Functional Organo-Nano Particles by RAFT Copolymerisation

A significant impact of this work on the use of polymers is expected because the developed organo-nano particles (ONP) mixed into standard polymers will make them unique and traceable. The doping of polymers with non migrating ONP was demonstrated and applications for the recycling of plastics were discussed. Thus, perylene derivatives were linked to polymerisable vinyl groups and copolymerized under RAFT conditions (Reversible Addition Fragmentation chain Transfer) with styrene and methylmethacrylate, respectively, to obtain fluorescent ONP with sizes of 40 nm or even less and narrow distributions of molecular weight in most cases with polydispersities PD of 1.1 and lower

Supercurrent diode effect and magnetochiral anisotropy in few-layer NbSe2_2

Nonreciprocal transport refers to charge transfer processes that are sensitive to the bias polarity. Until recently, nonreciprocal transport was studied only in dissipative systems, where the nonreciprocal quantity is the resistance. Recent experiments have, however, demonstrated nonreciprocal supercurrent leading to the observation of a supercurrent diode effect in Rashba superconductors, opening the vision of dissipationless electronics. Here we report on a supercurrent diode effect in NbSe$_2$ constrictions obtained by patterning NbSe$_2$ flakes with both even and odd layer number. The observed rectification is driven by valley-Zeeman spin-orbit interaction. We demonstrate a rectification efficiency as large as 60%, considerably larger than the efficiency of devices based on Rashba superconductors. In agreement with recent theory for superconducting transition metal dichalcogenides, we show that the effect is driven by an out-of-plane magnetic field component. Remarkably, we find that the effect becomes field-asymmetric in the presence of an additional in-plane field component transverse to the current direction. Supercurrent diodes offer a further degree of freedom in designing superconducting quantum electronics with the high degree of integrability offered by van der Waals materials.Comment: 18 pages, 12 figure

Life cycle assessment of a novel electrocatalytic process for the production of bulk chemical ethylene oxide from biogenic CO2

Carbon capture and utilization (CCU) technologies support future energy and climate transition goals by recycling carbon dioxide (CO2) emissions. The use of biogenic CO2 from renewable sources, is an avenue for the production of fully renewable products. Fossil-based materials can potentially be replaced in the long term while allowing for the use of so called “waste” streams. To foster the development of a circular economy more insights need to be gained on the life cycle impact of CCU technologies. This study analyzed a CCU process chain, with focus on the utilization of volatile renewable electricity and biogenic CO2. We performed a cradle-to-gate life cycle assessment, evaluating various environmental impact categories (CML 2001 methodology) and primary energy demand (PED) with GaBi LCA software by sphera®. The targeted olefin is ethylene oxide (C2H4O), which is a crucial intermediate chemical for the production of various synthetic materials, such as polyethylene terephthalate (PET). As functional unit, 1 kg ethylene oxide was chosen. In the novel process at first ethylene (C2H4) and hydrogen peroxide (H2O2) are produced from water and CO2via an electrocatalytic process (Power-to-X process). In a second step, the two intermediates are synthesized to ethylene oxide. The theoretical implementation of a medium-scale process under average European conditions was considered in 12 scenarios that differed in energy supply and CO2 source. Sensitivity analyses were conducted to evaluate the influence of the energy and resource efficiencies of the production steps. The process was compared to its fossil benchmark, an existing conventional EO production chain. Concerning the global warming potential (GWP), negative emissions of up to −0.5 kg CO2 eq./kg product were calculated under optimized process conditions regarding energy and conversion efficiency and using biogenic CO2. In contrast, the GWP exceeded the fossil benchmark when the European grid mix was applied. The PED of 87 MJ/kg product under optimized conditions is comparable to that of other Power-to-X processes, but is high compared to fossil-based ethylene oxide. Based on the results we conclude that the energy efficiency of the electrocatalytic cell and renewable energy as input are the main levers to achieve a low environmental impact

