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In this study, a series of polyurethane (PU) films based on three different type of chain extenders including glycerol, sodium alginate (SA) and nanocomposite of tetrasodium thiacalix[4]arene tetrasulfonate-sodium alginate (TS-SA) were synthesized. The effect of SA and TS-SA chain extenders on different properties of the PU films were studied using FTIR, XRD, DSC, TGA, SEM, AFM, and tensile analysis and the obtained results were compared with the polyurethane film extended with glycerol. The TGA and tensile studies confirmed that incorporation of TS-SA into the polyurethane backbone provide the superior thermal and mechanical properties compared to SA. Moreover, the influence of the SA and TS-SA chain extenders on hydrophilicity of the prepared films was also investigated by contact angle measurement. The results showed that the hydrophilicity of PU/TS-SA is higher than the PU/Gly and PU/SA samples. In comparison with PU/Gly and PU/SA samples, the PU/TS-SA sample showed significant performance in water desalination via reverse osmosis technique due to its favorable porosity and improved hydrophilicity. The AFM analysis confirmed that the PU/TS-SA sample has the highest surface rouphness which cause an increase in the flux and anti-fouling property of this sample. Therefore, PU/TS-SA sample can be introduced as an efficient membrane for water desalination with enhanced thermal stability, mechanical properties, high salt rejection and water permeability., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Novel mechanically reinforced nanocomposite hydrogels (NCHs) were developed based on methacrylated gellan gum (MGG) and cationic polyurethane nanoparticles (CPUNs) through a green chemical approach. A series of NCHs were synthesized by the incorporation of CPUNs with weight ratios of 0, 10, 30 and 50 w/w% into the MGG solution, with two different methacrylation degrees (1.2, 5.6%). The chemical structure, morphology, mechanical properties, stimuli-responsivity and cytotoxicity of synthesized NCHs were investigated. Analysis of the hydrogels mechanical testing demonstrated that the addition of CPUNs affords the significant increase in compressive properties. Meanwhile, the formulation of NCH containing the MGG with lower methacrylation degree and 30 w/w% CPUNs showed the highest mechanical properties. Furthermore, equilibrium swelling ratio of the hydrogels decreased by CPUNs addition. Finally, it is worth mentioning that NCHs showed no significant toxicity to human dermal fibroblast cells (HDFs) which idealize them as the suitable hydrogels for biomedical applications., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The novel soluble alginate-based polyurethanes in organic solvents were synthesized by the reaction of NCO-terminated prepolymers and tributylammonium alginate (TBA-Alg) for the first time. The chemical structures of synthesized polyurethanes were characterized using FTIR, (1)H NMR and TGA. The reaction completion was confirmed by disappearing of NCO band in FTIR spectra. Furthermore, a peak at 4.71 ppm and some small peaks at a range of 4.12-4.37 ppm in the (1)H NMR of alginate-based polyurethanes were assigned to the backbone of alginate. The results of both FTIR and (1)H NMR were remarkably confirmed by TGA data. The ionic nature of polyurethane backbone not only affects on thermal properties of samples, but it also changes the chemically-bonded alginate morphology. Both polyether and polyester based non-ionic polyurethanes extended by TBA-Alg illustrated the distinct alginate, whereas those ionomers extended by alginate were appeared as the continuous systems at nanoscale., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Highly stretchable elastomeric samples based on cationic polyurethane dispersions-sodium alginate nanoparticles (CPUD/SA) were prepared by the solution blending of sodium alginate and aqueous polyurethane dispersions. CPUDs were synthesized by step growth polymerization technique using N-methyldiethanolamine (MDEA) as a source of cationic emulsifier. The chemical structure and thermal-mechanical properties of these systems were characterized using FTIR and DMTA, respectively. The presence of nanoalginate particles including nanobead and nanorod particles were proved by SEM and EDX. It was observed that thermal properties of composites increased with increasing SA content. All prepared samples were known as thermoplastic-elastomers with high percentages of elongation. Excellent compatibility of prepared nanocomposites was proved by the DMTA data., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A series of aqueous polyurethane dispersions were synthesized by the reaction of polytetramethylene glycol and isophorone diisocyanate, extended with dimethylol propionic acid. Their chemical structures were characterized using FTIR, (1)H NMR, and (13)C NMR, and thermal properties were determined by DMTA. Then, a number of aqueous polyurethane dispersions-sodium alginate (PUD/SA) compositions were prepared by addition of sodium alginate solution with different concentrations into the aqueous polyurethane dispersion. Characterization of chemical structure and thermal properties of these blends were performed by FTIR, EDX and DMTA, respectively. The morphology of the alginate in polyurethane matrix was studied by SEM. The hydrophilicity of the prepared samples decreases by increasing the content of sodium alginate in blends. These observations were attributed to the increase of hydrophilicity of the blends as a consequence of addition of hydrophilic carboxylate, hydroxyl and ether functional groups of the alginate to them., (Copyright © 2012 Elsevier Ltd. All rights reserved.)