component fluorescence spectra support the hypothesis that at least two types of excimers are involved in the electronic excitation processes in crystalline 1 a . Bathochromic shift ; Luminescence ; Fluorescence ; Molecule ; Crystal (programming language) ; Pyrene ; Chemistry ; Dispersion (optics) ; Crystal structure ; Analytical Chemistry (journal) ; Excitation ; Emission spectrum ; Crystallography ; Spectral line ; Photochemistry ; Materials science ; Organic chemistry ; Optics ; Optoelectronics Luminescence and Fluorescent Materials ; Photochemistry and Electron Transfer Studies ; Crystallography and molecular interactions
Authors: Joshua Stuckner | Katherine Frei | Sean G. Corcoran | W. T. Reynolds | Mitsuhiro Murayama
Source: Journal of Physics and Chemistry of Solids (article, 2019-08-08)
Field: Materials Science — Materials Chemistry

Assessing the influence of processing parameters and external loading on the nanoporous structure and morphology of nanoporous gold toward catalytic applications Nanoporous ; Materials science ; Morphology (biology) ; Composite material ; Nanoscopic scale ; Curvature ; Ligament ; Ultimate tensile strength ; Nanotechnology ; Brittleness ; Deformation (meteorology) ; Geometry Nanoporous metals and alloys ; Electrocatalysts for Energy Conversion ; Supercapacitor Materials and Fabrication
Authors: Irina A. Kühne | Liviu Ungur | Kane Esien | Anthony B. Carter | John D. Gordon | Cameron Pauly | Helge Müller‐Bunz | Solveig Felton | Dominic Zerulla | Grace G. Morgan
Source: Dalton Transactions (article, 2019-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Comparison of two field-induced Er<sup>III</sup> single ion magnets We present the synthesis, magnetic and photophysical properties of four mononuclear Ln<sup>III</sup> complexes in two isostructural lattices containing Gd<sup>III</sup> and Er<sup>III</sup>. A heptadentate Schiff base ligand and acetate versus trifluoroacetate were used to synthesise complexes 1-4, among which the two Er<sup>III</sup> complexes 2 and 4 exhibit field-induced SIM behaviour with almost similar U<sub>eff</sub> values (31.6 K for 2 and 32.7 K for 4). Ab initio calculations show the structure of the low-lying energy states and highlight that there is already significant tunnelling in the ground doublet state, but the application of a weak magnetic field of 0.05 T is sufficient for ac magnetic measurements to suppress tunnelling in the ground state. The calculated main magnetic axes (g<sub>Z</sub>) of the ground Kramers doublets show small differences between the two Er<sup>III</sup> compounds 2 and 4 due to their different ligand fields. Magnet ; Ion ; Erbium ; Field (mathematics) ; Chemistry ; Crystallography ; Materials science ; Atomic physics ; Analytical Chemistry (journal) ; Nuclear magnetic resonance ; Physics ; Condensed matter physics ; Doping Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies
Authors: Valentina Pirovano | Giorgio Abbiati | Elisa Brambilla | Elisabetta Rossi
Source: European Journal of Inorganic Chemistry (article, 2019-11-15)
Field: Chemistry — Organic Chemistry

Vinyl‐/Furoindoles and Gold Catalysis: New Achievements and Future Perspectives for the Synthesis of Complex Indole Derivatives The reactivity of vinyl‐/furoindole derivatives with gold‐activated π‐systems is the subject of extensive investigation. In the presence of these electrophilic partners, the realized transformations allow for the construction of different and fascinating architectures via cycloaddition and cyclization reactions often included in cascade processes. The reactions realized involving in these processes an external substituent at the indole moiety are the subject of the present minireview. Chemistry ; Indole test ; Moiety ; Electrophile ; Reactivity (psychology) ; Substituent ; Cycloaddition ; Combinatorial chemistry ; Catalysis ; Organic chemistry Catalytic Alkyne Reactions ; Catalytic C–H Functionalization Methods ; Oxidative Organic Chemistry Reactions
Authors: Carles Corbella | Sabine Portal | M. A. S. R. Saadi | Santiago D. Solares | Madhusudhan Kundrapu | Michael Keidar
Source: Plasma Research Express (article, 2019-12-12)
Field: Materials Science — Materials Chemistry