Toward Global Soil Moisture Monitoring With Sentinel-1: Harnessing Assets and Overcoming Obstacles

The final authenticated publication is available at https://doi.org/10.1109/TGRS.2018.2858004.Soil moisture is a key environmental variable, important to, e.g., farmers, meteorologists, and disaster management units. Here, we present a method to retrieve surface soil moisture (SSM) from the Sentinel-1 (S-1) satellites, which carry C-band Synthetic Aperture Radar (CSAR) sensors that provide the richest freely available SAR data source so far, unprecedented in accuracy and coverage. Our SSM retrieval method, adapting well-established change detection algorithms, builds the first globally deployable soil moisture observation data set with 1-km resolution. This paper provides an algorithm formulation to be operated in data cube architectures and high-performance computing environments. It includes the novel dynamic Gaussian upscaling method for spatial upscaling of SAR imagery, harnessing its field-scale information and successfully mitigating effects from the SAR's high signal complexity. Also, a new regression-based approach for estimating the radar slope is defined, coping with Sentinel-1's inhomogeneity in spatial coverage. We employ the S-1 SSM algorithm on a 3-year S-1 data cube over Italy, obtaining a consistent set of model parameters and product masks, unperturbed by coverage discontinuities. An evaluation of therefrom generated S-1 SSM data, involving a 1-km soil water balance model over Umbria, yields high agreement over plains and agricultural areas, with low agreement over forests and strong topography. While positive biases during the growing season are detected, the excellent capability to capture small-scale soil moisture changes as from rainfall or irrigation is evident. The S-1 SSM is currently in preparation toward operational product dissemination in the Copernicus Global Land Service.5205392

Polypropylene Copolymers Designed for Fused Filament Fabrication 3DPrinting

Several chemical properties which influence the printability for fused filament fabrication 3Dprinting are derived from analyses of commercially available filaments. In preliminary experiments, polymerization conditions are optimized and suitable monomers and selectivity control agents (donors) are selected. An experimental series in which propene is copolymerized with the comonomers 1butene and 1hexene with an industrial ZieglerNatta catalyst will be discussed here. The experiments are planned using design of experiments. Based on a splitplot design, the design is adapted for mixtures and the combination of homo and copolymerization. The observed factors, besides the mixture composition, are hydrogen partial pressure and the amount of donor. The obtained polymers are analyzed by means of hightemperature size exclusion chromatography, differential scanning calorimetry, and rheology. 1Butene copolymers show good printing results and promising properties almost matching the desired ones. The targeted polymer properties are achieved within certain limits. 1Hexene copolymers result in lower molecular masses while crystallinity remains slightly higher, which does not match with the desired profile. Beneficial properties are likely to be achieved within a wider factor range, for example, higher comonomer amount and lower hydrogen partial pressure.(VLID)4844485Version of recor

Photoinitiatorfree photopolymerization of acrylatebismaleimide mixtures and their application for inkjet printing

There is growing interest in using photoinitiatorfree systems in coating applications such as inkjetprinting, because residual photoinitiator can alter the properties of the resulting polymer. Bismaleimides (BMI) offer the opportunity to polymerize acrylates without the addition of photoinitiators, as this class of molecules can serve both as polymerizable monomer and as photoinitiator together with electron donor systems, like vinyl ether monomers or acrylates. The UVinduced copolymerization of a lowmolecularweight BMI with various acrylate monomers and oligomers without any photoinitiator was characterized. The BMIacrylate systems show comparable polymerization speeds to widely used acrylic systems with photoinitiator. Superior thermal stability as well as thermomechanical properties are achieved by enhancing acrylics with BMI. Such photoinitiatorfree systems lend themselves to be used for lowmigration coatings as well as for hightemperature applications. Here, a characterization of selected BMIacrylate mixtures regarding their photocuring kinetics and their application as inks for inkjet printing is shown.(VLID)361611