Search

Infrared and heat shielding materials have a wide range of applications in military infrared invisibility and thermal insulation for energy saving, but mechanical damage during use may reduce the service life. In this study, waterborne polyurethanes/gallium tin oxide (WPU/GTO) composites with good infrared and thermal shielding capabilities were fabricated after the introduction of GTO nanoparticles into the thermal driven self-healing WPU matrix. The results showed that the WPU/GTO composite films can show good healing efficiency through thermally reversible DA reactions, with a self-healing efficiency of 80 % in 30 min at 120 °C. In addition, the presence of GTO gives the composite good thermal shielding properties without affecting its thermal stability. Due to free carrier absorption and plasma reflection, the resulting composite films containing 1 wt% GTO could shield from approximately 95 % of infrared light, with an insulation temperature difference of 15 °C when compared to pure polyurethane. This work provides a feasible solution for the preparation of infrared and heat shielding materials with self-healing capabilities. • VT-FTIR and TGA-FTIR joint testing system were used to analyze the self-healing mechanism and structures of polymer. • WPU-DA-GTO membranes presents excellent infrared shielding performance. • WPU-DA-GTO membranes also presents excellent self-healing performance. [ABSTRACT FROM AUTHOR]

Even though polyurethane (PU) has been widely applied, its superhydrophobicity is inadequate for certain applications. As such, the development of superhydrophobic polyurethane (SHPU) has recently attracted significant attention, with numerous motivating reports in recent years. However, a comprehensive review that summarizes these state-of-the-art developments remains lacking. Thus, this review aims to fill up this gap by reviewing the recent preparation methods for SHPU based on superhydrophobic theories and principles. Three main types of methods used in promoting the hydrophobicity of PU are emphasized in this review; (1) incorporation of silicide or fluoride to lower the surface energy, (2) creation of micro/nano-scale rough surfaces by electrospinning or grafting of nanoparticles, and (3) integrating the earlier two methods to develop a synergistic approach. Furthermore, this review also discussed the various applications of SHPU in oil spill treatment, protective coating, self-healing materials and sensors. [Display omitted] • The development of superhydrophobic polyurethane in recent years was reviewed. • The potential applications of superhydrophobic polyurethane were classified and illustrated. • The prospect of the development of superhydrophobic polyurethane was discussed. [ABSTRACT FROM AUTHOR]

The microphase separation of polyurethane is the result of thermodynamic incompatibility between the hard and soft segments, which plays a significant role in its micro structure and performance. In recent years, many researches about the microphase separation of polyurethane have been reported. However, there is a gap in summarizing the recent advances in the characterization methods and applications about it. To fill in this gap, this paper carefully compared and analyzed the characterization methods of the microphase separation such as Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), Dynamic thermomechanical analyzer (DMA), Atomic force microscopy (AFM), Transmission electron microscopy (TEM), and Small-angle X-ray scattering (SAXS). Moreover, applicaitions of the microphase separated polyurethane in shape memory, water resistance, and gas separation are also discussed in detail. • The paper systematically compared and analyzed the characterization methods of the polyurethane microphase separation. • Influences of the microphase separation on the physical properties are discussed in detail. • The relationship betwwen the microphase separation and hydrogen bond is summarized. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxane (POSS) functionalized with an amine group was designed and prepared. Then it was applied as a physical cross-linker to prepare waterborne thermoplastic polyurethane (WTPU)/POSS nanocomposite. Results revealed that the POSS had a little influence on the viscosity and storage stability of the WTPU/POSS dispersions. Moreover, the cured nanocomposite film with 8 wt% POSS showed superior surface hydrophobicity, the water contact angle was higher than 121° due to the migration of POSS on the surface, while the tensile strength increased up to 6.7 MPa and the elongation at break was higher than 800%. Dynamic thermomechanical analysis (DMA) results revealed a significant increase in the glass transition temperature (Tg) of the nanocomposite, the dielectric constant decreased from about 2.60 to 1.83. This POSS can made the polymer with excellent physical properties and low dielectric constant, which could be applied in integrated circuitry micro devices. Image 1 • Functionalized POSS with a single amine group was synthesized. • The WTPU containing functionalized POSS exhibited superior hydrophobicity and enhanced mechanical properties. • The WTPU/POSS films were still thermoplastic and possessed reprocessing ability and reusability. [ABSTRACT FROM AUTHOR]