Analysis of Viscosity Change and Oil Leakage Characteristics According to CaCO3 Particle Size and Anti-Sedimentation Agent Content on Bituminous Emulsion Mastic

This study analyzed the characteristics of viscosity change and oil leakage stability according to the average particle size and content of organic and mineral-based extenders such as CaCO3(CA) and anti-sedimentation (ASE) among materials consisting of bituminous emulsion mastic (BEM). The fabrication of samples for research was done using a melting method of 2L capacity with the production mixing ratio of BEM used in the actual manufacturing process as a standard mixing ratio. Each sample size was adjusted to 16 μm, 5 μm, 2 μm, 1.4 μm and 1 μm, the average particle size of CA as a variable, and the content of ASE for each particle size was set to increase from 1 to 6 times the standard mixing ratio. The analysis found that in all average particle sizes of CA, the viscosity increased as the content of anti-sedimentation increased, and the viscosity was highest at the CA average particle size of 16 μm. The viscosity increased as the average particle size decreased at 5 μm, 2 μm, 1.4 μm and 1 μm. In addition, it was confirmed that the oil leakage stability increased as the average particle size of CA decreased, and the content of ASE increased. The evaluation results showed that specimens that met both workability and oil leakage stability conditions were the specimens with 4 times and 5 times the ASE content at the CA average particle size of 2 μm, and those with twice the ASE content at the CA average particle size of 1.4 μm.

Preparation of Intercalated Organic Montmorillonite DOPO-MMT by Melting Method and Its Effect on Flame Retardancy to Epoxy Resin

An intercalated organic montmorillonite DOPO-MMT was prepared through the melting method using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as a modifier. Epoxy resin (EP) composites were prepared with DOPO-MMT, DOPO, MMT, and the physical mixtures of DOPO+MMT as flame retardants. The microstructure of the flame retardants and EP samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The flame retardant properties, thermal stability, and residual char structure of the EPs were studied by the limited oxygen index (LOI) test, the UL-94 vertical burning test, thermogravimetric analysis (TGA), the differential scanning calorimeter (DSC) test, the cone calorimeter (CONE) test as well as other characterization methods. The results showed that the intercalated organic montmorillonite DOPO-MMT can be successfully prepared by the melting method and that the MMT is evenly dispersed in the EP/DOPO-MMT composite in the form of nanosheets. The EP/DOPO-MMT nanocomposites showed the optimal flame retardancy (LOI, UL-94, PHRR, etc.) among the EPs with DOPO, MMT, and the physical mixture of DOPO+MMT. The flame-retardant grade of the material reached V-0.

THE REFINING OF TITANIUM BY CRUCIBLELESS ZONE MELTING METHOD

The physical substantiation of titanium refining by crucibleless electron beam zone melting (ZM) method in vacuum was presented. Calculations of the equilibrium, limiting and effective distribution coefficients for impurity elements in the base metal were carried out. The refining of titanium was studied experimentally, and samples with a purity of 99.92 wt.% were received. The total content of impurities was reduced by a factor of 1.5 (from 0.12 to 0.08 wt.%). The concentration of interstitial impurities was significantly reduced (oxygen – by 1.3; carbon – by 2; nitrogen – by 2.5 times). The structure and microhardness were investigated.