Polyurethane-precursor-based Chemically Modified Asphalt and Its Modification Mechanism

The effects of mechanical and chemical modification of TiO 2 nanoparticles on the surface chemistry, structure and fouling performance of PES ultrafiltration membranes

Diamond-like carbon (DLC) flakes were produced using a dual-frequency method: microwave/radiofrequency plasma-assisted chemical vapour deposition (MW/RF PACVD) with the use of methane or its mixture with gases such as hydrogen, argon, oxygen or nitrogen. Their modification was performed using a planetary ball mill with and without a fluid: deionised water or methanol. Changes occurring in the morphology of flake surfaces were presented in pictures taken using a scanning electron microscope (SEM). Their composition and chemical structure were analysed using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The presented research results show that it is possible to control the size of flakes and their chemical structure. An increase in the C-C sp3 bond content in produced carbon-based materials is only possible by modifying DLC flakes during their production process by introducing oxygen or argon into the working chamber together with the carbon-carrying gas. In the processes of mechanical DLC flake modification, it is necessary to add fluid to limit the occurrence of graphitisation processes. The research conducted shows that methanol is best used for this purpose as its use results in a decrease in the percentage of C-C sp3 bonds as compared to the materials, before milling, of only 1.7%. A frequent problem both in the production of DLC flakes and during their mechanical modification is the introduction of additional elements into their structure. Admixing electrode materials from the plasma-chemical device (iron) or grinding beads (zirconium) to DLC flakes was observed in our studies. These processes can be limited by the appropriate selection of production conditions or by mechanical modifications.

Insights into the mechanism of modification by self-assembling starch-based fatty acid esters that cause a pronounced time-dependent effect on asphalt hardness

Facile recycling of Escherichia coli and Saccharomyces cerevisiae cells from suspensions using magnetic modification method and mechanism analysis.

Mechanism of modification by palladium in graphite furnace atomic absorption spectrometry

Properties and modification mechanism of asphalt with graphene as modifier

Compared with ordinary concrete, coal gangue concrete (CGC) is limited by its poor mechanical properties and frost resistance, which seriously restricts its wide application in cold regions. In order to improve the resource utilization rate of coal gangue, this paper takes advantage of the ‘overlapping effect’, ‘micro-aggregate filling effect’ and ‘volcanic ash effect’ of fly ash (FA) and silica fume (SF) and the anti-cracking effect of basalt fiber (BF) to study their effects on the macro performance of CGC and the micro modification mechanism. Modified CGC was prepared by replacing cement with 20% total mineral additives and adding BF. Taking different fly ash and silica fume incorporation ratios (F/S) and the BF content as variables, the research was carried out from two scales of macro performance and microstructure. The results show that the mechanical properties and frost resistance of CGC can be significantly improved by adding mineral additives and BF, and the modification effect is better with a decrease in F/S. When F/S = 1, the compressive strength, splitting tensile strength and flexural strength of the specimens increased by 13.73%, 8.37% and 4.27%, respectively. After 300 freeze–thaw cycles, the specimen was still not damaged by freezing and thawing. At the same time, keeping F/S = 3 unchanged and changing the BF content, it was found that the optimal content of BF was 0.15 vol% under the combined action of BF, FA and SF. In terms of microstructure, the addition of mineral additives and BF segregates and fills the macropores in the structure, greatly reducing the harmful pores and turning them into harmless and less harmful pores. When F/S = 1, the number of multi-harmful pores decreased by 16.89%, and the number of harmless pores and less harmful pores increased by 9.19%, which greatly optimized the pore structure and pore gradation.

Enzymatic hydrolysis lignin (EHL) is a renewable, inexpensive and widely available biomass resource, which has great potentials in improving service performance of bituminous pavement. To develop EHL-modified bitumen and to reveal modification and anti-ageing mechanisms of EHL on bitumen, the impacts of EHL on basic performance, rheological property, micromorphology, chemical compositions, molecular weight distributions and thermal decomposition behaviors of bitumen were studied using basic property tests, dynamic shear rheometer (DSR) test, bending beam rheometer (BBR) test, environmental scanning electron microscope (ESEM) test, Fourier transform infrared spectrometry (FTIR) test, gel permeation chromatography (GPC) test and thermal gravimetric analyzer (TG) test. Results show that bituminous ductility and penetration are decreased, but bituminous viscosity and softening point are increased. Bituminous deformation resistance is improved by EHL. Bituminous cracking resistance is decreased slightly by EHL. Also, the compatibility between EHL and bitumen is satisfactory. Bituminous ageing is delayed owing to abundant phenol hydroxyl groups in EHL, which capture active free radicals produced in bituminous ageing process. Moreover, EHL cross-links with asphaltene to form macromolecular network structures to lower bituminous temperature sensitivity. Finally, EHL dosage of 8% is proposed to prepare EHL-modified bitumen, which effectively reduces energy consumption and increases ecological benefits.

