High production costs and poor storage stability have become important constraints in the manufacture of modified asphalt binder. To simplify the production process and reduce the production cost, ...amorphous poly alpha olefin (APAO) and polyphosphoric acid (PPA) were applied to prepare highly stable modified asphalt binder. The influence of APAO/PPA on the temperature sensitivity, rheological property, storage stability, compatibility and microstructure of neat binder were studied by rotational viscosity (RV), dynamic shear rheometer (DSR), bending beam rheometer (BBR) and Fourier transform infrared (FTIR) spectroscopy. The results show that the incorporation of APAO/PPA reduced the temperature sensitivity of neat binder. The combined effect of APAO/PPA contributed to the improvement in deformation resistance, which was evidenced by the increase in failure temperature and percent recovery. However, the compound modification of APAO/PPA decreased the binder’s low-temperature performance. APAO strengthened the fatigue resistance of the binder, while PPA reduced the anti-fatigue performance. Composite modified asphalt binder with superior storage stability could be prepared, which was confirmed by the desired Cole–Cole plots and fluorescence imaging. Furthermore, chemical and physical reactions occurred during the APAO/PPA modification process. Overall, 2 wt.% (weight percentage) APAO and 1.5 wt.% PPA are recommended for the production of modified asphalt binder with remarkable rheological performance and storage stability.
Oil sands de-oiled asphalt (OSDOA) has become a bottleneck for refineries due to its enormous production and huge landfill costs. Applying OSDOA as a modifier is an effective way to reduce ...environmental pollution and disposal cost. In this study, the influences of OSDOA and polyphosphoric acid (PPA) compound modification on styrene-butadiene-styrene (SBS)-modified binder were investigated. The high-temperature rutting resistance, low-temperature anti-crack performance and fatigue resistance were obtained by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) test. Storage stability and microstructure were also investigated by storage test and Fourier-transform infrared (FTIR) spectroscopy. The results demonstrated that the compound modification of OSDOA/PPA dramatically enhanced the deformation resistance of SBS-modified binder and reduced its low-temperature cracking resistance. The anti-fatigue performance was also decreased. Moreover, the combined effect of OSDOA and PPA could produce composite modified asphalt with excellent storage stability, which was verified by desirable fluorescence images. Furthermore, both physical and chemical interactions coexisted during the OSDOA/PPA compound modification process. Consequently, the optimal doses of OSDOA and PPA were determined to be 10 wt% and 1.0 wt%, considering of the balance between high- and low-temperature characteristics and storage stability of composite modified asphalt.
The broadband light‐absorption ability of carbon dots (CDs) has inspired their application in photocatalysis, however this has been impeded by poor electron transfer inside the CDs. Herein, we report ...the preparation of Cu–N‐doped CDs (Cu‐CDs) and investigate both the doping‐promoted electron transfer and the performance of the CDs in photooxidation reactions. The Cu–N doping was achieved through a one‐step pyrolytic synthesis of CDs with Na2Cu(EDTA) as precursor. As confirmed by ESR, FTIR, and X‐ray photoelectron spectroscopies, the Cu species chelates with the carbon matrix through Cu–N complexes. As a result of the Cu–N doping, the electron‐accepting and ‐donating abilities were enhanced 2.5 and 1.5 times, and the electric conductivity was also increased to 171.8 μs cm−1. As a result of these enhanced properties, the photocatalytic efficiency of CDs in the photooxidation reaction of 1,4‐dihydro‐2,6‐dimethylpyridine‐3,5‐dicarboxylate is improved 3.5‐fold after CD doping.
Doped dots: Cu–N‐doped carbon dots (Cu‐CDs) were fabricated by a one‐step pyrolytic synthesis using Na2Cu(EDTA) as the precursor. Cu–N dopants concomitantly boost the conductivity and the electron‐accepting and ‐donating abilities of the CDs, enhancing the electron‐transfer process in the photooxidation of 1,4‐dihydro‐2,6‐dimethylpyridine‐3,5‐dicarboxylate (see picture; H yellow, N blue, C light blue, O red).
A styrene-butadiene-styrene (SBS) latex modifier can be used for asphalt modification due to the fact of its energy-saving, construction convenience, and economic advantages. The objective of this ...study was to investigate the influence of asphalt type and SBS latex dosage on the rheological properties, compatibility, and storage stability of asphalt through temperature and frequency sweep, steady-state flow, multiple stress creep and recovery (MSCR) tests, Cole-Cole plots and thermal storage tests. The results indicated that high SBS latex content is beneficial for improving anti-rutting, anti-fatigue, viscous flow resistance, and elastic recovery abilities of modified asphalt. The chemical composition of asphalt had a significant effect on the properties of the SBS latex-modified asphalt. High asphaltenes and low resins were favorable to enhancing anti-rutting and recovery properties but weakened the anti-fatigue, compatibility, and storage stability of modified asphalt. Furthermore, compared to SBS particle-modified asphalt, SBS latex-modified asphalt had greater rutting and fatigue resistance. However, SBS latex-modified asphalt had some disadvantages in compatibility and storage stability. Comprehensively considering the balance of viscoelastic properties, compatibility, and storage stability of SBS latex-modified asphalt, the mixing dosage of SBS latex modifier is recommended at 4.0 wt% which could feasibly replace SBS particle in asphalt modification.
