Novel waterborne poly(urethane‐urea)/silica nanocomposites
Abstract
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The effect of TiO 2 particles on thermal properties of polycarbonate-based polyurethane nanocomposite films
In this work, aliphatic starting reactants were used to prepare a series of polycarbonate-based polyurethane (PC-PU) nanocomposite films with a low amount of titanium dioxide (TiO2) nanoparticles (0.5, 1.0 and 2.0%) by one-step technique. The influence of nanoparticles on the structure and hydrogen bonding, as well as the microphase and topography of the obtained hybrid materials was followed by Fourier transform infrared spectroscopy, Atomic force microscopy and Scanning electron microscopy cou...
Thermoplastic polyurethane elastomers (TPUs) containing aliphatic polycarbonate soft segments and hard segments formed by 1,1′-methanediylbis(4-isocyanatocyclohexane) or 1,6-diisocyanatohexane and a combination of two chain extenders, i.e., 2,2′-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol and 3-hydroxy-2-(hydroxymethyl)-2-methylpropanoic acid (DMPA), were synthesized in a one-step catalyzed melt polyaddition process. The obtained colorless, transparent and high-molar-mass materials, which dif...
Hierarchically porous SiO2/polyurethane foam composites towards excellent thermal insulating, flame-retardant and smoke-suppressant performances
Abstract Polyurethane foam (PUF) is widely used in building insulation field but highly flammable. In an effort to develop an efficient way to reduce flammability and smoke release of PUF without sacrificing its inherent merits, a novel strategy has been proposed to decorate silica aerogels onto the surface of PUF to fabricate hierarchically porous SiO2/PUF composites. Due to the unique hierarchically porous structure, the resultant composites showed superior thermal insulation with a lower ther...
Functional properties of films based on novel waterborne polyurethane dispersions prepared without a chain-extension step
Abstract A series of novel waterborne polyurethane (PU) dispersions was prepared from a polycarbonate-based macrodiol, 1,6-diisocyanatohexane, 2,2-bis(hydroxymethyl) propionic acid (DMPA) and triethylamine. Different macrodiol-to-DMPA (diol) ratios and different excesses of isocyanate were used, and the typically used chain-extension step was omitted. Systematic measurements of the particle size revealed that PU particles have diameters lower than 100 nm at diol ratios of 1:1 and 1:2, while a di...
Formation of linear and crosslinked polyurethane nanoparticles that self-assemble differently in acetone and in water
For the first time, stable water-borne polyurethane dispersions (PUDs) leading to mechanically strong polyurethane (PU) coatings were prepared without any chain extender. Elimination of this step and using of water-crosslinking gives promising applications of PUDs as biomaterials and production on an industrial scale. The PU system consists of polycarbonate macrodiol (PCD), (2,2-bis(hydroxymethyl)) propionic acid (DMPA), 1,6-diisocyanatohexane (HDI) and N,N-diethylethanamine (TEA). Fourier trans...
Nanocomposites made from thermoplastic waterborne polyurethane and colloidal silica. The influence of nanosilica type and amount on the functional properties
Abstract Novel waterborne polyurethane/silica nanocomposites were prepared via blending of two aqueous dispersions. Polyurethane water dispersion (PUD) was synthesized from polycarbonate diol (PC), 1,6-diisocyanatohexane (HDI) and butane-1,4-diol (BD) in order to provide solely linear character of PU chain. Two types of commercial colloidal silica, Ludox AS and Ludox TMA, differing in the size, shape and type of counter ions were used. The nanocomposites were made from negatively charged PUD and...
Organic–inorganic nanocomposite films made from polyurethane dispersions and colloidal silica particles
AbstractPolyurethane/silica nanocomposites were prepared by solution blending of polyurethane water dispersion (PUD) based on polycarbonate macrodiol with colloidal silica aqueous sol LUDOX TMA. Because of mixing PUDs made from linear polyurethane with the nanofiller, only physical polymer/filler type of interface formed by hydrogen bonds was obtained. As a result the materials were possible to reuse after dissolution in acetone followed by dispersion in water. The effect of colloidal silica con...
Preparation and characterization of thermoplastic water-borne polycarbonate-based polyurethane dispersions and cast films
Stable water-borne polyurethane dispersions (PUDs) were prepared from bifunctional aliphatic polycarbonate-based macrodiol, 2,2-bis(hydroxymethyl)propionic acid (DMPA), 1,6-diisocyanatohexane, 1,4-butanediol (BD), and triethylamine. Water-borne dispersion particles are thus solely formed from self-assembled linear PU chains. Both PUDs and PUD-based films were characterized with regards to the concentration of DMPA (ionic species content) and BD (hard-segment content). Average particle size of PU...