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With the rapid economic development in recent years, there has been an increasing demand for durable and high-performance transportation road pavements. Polymer-modified asphalt has gained widespread acceptance due to its ability to enhance driving comfort and extend service life. Nevertheless, the longevity of asphalt pavements is often compromised by long-term traffic loads and harsh weather conditions, leading to cracking and degradation. To tackle this issue, dynamic chemistry introduces a promising solution for self-healing polymer-modified asphalt. By integrating dynamic bonds into the polymers structure, its network becomes adaptable to external triggers such as pressure, temperature, and pH, enabling material self-repair via dynamic healing mechanisms. This paper explores the synthesis methods and structural characteristics of dynamic self-healing polymers, their impact on the self-healing performance of modified asphalt and the classification of dynamic bonds. Additionally, the paper discusses methods for evaluating the self-healing performance and identifies future challenges and research directions for self-healing polymer-modified asphalt materials. [ABSTRACT FROM AUTHOR]

A series of novel network polymers P1-P6 and Pn-Znx:y based on metal–ligand coordination bonds with different strength were prepared by one pot method. The structures of the polymers were confirmed by NMR and FT-IR spectra. The amorphous structure of polymers was determined by X-ray diffraction analysis with only broad scattering peaks detected. The TGA and DSC showed that the increase of pyridyl group can dramatically improve the thermal stability of polymers, and Tg gradually decreases with the increase of pyridyl and pyridine groups. When the amount of Zn(II) increases, the thermal stability and the Tg gradually decreases. Optical microscope images indicated that the cross-linked network polymers Pn-Zn1:2 all had obvious self-healing properties at room temperature, and the 50% cross-linked network P3-Zn1:2 and P4-Zn1:2 with less pyridine content have better self-healing performance. Further exploration of the self-healing properties of P3-Znx:y by adjusting the molar ratio of dianhydride to Zn(II), P3-Zn1:4 has the best self-healing performance. [ABSTRACT FROM AUTHOR]

Self-healing polymer networks have attracted much attention because of the contribution to resource and energy savings by improving their service life. Herein, photo-polymerization reactions of α-cyclodextrin-glycidyl methacrylate adduct (αCD-GMA)/poly(ethylene glycol) methacrylate (PEGMA), β-cyclodextrin-glycidyl methacrylate adduct (βCD-GMA)/PEGMA, and αCD-GMA/3,4-dichlorophenyl isocyanate-end-capped PEGMA produced cyclodextrin/poly(ethylene glycol)-based network (CP, βCP, and DCP-CP, respectively) films. The thermal, mechanical, and self-healing properties of the CP films were compared with those of the βCP and DCP-CP films. The loss factor (tan δ) peak temperatures (− 9 to − 3 °C) measured via dynamic mechanical analysis (DMA), tensile strengths and moduli of the CP films decreased with increasing PEGMA content. Although all photo-polymerized films exhibited self-healing properties upon standing at room temperature for 24 h, the healing efficiencies in terms of tensile strength for the CP films were much higher than those for the βCP and DCP-CP films, in which the complexation of cyclodextrin-poly(ethylene glycol) (PEG) units is difficult. The CP film with the highest PEGMA fraction exhibited the highest healing efficiency and healed at least thrice. The 2D 1H–1H NOESY spectra of αCD-GMA/PEGMA and immersion of the self-healed CP film in PEG solutions suggested that the self-healing properties were imparted by reversible α-CD–PEG host–guest interactions. [ABSTRACT FROM AUTHOR]

Mixtures of tung oil (TO) and 4,4'-bismaleimidodiphenylmethane (BMI) in the molar ratios of 1:3 and 2:3 were cured at 100 °C or 160 °C to produce the cured products (TB13, TB23 or htTB13, htTB23). Fourier-transform infrared spectroscopy of the cured products confirmed that the trans, trans-diene moieties of TO are almost completely consumed for all the cured products; furthermore, the maleimide groups were almost completely consumed for all the cured products, except for TB13. Differential scanning calorimetry results of the cured products revealed that TB13 and TB23 exhibited strong endothermic peaks due to the retro-Diels–Alder (rDA) reaction. The rDA enthalpy change (ΔHrDA) of TB13 was higher than that of TB23, and the ΔHrDAs of htTB13 and htTB23 were considerably smaller than that of TB13 and TB23. The tan δ peak temperatures of the cured products measured by dynamic mechanical analysis were in the range of 55–131 °C and were increased in the order: TB23 < TB13 < htTB23 < htTB13. The 5% weight loss temperatures of all the cured products were higher than 400 °C. Although TB13 and TB23 exhibited self-healing properties upon hot-pressing at 100 and 120 °C, respectively, htTB13 and htTB23 exhibited no self-healing ability. [ABSTRACT FROM AUTHOR]

A new method was provided to synthesize Diels–Alder (DA) self-healing cross-linked polyamides (SH-cPAs) with high tensile strength and good self-healing efficiency. A furfurylamine-N,N'-bis(methyl propionate) (FA-BMP) was synthesized through the Michael addition of furfurylamine and methyl acrylate. Bulk polycondensation of FA-BMP with bis(2-aminopropyl) polypropylene glycol and m-xylylenediamine were conducted, and several polyamide prepolymers containing furan pendent groups (pFU-PAs) were synthesized. From a DA reaction between pFU-PAs and 1,5-bismaleimido-2-methylpentane, different SH-cPAs were prepared. The pFU-PAs were characterized by 1H NMR, 13C NMR, FT-IR, amine values, and size exclusion chromatography. The DA reaction in SH-cPAs were demonstrated by FT-IR and 1H NMR spectra. Their thermally repairing was verified with polarizing optical microscopy and tensile tests. SH-cPAs exhibits tensile strength up to 37 MPa with strain at break of 27%-164%. Their tensile strength after self-repairing was still up to 26 MPa with self-healing efficiency of 70%-92%. [ABSTRACT FROM AUTHOR]