Efficient disposal of composite materials recycled from wind turbine blades (WTB) at end-of-life needs to be solved urgently. To investigate the modification effects and mechanism on SBS-modified asphalt of the recycled glass fiber (GF) from WTB, GF-WTB/SBS composite-modified asphalt was prepared. Dynamic shear rheometer (DSR) and bending beam rheometer (BBR) were adopted to evaluate its performance. FTIR, SEM, EDS, and AFM methods were used to assess coupling agent pretreatment effects on GF-WTB and observe the modification mechanism. The macroscopic tests show that reasonable addition of GF-WTB effectively raises the high-temperature performance and low-temperature crack resistance evaluation index k-value of SBS-modified asphalt, and the optimal content is 2 wt% GF-WTB with 4 wt% SBS. FTIR, SEM, and EDS tests show GF-WTB can be successfully grafted by UP152 coupling agent and show that adhesion of the GF-WTB to the SBS-modified asphalt can be improved. AFM observation shows SBS and GF-WTB have good compatibility, improving the asphalt elasticity and toughness. This study provides a feasible solution for environmentally friendly regeneration of the composite materials from WTB and contributes to the development of the secondary modifier of SBS-modified asphalt.

A negative electrode consisting of Laves-phase alloy particles with a composition of requires more than 20 activation cycles to attain a nominal discharge capacity (ca. ). The activation cycles could be reduced to several times only by mechanical modification with planetary ballmilling and further shortened by mechanochemical modification using a small amount of Al or Mg powder as a modifier. Such mechanical and mechanochemical modifications are also effective for improving high-rate dischargeability. The best result was obtained by grinding the Laves-phase alloy with modifier for at . The reason for quick activation and improved high-rate dischargeability is discussed on the basis of electrochemical impedance, crystallographic structure, particle size, and specific surface area.

PurposeThe purpose of this paper is to enhance the compatibility of titanium dioxide in epoxy resins and thus the corrosion resistance of the coatings.Design/methodology/approachIn this work, TiO2 was modified by the mechanochemistry method where mechanical energy was combined with thermal energy to complete the modification. The stability of modified TiO2 in epoxy was analyzed by sedimentation experiment. The modified TiO2-epoxy coating was prepared, and the corrosion resistance of the coating was analyzed by open circuit potential, electrochemical impedance spectroscopy and neutral salt spray test.FindingsHigh-temperature mechanical modification can improve the compatibility of TiO2 in epoxy resin. At the same time, the modified TiO2-epoxy coating showed better corrosion resistance. Compared to the unmodified TiO2-epoxy coating, the coating improved the dry adhesion force by 61.7% and the adhesion drop by 33.3%. After 2,300 h of immersion in 3.5 Wt.% NaCl solution, the coating resistance of the modified TiO2 coating was enhanced by nearly two orders of magnitude compared to the unmodified coating.Originality/valueThe authors have grafted epoxy molecules onto TiO2 surfaces using a high-temperature mechanical force modification method. The compatibility of TiO2 with epoxy resin is enhanced, resulting in improved adhesion of the coating to the substrate and corrosion resistance of the coating.

The influence mechanism of mechanical modification on fly ash carbonation to solidify heavy metals

Without hindering the taste, making a cigarette less harmful by reducing the percentage of toxic and carcinogenic compounds in the smoke of the cigarette is a challenging task for the current generation of researchers. In the current work, by implementing mechanical, chemical and combined modification techniques, the above stated is tried to mitigate. In addition to the above, the optimum suction pressure, burning time and the number of puffing are also determined. Mechanical modification technique considers filter to cigarette ratio and filter design as the controlling parameters. The mathematical calculation reveals that puffing should stop when the cigarette length reaches 0.15 times of its original length. Furthermore, it is also identified that the concentrations of suspended solids and droplets in the smoke decrease significantly (separation efficiency = 56.81%) if the cigarette to filter ratio is maintained at 2.32. In case of chemical modification, by using various types of adsorbents such as charcoal and Zeolite 13X, the harmful effects are further reduced. These processes depict significant reduction in harmful effect (separation efficiency up to 62.1%) by showing the decrement in the suspended solids and droplets in the smoke due to the adsorption on the active sites of adsorbents. In case of combined modification, the achieved separation efficiency is 66.51%. For the experimentation, an experimental setup fitted with artificial lungs was used.

This article presents a study of the dependence of the biocompatibility of a carbon-based material, namely a 2D C/C composite, on mechanical and chemical surface modifications. The mechanical modifications were surface grinding and polishing, and chemical modifications were made by depositing thin layers of pyrolytic carbon, titanium-carbon and DLC layers. Human osteoblast-like MG 63 cells were cultivated on these materials. The densities of the cells after one-day cultivation and after four-day cultivation, and the average cell spreading area after one-day cultivation, were evaluated in dependence on particular surface roughness parameters. The minima of the cell density on pyrolytic carbon and titanium-carbon layers were found; they were connected with the maxima of the average cell area. For DLC, the cell area decreased as the roughness parameter Ra increased in the range 0.1-10 µm, although the minimum appeared for the density of the cells. Using a multivariate test, the dependences of the biocompatibility parameters on the layer material and on surface grinding were statistically significant. The results suggest that the optimal roughness parameters for MG 63 cell on carbon based surface were Ra ∼ 3.5 µm, RSm ∼0.03-0.08 mm, Rsk ∼0 or negative and Rku ∼ 20, DLC being the best material choice. These values of roughness were obtained by simple mechanical grinding of substrate and coating by DLC layer.

Mechanical modification and ultrasound-assisted osmotic dehydration for mass transfer intensification during blueberry convective drying.