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To interpret the diffusion behavior of oxygen in epoxy asphalt with different cross‐linking degrees, epoxy asphalt‐oxygen diffusion layer models were constructed. The effect of temperature on oxygen diffusion and the number of oxygen molecules penetrating the epoxy asphalt was quantitatively analyzed. Fick's second law was used to determine the oxygen diffusion coefficient. The Mean square displacement (MSD) was extracted to analyze the effect of cross‐linking degree on the molecular motion of the base asphalt. The results show that as the cross‐linking degree increases, the number of oxygen in the epoxy asphalt decreases, accompanied by a reduction in the oxygen diffusion coefficient. Temperature significantly affects the rate of oxygen diffusion, with higher temperatures leading to greater diffusion depths over the same simulation time. The oxygen diffusion coefficient of epoxy asphalt ranges from 4.60 × 10−11 to 2.20 × 10−10 m2/s at temperatures of 298–373 K. The epoxy system markedly restricts the movement of base asphalt molecules, with saturate being most affected by cross‐linking degree and asphaltene the least. A high cross‐linking network impedes the asphalt‐oxygen contact oxidation, enhancing epoxy asphalt's anti‐aging capacity. These findings provide support for optimizing epoxy asphalt formulations and guiding the development of anti‐oxidant epoxy asphalt. [ABSTRACT FROM AUTHOR]

This study aims to analyze the degradation behavior and mechanisms of amine-cured epoxy asphalt (EA) under the combined effects of ultraviolet (UV) radiation, oxygen, and temperature. To achieve this, amine-cured epoxy resin (ER) and EAs containing 35%, 45%, and 55% asphalt content were prepared and subjected to simulated UV-based aging. Various analytical techniques were employed to investigate the mechanical properties, microstructure, morphology, and oxidation layer of ER and EAs. The results indicate that after UV-based aging, ER and EAs with 35%–45% asphalt content experienced an increase in mass, a decrease in strength and glass transition temperature. In comparison, EAs with 55% asphalt content exhibited the opposite trends. The elongation and (Tanδ)max of ER and EAs reduced, whereas the storage modulus and hardness at mid to high temperatures rose. At the microstructural level, the degradation of the resin phase was confirmed by changes in ether, ester, and amide groups, whereas the generation of sulfoxide groups was associated with the oxidation of the asphalt phase. Compared with ER, the surface of EA has obvious defects after aging, which is the main reason for the decrease in contact angle. As the asphalt content increases, EAs exhibit higher carbonyl concentration, more profound oxidation, and more obvious performance degradation. This trend suggests that the resin phase mitigates the aging of the asphalt phase by absorbing harmful UV radiation and oxygen. [ABSTRACT FROM AUTHOR]

To study the effects of curing agent ratio, asphalt content, and crosslinking degree on the properties and distribution of epoxy asphalt with a compound system of dicarboxylic acid and acid anhydride, epoxy asphalt molecular models with two asphalt contents of 25% and 65% and three curing agent ratios of 10:1, 5:1 and 1:1 were constructed by Materials Studio. Various epoxy resin crosslinking degrees were further realised by Perl language crosslinking script. Glass transition temperatures were calculated to characterise low temperature flexibility. Energy systems and interaction energy were simulated to characterise the compatibility of epoxy asphalt. The radial distribution function (RDF) was calculated to observe the composition distribution of epoxy asphalt. The results show that the raise of the crosslinking degree and the proportion of anhydride curing agent increased the Tg of epoxy asphalt, impairing the low temperature performance. The increase in asphalt content was beneficial to the stability of the epoxy asphalt. Resin-based epoxy asphalt had stronger interaction between epoxy resin phase and asphalt phase, and the interaction energies both reached the maximum values at crosslinking degree of around 25%. Resin-based and asphalt-based epoxy asphalt had the most notable composition difference in the distribution of asphaltenes and acid anhydrides. [ABSTRACT FROM AUTHOR]

