104,758 research outputs found
Synthesis, characterisation and properties of aramid copolymers prepared from AB and AB2 monomers
No full textThe 1H and 13C NMR Spectra of a Hyperbranched Aromatic Polyamide from p-Phenylenediamine and Trimesic acid
No full textNMR Studies on a Hyperbranched Aromatic Polyamide from A2 and B3 Monomers: Structure and Interactions with Lithium Salts
No full textSynthesis, characterisation and properties of aramid copolymers prepared from AB and AB2 monomers
No full textPreparation and Characterisation of Pd Nanoclusters in Hyperbranched Aramid Templates to be used in Homogeneous Catalysis
No full textIndacenodithiophene Homopolymers via Direct Arylation: Direct Polycondensation versus Polymer Analogous Reaction Pathways
No full textIndacenodithiophene (IDT)-based materials are emerging high-performance conjugated polymers for use in efficient organic photovoltaics and transistors. However, their preparation generally suffers from long reaction sequences and is often accomplished using disadvantageous Stille couplings. Herein, we present detailed synthesis pathways to IDT homopolymers using C-H activation for all C-C coupling steps. Polyketones are first prepared by direct arylation polycondensation (DAP) in quantitative yield and further cyclized polymer analogously. This protocol is suitable for obtaining structurally well-defined IDT homopolymers, provided that the conditions for cyclization are chosen appropriately and that side reactions are suppressed. Moreover, this polymer analogous pathway gives rise to asymmetric side-chain patterns, which allows one to fine-tune physical properties. Alternatively, IDT homopolymers can be obtained via oxidative direct arylation polycondensation of IDT monomers (oxDAP), leading to IDT homopolymers with similar properties but at reduced yield. Detailed characterization by NMR, IR, UV-vis, and PL spectroscopy, and thermal properties, is used to guide synthesis and to explain varying field-effect transistor hole mobilities in the range of 10(-6)-10(-3) cm(2)/(V s)
Preparazione, caratterizzazione e proprietà di arammidi iper-ramificate a partire da reagenti di tipo A2 + B3
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Dendritic aromatic polyamides. New polymeric materials for high performance applications
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