Papers by Keyword: Mechanochemistry

Abstract: Using adjustable speed crushing regeneration test device for the recovery experiment of thermosetting phenolic plastic waste, this paper analyses the principle of recovery process. Through particle size analytical technique, FTIR, XRD and SEM etc. various testing method is analyzed mechanochemical effects of crushing process. Research the speed, time, temperature process parameters of the influence of recycling process conditions. According to the experimental results, it established the mechanochemical model and analyzed the degradation and regeneration mechanism of thermosetting phenolic plastic waste.

Abstract: Pentachlorophenol (PCP), metallic oxide and ball-grinder medium steel beads are ground together in a ball-grinder under room temperature and pressure to degrade PCP. A AgNO₃ standard solution was used to titrate the Cl^--containing solution made from grinding product. The dechlorination rate used to show the degradation result of PCP was calculated through the amount of AgNO₃ standard solution. The results show that dechlorination rate is increased with grinding time increasing, and the product shows a black hue after 2.5h grinding, which might be a sigh of elemental formation carbon; The bigger the CaO/PCP molar ratio is, the better the dechlorination rate is. With the molar ratio of 50:1,the dechlorination rate is over 90%, while 60:1 for almost 98%;

Abstract: Highly disperse powders of complex morphology, micro- and nanostructure were obtained by treatment of quartz in a planetary-centrifugal mill of a dynamic action in the presence of different organic substances. The surface layer with the thickness of 10-70nm modifying the particle of quartz after mechanochemical treatment is a polymer with encapsulated nanosized particles of iron. Powder material from such highly disperse composition particles of modified quartz is characterized by ferromagnetic and electroconducting properties. A galvanic effect in a nanosize scale is possible to take place on the surface of particles consisting of a polymer nanostucturized film with sites supersaturated with metallic and carbon clusters. The practical realization of such structures is promising when producing highly active sorbents as well as for collecting of oil products spills on the surface of water.

Abstract: Oligo(phenylimines) hereafter named PI6, PI8 and PI9 were synthesized by condensation reaction between the terephtalaldehyde and diamines of different length size (diaminohexane, diaminooctane and diaminononane) via mechanochemistry. The reactions were carried out without solvent or catalyst and completed after only 90 minutes. The products were characterized by ¹H-NMR, UV-Vis, FT-IR spectroscopy, GPC, DSC and Small angle X-ray diffraction. Thin films were prepared by spin coating from concentrated solutions on glass and quartz substrates and mechanically rubbed with a polyacrylonitrile tissue. The oriented films were studied by both Laser Scanning Confocal Microscopy (LSCM) and UV-Vis spectroscopy. With this last technique, the higher optical dichroism was observed for PI6. The oriented films of this oligo(phenylimine) were thus used as patterns to induce molecular orientation of a fluorescent phenyleneethynylene polymer in order to obtain polarized light emission.

Abstract: Some dry and wet grinding experiments have been respectively conducted on titanium dioxide which is a noble photocatalyst material in a mortar, a tumbling mill and a planetary mill. Anatase is apt to transform to rutile via a metastable phase brookite in every kind of mills in the case of dry grinding. And it hardly takes place for phase transformation from rutile to other forms. It is shown that the kind of mill has not decisive effect on the mechanochemical polymorphic transformation of titanium dioxide, which merely influences the rate of phase transformation. On the other hand, the addition of other liquid media, such as water and acetone, is helpless for phase transformation of anatase. Only anatase can transform to metastable phase brookite by wet grinding. When ground titanium dioxide is heated, the amorphous phase is easier to transform to rutile than metastable phase brookite at lower temperature.

Abstract: This paper compares two methods for synthesizing a carbonate compound, Mg-Al-CO3 (Mg:Al=2:1), which is a layered double hydroxides (LDHs). The methods are mechanochemical method and hydrothermal method. The products characterized by XRD、SEM、FT-IR and TG-DTA. The results indicated that the target material was synthesized by different methods. The two kinds of well-crystallized materials with the same basal spacing d003=0.77nm, but their morphology were not same. The crystallite size of hydrothermal was larger than mechanochemistry.

Abstract: The pressure-viscosity relationships of phosphate synthetic oil and other two kinds of similar atmospheric viscosity synthetic oils were studied using ultra-high pressure capillary viscometer. The pressure-viscosity relationship of phosphate synthetic oil is much better than the other two kinds of synthetic oils. The impact of pressure on viscosity is not limited to purely physical factors. The pressure can cause a variety of chemical reactions in some cases. The investigation results of mechanochemistry of phosphate synthetic oil at high pressure reveal that the physical state of phosphate synthetic oil changed from liquid into glassy amorphous state under high pressure, and the color varied from transparent into milky white. The mechanochemistry of phosphate synthetic oil was analyzed using the infrared spectroscopy and gel permeation chromatography, and the results indicate that under high pressure, the oxidation reaction of phosphate synthetic oil occurred, and the molecular weight distribution changed with the increase of the low molecular weight region. The reason of the mechanochemistry phenomena was that phosphate synthetic oil molecular chain disconnects to inform great radical. The great radical has strong activity, and reacts with other free radicals acceptor (oxygen, etc).

Abstract: In this work, novel types of colored, organic and water based paints have been developed. These paints can be produced less expensively and have equivalent or better properties compared to existing paints in the market. These new paints use organic nanocrystalline dyes (about 10 nm in size), which produce the various colors by absorption. The results are achieved with pigment composites containing nano-Cu-phthalocyanine (CuPC) pigment crystallites and finely precipitated and ground micro Al(OH)3 distance-holder (“spacer”) disks.

Abstract: During the fine comminution of clay minerals and layered silicate materials with relative large volume of specific surface area appreciable changes in chemical and minerological compositions can be observed. In this paper is described the mechanochemical investigation of conventional clay minerals from „Lenti” region (Hungary), having natural BET specific surface larger than 35-40 square metres per grams. The laboratory experiments made by author had shown an intensive reduction of specific surface volume at the beginning of grinding, further relatively slow growth and reduction of BET and Langmuir surfaces were observed. The content of mineral Muscovite–2M1 – (K, NH4Na)Al2(SiAl)4O10(OH)2 – has decreased and the contents of Quartz – SiO2 – and Illite-1M (NR) – KO.7Al2(SiAl)4O10(OH)2 – have increased considerable depending on grinding time. Increasing the milling time the amount of Albite – NaAlO.91Si3O8 – and other mineral components were also not stable, but their content have varied not so strong as Muscovite–2M1 or Quartz and Illite–1M. The examined clay minerals had a certain proportion of amorphous particles as well, but in this contribution only the changes in proportions of crystalline particles are described.

Abstract: Commercial sedimentation CaCO3 was ground by a vibration rod mill to investigate the physicochemical properties of mechanically activated CaCO3.When the CaCO3of the calcite structure was ground, the intensities of the crystal facesof calcite was decreased by distortions and so on, and the aragonite appeared as the grinding proceeded. The formed aragonite was transformed to the calcite when the sample was heated at 773K for3.6 ks. The dissociation pressure of CO2 of the ground CaCO3was larger than that of the non-ground CaCO3.The enthalpy; entropy and specific heat of change of the dissociation reaction were obtained. At high temperature, the emission rate of the ground CaCO3 was slightly larger than that of the non-ground CaCO3. At room temerature, the CaCO3 adsorbs CO2, and it desorbs the adsorbed CO2. The amount of adsorbed CO2 on the ground CaCO3 was larger than that of the non-ground CaCO3.