A new bifunctional coupling agent: synthesis and model reactions

The preparation of a new bifunctional coupling agent with one oxazoline group and one oxazinone group has been described. Model reactions with dodecanoic acid, benzoic acid, n‐dodecyl alcohol and n‐dodecylamine in melt evidenced that both carboxylic acids react selectively with the oxazoline group whereas the oxazinone group is exclusively attacked by the amino and the hydroxy compound, respectively. In blends of amino group terminated polyethers with a carboxy group containing polyethylene the new coupling agent has proven very effective.     

Bulk and surface properties of blends with semifluorinated polymers and block copolymers

The goal of the investigation presented here is the development of extremely hydrophobic materials based on polysulfone that can be applied, for instance, as fouling-resistant membrane materials. The concept used is the addition of semifluorinated polymers to polysulfone in suitable blend compositions. The influence of molecular parameters like chain structure of the semifluorinated polymer (segmented block copolymers, random copolymers) and segment molecular weight on the state of phase separation in the bulk and its influence on the surface properties have been systematically examined. It could be shown that segmented block copolymers with semifluorinated polyester segments with intermediate segment molecular weight are more suitable in blends with polysulfone than random polysulfone copolymers having semifluorinated side chains with respect to form homogeneous thin films (coatings) with highly non-wetting properties.     

Electrochemical Sulphenylation/Cyclization of Quinones: A Rapid,Green, and Efficient Access to Cytotoxic Compounds

Undivided electrochemical cells enable economical preparation of sulphur-containing naphthoquinones through electrochemical sulphenylation of quinoidal compounds. The environmentally friendly and efficient protocol eliminates the use of chemical oxidants and facilitates the synthesis of the desired molecules. This approach offers an efficient and versatile method to synthesize quinones that exhibit cytotoxicity against cancer cell lines.     

Fractionated crystallization in blends of functionalized poly(tetrafluoroethylene) and polyamide

Blends of poly(tetrafluoroethylene)/polyamide (PTFE/PA) were prepared to combine the good processing properties of PA with the excellent sliding properties of PTFE. For the compatibilizing of the immiscible components the chemical reaction of functional groups of modified PTFE (micro powder produced by electron irradiation in air) and polar PA during a reactive extrusion process was used. The parameter influencing the efficiency of the in‐situ reaction between both components were varied. The crystallization and melting behaviour of the different blends was investigated by DSC. In dependence on the degree of compatibilization the phenomenon of fractionated crystallization of the dispersed PTFE component was observed. In this way a qualitative characterization of the dispersity of PTFE in dependence on the functionality of the components and the processing conditions is possible, and therefore an estimation of the efficiency of the in‐situ reaction.