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Abstract: The physico-chemical properties of three grafted pullulans (P) having linked poly(3-acrylamidopropyl)trimethylammonium chloride (pAPTAC) as side chains (P-g-pAPTAC1, P-g-pAPTAC2 and P-g-pAPTAC3 with 22.53, 29.05, and 34.51 (wt.%) of pAPTAC content in polymer, respectively) and possessing polyelectrolyte character were determined by light scattering analysis. All grafted pullulan aqueous solutions were tested in the presence of 0.5M NaCl, KCl, NaNO3 or KNO3. The biggest associations were recorded in 0.5M NaCl aqueous solutions for P-g-pAPTAC1, P-g-pAPTAC2 and P-g-pAPTAC3 according to the maximum values for Rg extracted from MALLS (multiangle laser light scattering) measurements. Also, the dominant conformation in salted solution of these polyelectrolytes was random coil as Debye plot analysis revealed. Antibacterial activity was tested by Kirby–Bauer diffusion method and all grafted pullulans dissolved in aqueous solutions of 0.5M NaCl have developed inhibition zone against Staphylococcus aureus (ATCC 25923). [Copyright &y& Elsevier]

The thermotropic and optical characterisations of a novel polymer dispersed liquid crystal (PDLC) system based on polysulfone UDEL P-1700 as polymer matrix and a low molecular weight liquid crystal compound containing a mesogenic azomethine core and a cyano-substituent were investigated. The PDLC samples were prepared by solvent-induced phase separation (SIPS) and thermally induced phase separation (TIPS) methods using various compositions in the two components. Information on the morphology and phase structure was obtained by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction measurements. PDLC systems with well-defined droplets were obtained for the composite with medium content of liquid crystal compound. The optical characterisation of these materials was performed by analysing their UV-visible absorption and photoluminescence emission as a function of the liquid crystal aggregation degree. [ABSTRACT FROM AUTHOR]

Abstract: A new poly(azomethine-ether) was synthesized by the reaction of bisphenol A with a thermotropic azomethine monomer, namely 4,4′-oxy-bis(4-chlorobenzylideneimino phenylene). In order to understand the influence of the molecular weight on the thermal properties, four fractions were isolated from the initial polymer. They were investigated by elemental analysis and spectroscopic methods (IR, UV, 1H NMR) and their thermal behaviour was studied by differential scanning calorimetry, optical microscopy, thermogravimetrical analysis. An increase of the thermal transition temperatures and mesophase order with increasing molecular weight was noticed. [Copyright &y& Elsevier]