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.

A thermoreversible cross-linked styrene–butadiene–styrene (SBS) based on Diels–Alder (DA) chemistry was fabricated via a solvent-free melt processing approach. Maleated SBS was adopted so that furfurylamine could be grafted onto pendant anhydride groups to introduce furan moieties. Functionalized SBS was then cross-linked with bismaleimide through DA coupling. Thermoreversibility and network dynamics of the DA-crosslinked SBS (DSBS) were characterized by FTIR spectroscopy, solubility assessment, DSC analysis, and tensile testing. FTIR spectroscopy results verified the successful furfurylamine grafting and DA cross-linking mediated by bismaleimide in the DSBS. The DSBS exhibited enhanced solvent resistance, thermal stability and mechanical performance. The Diels–Alder (DA) linkages within the DSBS network undergo thermally induced dissociation at elevated temperatures (>140 °C) and readily reform at 110 °C, thereby enabling reversible and repeatable network reconstruction. Furthermore, the mechanical properties of DSBS can be systematically tailored by varying the bismaleimide content. Specifically, increasing the bismaleimide concentration results in enhanced ultimate tensile strength and elastic modulus, accompanied by a reduction in ductility. These findings demonstrate an efficient, cost-effective, and environmentally sustainable approach for the fabrication of high-performance, recyclable SBS elastomers.

A thermoreversible dynamic covalent network was constructed in recycled polyethylene terephthalate (RPET) via Diels–Alder (DA) chemistry to enhance mechanical performance, reprocessability, and self-healing. Furan-functionalized RPET (RPET-3F) was first prepared from maleated RPET (RPET-MA), followed by crosslinking with bismaleimide (BMI) at different feed ratios. FTIR spectra confirmed the successful grafting of furan groups and the formation of DA adducts. With increasing BMI content, the gel fraction and crosslink density increased substantially, whereas the swelling ratio decreased, indicating the progressive development of a three-dimensional network. RPET-3F-2B showed the highest network integrity among all samples. DSC analysis revealed a distinct retro-DA dissociation peak at 143 °C and a recrosslinking peak near 124 °C, confirming the thermal reversibility of the DA network. Owing to the optimized network structure, RPET-3F-2B exhibited the best mechanical properties and excellent reprocessability, retaining stable performance after three hot-pressing cycles. After repeated reprocessing, its tensile strength remained 74% higher than that of RPET-MA, while the elongation at break was still improved by about 10%. Moreover, the sample showed efficient thermally induced self-healing at 150 °C, with surface cracks nearly disappearing after 4 h. These results demonstrate that DA chemistry offers a promising route to the high-value reutilization of RPET into recyclable, multifunctional polymer materials.