In this work, eco-friendly superhydrophobic coatings were prepared by dispersing hydrophobic silica nanoparticles and a waterborne silicone-modified polyurethane dispersion into an ethanol solution, which was free of fluorine and volatile toxic solvents. The effects of the silica content on the hydrophobicity and scratch resistance of the hydrophobic surfaces were investigated by WCA measurements and a sandpaper abrasion test, respectively. The experimental results indicated that when the silica content exceeded 30% by mass, the silica/silicone-modified polyurethane coatings had superhydrophobicity. Meanwhile, the superhydrophobic coatings with a silica content of 30% by mass simultaneously had the optimal mechanical stability. We studied the morphology and roughness of the hydrophobic surfaces with different silica content and attempted to briefly explain the influence mechanism of silica content. Furthermore, anti-icing and oil–water separation experiments were carried out on the superhydrophobic coatings, which exhibited good anti-icing performance and high separation efficiency. The eco-friendly superhydrophobic coating is expected to be applied in the fields of oil–water separation, anti-icing, and self-cleaning, etc.
7 January 2021 in Journal of Applied Polymer Science
Emulsified asphalt is widely used for pavement maintenance due to its ease of application. However, its use is limited by poor high-temperature stability and low bonding strength. This study attempted to prepare a self-crosslinking waterborne acrylate (SWA)-type admixture using a diacetone acrylamide (DAAM)-adipic dihydrazide (ADH) crosslinking system and applied it to emulsified asphalt to ultimately obtain self-crosslinking waterborne acrylate-modified emulsified asphalt (AMEA). The research explored the effects of SWA on the fundamental properties, rheological characteristics, microscopic morphology, and bonding performance of AMEA. Results indicated that SWA undergoes self-crosslinking reactions during the demulsification process, forming a continuous and stable network structure that significantly enhances the strength of emulsified asphalt while improving softening point and high-temperature stability. Rheological analysis revealed that within the 10–15 phr dosage range, the influence of frequency on emulsified asphalt was minimized, with notable improvements in high-temperature elastic recovery and deformation resistance. Particularly when the dosage exceeds 10 phr, the material demonstrates adaptability to high-traffic environments. Pull-off tests demonstrated that SWA can increase the interlayer bonding strength of emulsified asphalt by over 50%. However, SWA exhibits some negative impact on the low-temperature ductility of emulsified asphalt, necessitating cautious dosage control during application. This novel self-crosslinking waterborne acrylate-modified emulsified asphalt, with its excellent bonding performance and superior high-temperature stability, emerges as a crucial material choice for pavement preventive maintenance.
The formation of recyclable polyethylene materials is significantly limited by traditional crosslinking methods, which involve solvent-heavy processes and permanent chemical bonds that cannot be undone. Herein, we report an environmentally friendly and scalable approach to construct a thermo-reversible polyethylene network (PE-g-DA) via solvent-free, one-step melt processing based on furan–maleimide Diels–Alder (D–A) dynamic covalent chemistry. Furan-functionalized polyethylene was dynamically crosslinked with bismaleimide during melt mixing, fully compatible with conventional polyolefin processing techniques. FTIR spectroscopy, temperature-dependent solubility, and differential scanning calorimetry collectively confirm the reversible formation and dissociation of D–A adducts, enabling thermal switching of the network structure. Equilibrium swelling experiments based on the Flory–Rehner model indicate that the crosslink density can be precisely controlled by varying the bismaleimide content. As a result, PE-g-DA exhibits significantly enhanced tensile strength while maintaining high ductility at moderate crosslink densities. Notably, the dynamic network allows efficient thermal reprocessing, with recycled samples retaining approximately 93% and 80% of their original tensile strength after the first and second reprocessing cycles, respectively. Moreover, intrinsic thermal self-healing behavior is directly visualized by scanning electron microscopy at 120 °C. This work demonstrates that combining dynamic Diels–Alder chemistry with solvent-free melt processing offers a practical and sustainable route to recyclable, reprocessable, and self-healable polyethylene materials with clear potential for large-scale industrial production.