Few-layer flakes of Molybdenum Disulphide produced by anodic arc discharge in pulsed mode Abstract Here, the synthesis of Molybdenum Disulphide (MoS 2 ) flakes by means of anodic atmospheric arc discharge is reported for the first time. The vertical electrode configuration consisted of a compound anode (hollow graphite anode filled with MoS 2 powder) and a solid graphite cathode placed just above of the compound anode. Arc processes were operated in pulsed mode to preferentially evaporate the powder component from the anode and to minimize Carbon ablation. Pulsed anodic arc discharges were conducted at 2 Hz and 10% duty cycle in 300 Torr of Helium with a peak current of 250–300 A and a peak voltage of 35 V. A probe made of Tungsten wire was placed in the vicinity of the arc column to collect the evaporated material. The measured thickness profile was correlated to the particle flux distribution and it was fitted by a simple model of plasma expansion. During pulse phase, electron density was estimated around 5 × 10 22 m −3 or higher, and ion current density was of the order of 10 A mm −2 . Morphology, structure and composition of the samples were characterized by Raman spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The study shows that pulsed arc discharge of the compound anode leads to moderate C deposition combined with MoS 2 deposition in the form of fragmented nanocrystals and few atomic monolayers of MoS 2 . Such synthesis technique is promising to produce new 2D nanomaterials with tailored structure and functionality thanks to the flexibility of pulsed power. Anode ; Materials science ; Scanning electron microscope ; Analytical Chemistry (journal) ; Transmission electron microscopy ; Tungsten ; Electric arc ; Raman spectroscopy ; Cathode ; Electrode ; Nanotechnology ; Composite material ; Chemistry ; Optics ; Metallurgy 2D Materials and Applications ; MXene and MAX Phase Materials ; Graphene research and applications
Authors: Francesca Nunzi | Benedetta Di Erasmo | Francesco Tarantelli | David Cappelletti | Fernando Pirani
Source: Molecules (article, 2019-11-23)
Field: Chemistry — Inorganic Chemistry

The Halogen-Bond Nature in Noble Gas–Dihalogen Complexes from Scattering Experiments and Ab Initio Calculations In order to clarify the nature of the halogen bond (XB), we considered the prototype noble gas-dihalogen molecule (Ng-X<sub>2</sub>) systems, focusing on the nature, range, and strength of the interaction. We exploited data gained from molecular beam scattering experiments with the measure of interference effects to obtain a suitable formulation of the interaction potential, with the support of high-level ab initio calculations, and charge displacement analysis. The essential interaction components involved in the Ng-X<sub>2</sub> adducts were characterized, pointing at their critical balance in the definition of the XB. Particular emphasis is devoted to the energy stability of the orientational Ng-X<sub>2</sub> isomers, the barrier for the X<sub>2</sub> hindered rotation, and the influence of the X<sub>2</sub> electronic state. The present integrated study returns reliable force fields for molecular dynamic simulations in Ng-X<sub>2</sub> complexes that can be extended to systems with increasing complexity and whose properties depend on the selective formation of XB. Chemistry ; Ab initio ; Noble gas ; Ab initio quantum chemistry methods ; Scattering ; Chemical physics ; Molecule ; Halogen bond ; Computational chemistry ; Physics ; Quantum mechanics ; Organic chemistry ; Hydrogen bond Inorganic Fluorides and Related Compounds ; Crystallography and molecular interactions ; Advanced Chemical Physics Studies
Authors: Kristian Bader | P. Gille
Source: Crystal Research and Technology (article, 2019-09-16)
Field: Materials Science — Materials Chemistry

