Papers by Keyword: Wollastonite

Abstract: In order to utilization the molybdenum tailings which be deposited in large quantities. Test used it to prepare glass-ceramics as main raw material, TiO₂ as nucleation agents and CaO-Al₂O₃-SiO₂ system and wollastonite as the principal crystalline phase. Heat treatment system of glass-ceramics was based on the differential thermal analysis. The crystalline phase, microstructure and characteristics of glass-ceramics were analysis by XRD, SEM and physical, chemical properties test. The result shows that the performance of glass-ceramics was superior to the other types of building decoration stone.

Abstract: In the paper, ultrafine quartz, sericite and wollastonite modified with silane coupling agents KH-570 were incorporated into natural rubber(NR). The synergisitc effect on reinforcing NR caused by the three types of fillers was investigated under a same vulcanizing formulation and process. The mechanical properties and microstructure of the vulcanizates were conducted through mechanical testing and scanning electron microscopy(SEM). The results of mechanical properties tests showed that when one of these three fillers was loaded within NR alone, the tear strength and permanent set of NR vulcanizates filled with quartz could reach 27.61 kN m^-1 and 16.0%, respectively, stress at 300% elongation of NR vulcanizates filled with sericite could attain 4.69 MPa, and the tensile strength and elongation at break of NR vulcanizates filled with wollastonite could get to16.64 MPa and 951.21%, respectively. Under the condition that the filler loadings were 40 parts per hundred parts of rubber(phr), and the mass ratio of quartz, sericite, wollastonite was 1:1:3, the tensile strength and tear strength could come up to 17.33MPa and 27.54 kN m^-1. The mechanical properties of NR composites filled with mixtures were found to be complemented by those three types of minerals. SEM results revealed that the fillers are well dispersed in the rubber matrix in the parallel arrangement with a densest stack, and the synergistic reinforcment effect of the fillers on NR was obvious.

Abstract: The reclaimed rubber was used for many fields, but the mechanical properties especially elongation at break of reclaimed rubber couldn’t meet the requirement due to its recycle property. It was proved that the wollastonite with fibrous structure could improve the mechanical properties in many composite. In this study, the reclaimed rubber modified by wollastonite was prepared by the mechanical agitation and open roll mixing methods. The composite was characterized and tested after the renewed vulcanization, and the mechanical properties could be improved. It was observed from experimental data that the elongation at break could enhance from 238% to 300%. Moreover, the tensile strength could increase to some extent.

Abstract: The wollastonite with fibrous structure can be used as the filler in the composite. In this paper, the composite was prepared by incorporating the wollastonite into butadiene styrene rubber (SBR) matrix through the mechanical agitation and roll mixing technologies. Mechanical properties of SBR filled with different amount of wollastonite content were studied and compared. It was shown that the mechanical properties of SBR filled with wollastonite could be improved significantly. The tensile strength and elongation at break were increased with the increase of the wollastonite. The tensile strength could be enhanced from 4.1MPa to 5.0MPa, and the elongation at break from 389% to 572%.

Abstract: Wollastonite was inorganic modificated by coating aluminium silicate with heterogeneous deposition method.SEM, XRD, FTIR, BET surface area analyzer were used to characterize the product. XRD result shows that wollastonite is coated with nano-aluminium silicate. BET result shows that the specific surface area of particles increases by 200%. FTIR result shows that the content of OH group increases.Whiteness test shows that the whiteness increases by 2.0. Application test shows that the polypropelyne(PP) products filled with inorganic modificated powder have superior physical properties or mechanical properties(tensile strength 20.45Mpa, bending strength 38.02Mpa) than that with uncoated wollastonite and pure PP and the heat distortion tempeature increases by 28.6°C than pure PP.Inorganic modification of wollastonite can improve the joint interface between wollastonite and PP.

Abstract: Introduction of White carbon black’s property and the technological flow of developing. White carbon black by using Wollastonite and factors that influences it .The conditions of the experimental are that the ratio of hydrochloric acid’s volume(hydrochloric acid’s concentration is 36%) and the weight of Wollastonite is 1.50 L/kg ,reactive concentration is 20%,the temperature is 50 centigrade, and reaction time is 30 minutes. Then purify it in order to meet the requirement of rubber reinforcement and the content of SiO2 is over 90%.The White carbon black coproduct is CaCl2, the purity of which is 96.76%,and can be used in industry.

Abstract: The wollastonite/PP composites were manufactured by twin-screw extruder and the effects of compatabilizer, feeding method and screw configuration on the properties of wollastonite/PP composites were investigated in this paper. The dispersion of fibrous wollastonite in PP matrix was determined by scanning electron microscope (SEM). The results showed that the strength, toughness and flowability of the composite were simultaneously guaranteed by using three different types of PP resins, and the interfacial adhesion was improved greatly by adding the compatabilizer of PP-g-MAH, which increases the comprehensive properties of wollastonite/PP composite. The fibrous dispersion of wollastonite in PP matrix was achieved by using of side feeding and the weak-shear screw configuration, which reaches the good reinforcing effect.

Abstract: Luminescent wollastonite-CePO4 nanocomposites have been successfully synthesized using Ca(NO3)2•4H2O, Na2SiO3•9H2O, and CePO4 by hydrothermal method at 200 oC for 24 h. The precursor nanorods with diameters about 20 nm and lengths several micrometers were obtained by hydrothermal treatment, and after calcination at 600 oC for 3h, the precursor nanorods transformed to wollastonite-CePO4 nanocomposites. Considering the experiment result, a possible growth of the precursor nanorods via the rolling mechanism was also proposed. This is the first report about the synthesis of luminescent wollastonite-CePO4 nanocomposites. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDS), and photoluminescence (PL).

Abstract: Hybrid silica-organic polymer aerogels based on tetraethoxysilane (TEOS) have been synthesized, polydimethylsiloxane (PDMS) and methyltriethoxysilane (MTES) have been used as organic phases. Synthetic wollastonite powder was added as bioactive phase. The composites were prepared by dispersing wollastonite powder in the sol with the assistance of high power ultrasounds to control the gelling time. Wet composites were dried under supercritical conditions of the solvent. The mechanical characterization was performed by uniaxial compression and by nanoindentation. Young`s modulus from uniaxial compression increase from 5 MPa to 100 MPa for increasing MTES content and also rupture modulus was enhanced from 0.85 MPa to about 50 MPa, so the incorporation of cross linkers in this kind of aerogels, was proven to enhance the mechanical resistance. However the inclusion of wollastonite powders provokes a dropping of the Young’s modulus and hardness. All the composites showed bioactivity by the formation of an apatite layer when immersed in Simulated Body Fluid (SBF).

Abstract: Gentamicin sulphate was mixed with two different sol-gel derived calcium silicates (akermanite or wollastonite). Each of the mixtures was isostatically pressed. Samples were immersed in simulated body fluid for 21 days. The presence of the antibiotic showed no effect on the in vitro bioactivity of the ceramics. For evaluating the gentamicin sulphate release, samples were immersed in a phosphate buffered saline solution for different periods of time. Most of the gentamicin sulphate was released during the first 7 days. However, akermanite showed a lower antibiotic release rate than that observed for wollastonite.