Comparative study of the effects of anatase and rutile titanium dioxide nanoparticles on the structure and properties of waterborne polyurethane

Surface Modification and Properties of Thin Ink Films with Added TiO2 and ZnO Nanoparticles Applied on Paperboard Substrates

In this study, the surface modification of thin ink films with added nanoparticles was used to improve the functional properties of ink applied on paperboard substrates. The surface modification was performed by additional exposure of the samples to xenon radiation. Anatase TiO₂, rutile TiO₂ and ZnO were added to the base ink. The effect of surface modification on the surface, structural, and mechanical properties of the printed ink films was determined by FTIR-ATR spectroscopy, calculating the surface free energy and adhesion parameters, performing the rub resistance test of the printed samples, and by measuring the resistance to bending. Color measurements on the ink films were performed in order to observe the optical properties of unmodified and modified samples. The results showed that surface modification significantly improved the adhesion properties of the thin ink films and the mechanical properties of the samples. The results obtained on uncoated and coated paperboard showed that the addition of rutile TiO₂ and ZnO nanoparticles had the greatest effect on the rub resistance of the ink films. The results of the color analysis showed that the addition of nanoparticles did not change the optical properties of the modified ink films and that rutile TiO₂ and ZnO nanoparticles improved the lightfastness of the applied ink films.

Eco-friendly functional two-component flame-retardant waterborne polyurethane coatings: a review

Green functional two-component flame-retardant waterborne polyurethane (2K-FWPU) coatings possess outstanding green traits, such as providing eco-friendly protection, having low toxicity, and generating no pollution.

Improvement of Mechanical Properties and Self-Healing Efficiency by Ex-Situ Incorporation of TiO2 Nanoparticles to a Waterborne Poly(Urethane-Urea)

This research work was focused on the incorporation of TiO₂ nanoparticles into synthesized solvent-free waterborne poly(urethane-urea) (WPUU) based on hydrophilic poly(ethylene oxide) (PU0) in order to improve both the mechanical properties and self-healing effectiveness of a polymer matrix. The incorporation of TiO₂ nanoparticles resulted in a successful enhancement of the mechanical properties of nanocomposite films when compared to PU0. Simultaneously, the obtained nanocomposite films did not only maintain the self-healing ability of the PU0 film, measured by means of mechanical properties after successive cutting/recovery cycles, but they also showed a higher self-healing efficiency than the PU0 film. Moreover, the well-dispersed TiO₂ nanoparticles, visualized by atomic force microscopy (AFM), kept their conductive properties when embedded in the PU0 matrix, as was confirmed by electrostatic force microscopy (EFM). This research work described a simple and industrially appealing way to control the dispersion of commercially available TiO₂ nanoparticles in waterborne poly(urethane-urea) for the designing of inorganic/organic hybrid nanocomposites with enhanced mechanical properties and self-healing efficiency, in which TiO₂ nanoparticles preserved their conductive properties within the polymer matrix.

The effect of silica thickness on nano TiO2 particles for functional polyurethane nanocomposites

In order to help reduce the agglomeration of TiO₂ nanoparticles in polyurethane coatings while enhancing their photoactivity and mechanical/physical properties, this work examined encapsulating TiO₂ nanoparticles in a thin layer of SiO₂, prior to their nanocomposite polymerization. By applying a Stöber process, varying thicknesses of SiO₂ were successfully coated onto the surface of anatase and rutile TiO₂ nanoparticles. The methylene blue results showed that different loadings of SiO₂ onto the TiO₂ surface significantly influenced their photocatalytic activity. When the loading weight of SiO₂ was lower than 3.25 wt%, the photocatalytic activity was enhanced, while with higher loadings, it gave lower photocatalytic activity. When the rutile phase TiO₂ surface was fully covered with SiO₂, an enhanced photocatalytic activity was observed. When these silica coated nanoparticles were applied in polyurethane coatings, increasing the amount of SiO₂ on the titania surface increased the coatings contact angle from 75° to 87° for anatase phase and 70°-78° for rutile phase. The Young's modulus was also increased from 1.06 GPa to 2.77 GMPa for anatase phase and 1.06-2.17 GPa for rutile phase, attributed to the silica layer giving better integration. The thermal conductivity of the polyurethane coatings was also successfully decreased by encapsulating SiO₂ on the titania surface for next generation high performance coatings.

Molecular weight effects of PEG on the crystal structure and photocatalytic activities of PEG-capped TiO2 nanoparticles

The increasing molecular weight of PEG can increase the water dispersion but decrease the photocatalytic activity of PEG-capped TiO₂.