Quasiliving cationic ring-opening polymerization of 2-ethyl-2-oxazoline in benzotrifluoride, as an alternative reaction medium

Cationic ring-opening polymerization (CROP) of 2-ethyl-2-oxazoline (EtOx) was systematically investigated in benzotrifluoride (BTF), which is considered as an environmentally less harmful solvent than many conventional reaction media. Simultaneously, polymerizations in conventional solvents, such as acetonitrile, N,N-dimethylacetamide and toluene, were also carried out for comparison in the 80-100 degrees C temperature range. Kinetic experiments revealed that the monomer consumption occurs by first order kinetics and the number average molecular weights linearly increase in line with the theoretical molecular weight as a function of monomer conversion. These findings indicate that the polymerization takes place by quasiliving CROP in all the investigated solvents, including BTF as well, resulting in PEtOx with prederminded molecular weights and polydispersities of 1.3-15. The highest polymerization rates were obtained in BTF, resulting in high conversions in short reaction times at 100 degrees C reaction temperature. The Arrhenius parameters of the polymerization of EtOx in BTF indicates relatively high activation energy in comparison with other applied solvents, however, a compensation effect between the activation energies and frequency factor is observed for such polymerization in a variety of solvents. Our findings are expected to enable the convenient synthesis of polyoxazolines and polyoxazoline-based well-defined polymer architectures in BTF, an environmentally advantageous alternative solvent to harmful polymerization media, with high polymerization rates in short reaction times without the need for any special conditions or equipment.Peer reviewe

Novel biobased amines

The present invention relates to a method for producing an amidoamine by reacting a triacid derivative (I) with at least one amine (A), the at least one amine (A) being selected from diethylene triamine and a diamine (II). The molar ratio of the triacid derivative (I) to the at least one amine (A) is in the range of 1 : 2 to 1 : <3. The present invention further relates to the amidoamine as such,and to the use of said amidoamine as a cross-linking agent

Capillary pressure in graphene oxide nanoporous membranes for enhanced heat transport in Loop Heat Pipes for aeronautics

We describe a novel application of graphene-based materials to enhance heat transport in sintered metal wicks, which are the core components for Loop Heat Pipe (LHP) evaporators. Standard metal wicks limit the applicability of LHP to about 8-10 m of transport length and around few meters of gravitational head. This is due to the typical average pore size (about 1 μm) in the sintered metal wicks made of nickel or titanium, which are the most commonly used materials. The idea of the present work is to bond a layer of graphene on top of the wick facing the vapor side of the LHP evaporator. The much smaller pore sizes of graphene (around tens of nanometers) would produce a significant increase in capillary force, while at the same time minimising the pressure drop due to its microscopic thickness (few microns). The wicking height (i.e. capillary rise of a liquid inside a pore) measurements demonstrate that there is an improvement of at least more than 3.5 times when the graphene coating is used, compared to the standard nickel sintered powder wick. This means that the heat transfer of a graphene LHP could work in a spatial range in excess of 28-35 m, which would allow breakthrough applications such as anti-icing of aircraft wings and propellers, as well as wind turbines that cannot be addressed by standard LHP technology.SCOPUS: ar.jinfo:eu-repo/semantics/publishe