Single Crystal Growth of FeGa<sub>3</sub> and FeGa<sub>3−<i>x</i></sub>Ge<i><sub>x</sub></i> from High‐Temperature Solution Using the Czochralski Method Abstract Single crystal growth and characterization of the binary semiconducting compound FeGa 3 and its Ge‐substitute FeGa 3– x Ge x are reported. Whereas there have been several investigations on the thermoelectric properties based on small samples grown by the flux method, this study is the first approach using the Czochralski growth technique from well‐oriented single‐crystalline seeds. Problems and solutions of the growth of cm 3 ‐size single crystals are discussed in detail. Ge segregation in FeGa 3– x Ge x is described by a segregation coefficient lower than unity which leads to an axially increasing Ge content along the pulling direction. Consequences with respect to lattice parameter changes and thermoanalytic measurements are reported. Crystal growth ; Materials science ; Crystallography ; Intermetallic ; Czochralski method ; Single crystal ; Thermoelectric effect ; Crystal structure ; Lattice constant ; Solid solution ; Axial symmetry ; Thermodynamics ; Condensed matter physics ; Diffraction ; Chemistry ; Physics ; Optics ; Metallurgy Advanced Thermoelectric Materials and Devices ; Magnetic and transport properties of perovskites and related materials ; Heusler alloys: electronic and magnetic properties
Authors: Maria I. Lapuh | Alejandro L. Dana | Pablo H. Di Chenna | Benjamin Darses | Fernando Durán | Philippe Dauban
Source: Organic & Biomolecular Chemistry (article, 2019-01-01)
Field: Chemistry — Inorganic Chemistry

Late-stage C–H amination of abietane diterpenoids This study aims at highlighting the synthetic versatility of the rhodium-catalyzed C-H amination reactions using iodine(iii) oxidants for the late-stage functionalization of natural products. Inter- and intramolecular nitrene insertions have been performed from various abietane diterpenoids, leading to the amination of the C-3, C-6, C-7, C-11 and C-15 positions. Ca. 20 aminated compounds have been isolated with yields of up to 86% and high levels of regio-, chemo- and stereoselectivities. Abietane ; Amination ; Stage (stratigraphy) ; Chemistry ; Stereochemistry ; Terpenoid ; Organic chemistry ; Biology Metal-Catalyzed Oxygenation Mechanisms ; Microbial Natural Products and Biosynthesis ; Synthesis and Catalytic Reactions
Authors: Yu. É. Burunkova | S. Molnár | Vera E. Sitnikova | D. Shaimadiyeva | George Alkhalil | R. Bohdan | József Bakó | F. Kolotaev | Attila Bonyár | S. Kökényesi
Source: Journal of Materials Science Materials in Electronics (article, 2019-04-12)
Field: Materials Science — Materials Chemistry

Polymer–chalcogenide glass nanocomposites for amplitude–phase modulated optical relief recording The main objective of this work was to combine the positive characteristics of transparent photopolymers and light-sensitive chalcogenide glasses, with aim to improve the amplitude–phase modulation characteristics of in situ optically recorded photonic elements on the surface, and in the bulk of thick composite layer on a given substrate. The positive results were obtained due to the developed technology routes of nanocomposite (NC) fabrication by intermixing selected, optically tunable, VIS–NIR transparent and high refractive index As-S (Se) nanoparticles (NPs) produced by chemical dissolution, and acrylate monomers with initiators. Subsequent photopolymerization of such nanocomposite occurs during optical recording photonic elements and is supplemented by mass-transport processes, which enhance relief parameters. Structure, optical parameters of the new light-sensitive media and conditions of one step recording of optical elements in it were investigated. Materials science ; Nanocomposite ; Chalcogenide ; Photopolymer ; Refractive index ; Photonics ; Optoelectronics ; Fabrication ; Substrate (aquarium) ; Phase (matter) ; Embossing ; Polymer ; 3D optical data storage ; Layer (electronics) ; Chalcogenide glass ; Optical recording ; Monomer ; Composite material ; Chemistry ; Organic chemistry Phase-change materials and chalcogenides ; Glass properties and applications ; Nonlinear Optical Materials Studies