Cashmere quality represents a crucial economic trait in cashmere goats. Investigating methods to enhance cashmere yield and quality is essential for the sustainable development of the cashmere ...industry. Although melatonin (MT) has been shown to promote cashmere wool growth, the underlying molecular mechanisms, particularly those involving melatonin-mediated long non-coding RNA (lncRNA), remain poorly understood. In this study, cashmere growth-related lncRNA (LncRNA MTC) was used as the starting point. LncRNA MTC overexpression and interference lentivirus vectors were constructed and transfected into Liaoning cashmere goat skin fibroblasts. Results from the cholecystokinin-octapeptide (CCK-8) assay demonstrated that LncRNA MTC overexpression significantly enhanced cell proliferation, while LncRNA MTC interference notably suppressed it. RNA pull-down coupled with mass spectrometry revealed a significant increase in LncRNA MTC’s binding to glutathione S-transferase M1 (GSTM1) in Liaoning cashmere goat skin fibroblasts following melatonin treatment. RNA immunoprecipitation (RIP) technology confirmed that the intracellular GSTM1 protein indeed interacts with LncRNA MTC. CCK-8 results showed that interference with GSTM1 could reverse the promotion of MT on the proliferation of skin fibroblasts of Liaoning cashmere goats. Co-immunoprecipitation (Co-IP) results demonstrated an association between GSTM1 and apoptosis signal-regulating kinase 1 (ASK1) proteins in Liaoning cashmere goat skin fibroblasts. The findings indicate that melatonin-mediated LncRNA MTC, which is related to cashmere growth, binds to the GSTM1 protein. This interaction affects the GSTM1-ASK1 protein complex formation, consequently inhibiting the apoptosis of Liaoning cashmere goat skin fibroblasts.
This research studies the effects of SBS copolymer and asphalt compositions on the properties of CR/SBS modified asphalts prepared by the terminal blend (TB) method. These CR/SBS modified asphalts, ...also called TB binders, were prepared by blending 20 wt% CR powders with two base asphalts and various amounts of SBS copolymers. The samples were subjected to conventional, rheological, force-ductility, rotational viscosity, thermal storage, and fluorescence microscopy tests. The results show that TB rubberized binders have superior properties to unmodified asphalts. The properties of TB rubberized asphalts were further improved by adding SBS copolymers, indicating that this is a feasible way to produce high-performance binders. However, the extent of improvement induced by SBS copolymer addition was less than that induced by CR addition. Activation energy (Ea) results suggest that this may be because the SBS copolymers do not form a polymer network structure throughout the asphalt. Moreover, the properties of TB binders are also affected by the asphalt composition. In terms of their stability index (SI) values, TB binders with various SBS contents showed good storage stability. Fluorescence observations revealed the state of rubber and SBS copolymer dispersion in the asphalt matrix, providing an explanation for the improved storage stability and confirming the deductions drawn from the Ea data. In conclusion, TB asphalt technology combined with SBS modification shows great potential to produce high-performance and cost-effective asphalt binders.
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●Time-temperature superposition principle holds for TB binders.●Rubbers contribute more to the properties of TB binders than SBS copolymers.●Chemical composition of base asphalt is crucial for TB binders.●The features of dispersed rubbers and SBS copolymers in asphalt are revealed.●TB rubberized asphalt technology combined with SBS modification is promising.
► BmimIm was applied in the transesterification of vegetable oils with methanol. ► BmimIm exhibited high activity under mild reaction conditions. ► The catalytic performance of BmimIm remained ...excellent after reused many times. ► An increase in unsaturation of biodiesel leads to a higher lubrication performance.
Preparation of biodiesel from vegetable oils, such as rapeseed oil, soybean oil and sunflower oil, catalyzed by an alkaline ionic liquid 1-butyl-3-methylimidazolium imidazolide (BmimIm) was investigated in this work. The results demonstrated that BmimIm exhibited high activity and the yield of biodiesel was up to 95% or more when molar ratio of methanol to vegetable oil was 6:1, ionic liquid dosage was 6wt.%, reaction temperature was 60°C, and reaction time was 60min. After BmimIm was used for the sixth time, the yield of biodiesel still remained at about 95%. The effects of the biodiesels on the lubricity of low-sulfur diesel fuel were also investigated using the High Frequency Reciprocating Rig method, and the results showed that sunflower biodiesel and soybean biodiesel had higher lubrication performance than that of rapeseed biodiesel.
The morphological characteristics of mineral filler particles, such as contour shape, angularity and surface texture, are closely related to their mineralogy and size and the crushing process used. ...In the present study, the importance and effects of particle mineralogy and size on the morphology of different mineral fillers were examined. A total of 12 mineral filler fractions were prepared using the same grinding process and sieving method, and analyzed by digital imaging. Six parameters were used to describe the 2-dimensional characteristics of mineral filler particles based on digital image processing. The sensitivity of these parameters was analyzed by correlation and analysis of variance methods. The results show that for mineral fillers of the same particle mineralogy, as the particle size decreases, the contour shape becomes more regular and the angularity and surface texture becomes less abundant. For mineral fillers of the same particle size, the granite filler particles have a more regular contour shape and richer angularity and surface texture than the limestone and basalt filler particles. The form factor, angularity parameter AI1 and fractal dimension can best reflect the sensitivity of contour shape, angularity and surface texture characteristics of mineral filler particles to particle mineralogy and size.
This study aims to comprehensively investigate the rejuvenation efficiency of various self-developed compound rejuvenators on the physical, mechanical, and aging properties of aged bitumen, asphalt ...mortar, and mixture. The results revealed that the restoration capacity of vacuum distilled-oil rejuvenators on high-and-low temperature performance-grade of aged bitumen is more significant. In contrast, an aromatic-oil based rejuvenator is good at enhancing low-temperature grade and aging resistance. Moreover, the temperature and time of the curing conditions for mixing recycling of asphalt mixture were optimized as 150 °C and 120 min. Furthermore, the sufficient anti-rutting, structural stability, and moisture resistance of recycled asphalt mixture affirmed the rejuvenation efficiency of compound rejuvenators.
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