Zr-doped apatite-type lanthanum silicate La9.33 Si6 - x Zrx O6 (x = 0.00, 0.05, 0.10, 0.15, 0.20) (LSZO) was prepared by the urea-nitrate combustion method at 600 °C. The optimum sintering temperature was determined to be 1550 °C based on linear shrinkage, density and SEM morphology. The doping sites were identified using XPS and 1R characterization, and Zr4+ entered the lattice to replace some of the Si1 to form [Si(Zr)O4] tetrahedra. EIS tests show that Zr doping increased the conductivity of LSO, with undoped La9.33 Si6 O26 having a conductivity of 3.31 x 10-5 S/cm at 600 °C and La9.33 Si5.90 Zr0.10 O26 having the best conductivity of 8.79 x 10-4 S/cm. The activation energy decreased first and then increased with the increase of doping amount. XRD analysis showed that the doped crystal volume was larger than that of the undoped, and Zr doping expanded the interstitial oxygen conduction channel, so the conductivity enhancement mechanism of apatite-doped lanthanum silicate was the unit cell volume enhancement mechanism. When x ≥ 0.15, the excess Zr4+ combined with the interstitial oxygen inside the lattice to generate ZrO2, thereby blocking the transport of interstitial oxygen, and its activation energy increased and conductivity decreased relative to x = 0.10. [ABSTRACT FROM AUTHOR]

This research investigated the aging degradation of anhydride-cured epoxy asphalt (EA) subjected to ultraviolet (UV) exposure. A UV accelerated aging test was applied to age EA binders with graduated asphalt contents at 25%, 35%, 45%, 55%, and 65%. The effects of aging on the mechanical, chemical properties, and microstructure of EA were investigated. Results show that the more asphalt is introduced, the higher the mass loss rate of the EA binders, and the more prominent the decrease in elongation and fracture energy during aging. The storage modulus and hardness of EA binders increased after aging. The tensile strength and glass transition temperature of EA binder with 25%-45% asphalt content decreased, while those of EA binder with 55%-65% asphalt content increased. Besides, several carbonyl compounds formation, hydroperoxides formation, and loss of alkyl compounds were observed. Also, when the asphalt content was lower than 45%, holes and microcracks appeared on the surface, while above 45% asphalt content wrinkles. Degradation of the resin network in EA binders was evident by the loss of ester compounds and the microcrack of the resin phase. Overall, the resin network can reduce UV damage to asphalt and improve the photo-oxidative aging resistance of EA materials. [ABSTRACT FROM AUTHOR]

To study the influence of the cross‐linking network on the thermal oxygen aging performance of the epoxy asphalt, the laser copolymerization microscopy, Fourier transform infrared spectroscopy and element analysis tests were used to characterize the changes in chemical components of epoxy asphalt with composite curing system during thermal oxygen aging. According to the changes in chemical components, the epoxy asphalt molecular models were constructed. The diffusion behavior of oxygen atoms was analyzed, the aging degree was determined. Moreover, the Tg and radial distribution function were calculated to determine the effect of aging on the low‐temperature performance and component distribution of epoxy asphalt. The results show that a proper proportion of curing agent helped to uniform distribution of the asphalt phase. The rise in anhydride curing agent content increased the density of crosslinking network, limited the diffusion of oxygen atoms, and contributed to the resistance of epoxy asphalt chemical components to thermal oxygen aging. However, the high proportion of anhydride aggravated the oxidation reaction of the asphalt phase due to the uneven coating of the asphalt phase. After thermal oxygen aging, the distribution of asphaltene and epoxy resin phase showed a concomitant phenomenon due to polarity adsorption. [ABSTRACT FROM AUTHOR]

Mg77+xNi20−xLa3 (x = 0, 5, 10, 15) alloys were successfully prepared by the vacuum induction melting method. The structural characterizations of the alloys were performed by using X-ray diffraction and scanning electron microscope. The effects of nickel content on the microstructure and hydrogen storage kinetic of the as-cast alloys were investigated. The results showed that the alloys are composed of a primary phase of Mg2Ni, lamella eutectic composites of Mg + Mg2Ni, and some amount of LaMg12 and La2Mg17. Nickel addition significantly improved the hydrogen-absorption kinetic performance of the alloy. At 683 K, Mg77Ni20La3 alloy and Mg82Ni15La3 alloy underwent hydrogen absorption and desorption reactions for 2 h, respectively, and their hydrogen absorption and desorption capacities were 4.16 wt.% and 4.1 wt.%, and 4.92 wt.% and 4.69 wt.%, respectively. Using the Kissinger equation, it was calculated that the activation energy values of Mg77Ni20La3, Mg82Ni15La3, Mg87Ni10La3 and Mg92Ni5La3 alloys were in the range of 68.5~75.2 kJ/mol, much lower than 150~160 kJ/mol of MgH2. [ABSTRACT FROM AUTHOR]