Incorporation Of Wollastonite Research Articles

Property Improvement of Recycled Nylon 6 by Thermoplastic Poly(Ether-Ester) Elastomer and Wollastonite

Recycled nylon 6/thermoplastic poly (ether-ester) elastomer (Hytrel) (R-N6/H) composites filled with various contents of wollastonite (WT) (10, 20 and 30 phr) were prepared using the twin-screw extrusion and injection molding process. In this study, the blend and composite materials were characterized in terms of mechanical and morphological properties. The results showed that the impact strength of the R-N6/H blend was improved with the addition of Hytrel, whereas the tensile strength, tensile modulus, flexural strength and flexural modulus of the R-N6/H blend were decreased. Then, the R-N6/H blend was filled with WT to prepare composites. Interestingly, the incorporation of WT in the R-N6/H blend overcame the inferior properties of recycle blend materials by the mechanical properties enhancing. Despite the good mechanical properties of WT composite materials, they were still affected the elastic properties due to the stiffness characteristic of WT.

Influence of nano material (TiO2) on self compacting Geo polymer concrete containing Flyash, GGBS and wollastonite

In the modern age, concrete has become major component in construction field which results in global warming as it contains high amounts of cement. To reduce the carbon footprint and help environment, In our research, cement is elemenated and this type of concrete is called “Geo-polymer concrete”. Binders like Fly-ash, Wollastonite and Ground Granulated Blast Furnace Slag (GGBS) are used and Alkali activators like sodium hydroxide and sodium silicate are used to improve the binding properties of the concrete. Titanium oxide is used to develop self-compacting Geo-polymer concrete (SCGPC). At ambient curing conditions, Fresh and hardened properties are tested at 7, 14 and 28 days. SCGPC mixes are developed by adding Titanium oxide to mixes with and without wollastonite at 2%, 4%, 6%. To obtain the optimum results we need to perform some Fresh and as well as the Hardened properties. The fresh properties tests include slump flow. Hardened properties of the concrete include the Compressive strength and Split Tensile. The optimum test results were obtained at 4% TiO2 with and without wollastonite. There is 18–20% increase in the strength by incorporation of wollastonite.

The resistance to high temperature of magnesia phosphate cement paste containing wollastonite

This paper aims to study the effect of wollastonite addition on the behavior of magnesium ammonium phosphate cement (MAPC) and magnesium potassium phosphate cement (MKPC) pastes exposed to different high temperatures. Different dosages of wollastonite were added to replace MgO powder in these two types of magnesia phosphate cements. The paste specimens were exposed to 105 °C for 24 h and to different temperatures of 200, 400, 600, 800 and 1000 °C for 3 h and then cooled to room temperature for different tests including mass loss, visual appearance, compressive strength, mineral composition and microstructure observation. The results show that the specimens containing 10 % wollastonite for both MAPC and MKPC mixtures presents the most improved high temperature resistance due to the excellent heat stability of wollastonite mineral and the refined microstructure. And the addition wollastonite has little influence on the hydration products of these two magnesia phosphate cements. Therefore, the incorporation of wollastonite is a potential method to improve the heat-resistance of MAPC or MKPC.

Fabrication and characterization of bioactive silk fibroin/wollastonite composite scaffolds

Composite scaffolds of silk fibroin (SF) with bioactive wollastonite were prepared by freeze-drying. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy analysis showed that random coil and β-sheet structure co-existed in the SF scaffold. The mechanical performance, surface hydrophilicity and water-uptake capacity of the composite scaffolds were improved compared with those of pure SF scaffold. The bioactivity of the composite scaffold was evaluated by soaking in a simulated body fluid (SBF), and formation of a hydroxycarbonate apatite (HCA) layer was determined by FT-IR and XRD. The results showed that the SF/wollastonite composite scaffold was bioactive as it induced the formation of HCA on the surface of the composite scaffold after soaking in SBF for 5 days. In vitro cell attachment and proliferation tests showed that the composite scaffold was a good matrix for the growth of L929 mouse fibroblast cells. Consequently, the incorporation of wollastonite into the SF scaffold can enhance both the mechanical strength and bioactivity of the scaffold, which suggests that the SF/wollastonite composite scaffold may be a potential biomaterial for tissue engineering.

Preparation and characterization of bioactive collagen/wollastonite composite scaffolds

A novel biodegradable collagen/wollastonite composite was prepared as three-dimensional scaffolds by freeze-drying method. Scanning electron microscope (SEM) micrographs of scaffolds showed a continuous structure of interconnected pores, and pore size was about 100 microm. The tensile strength of the scaffolds was improved by incorporation of wollastonite and the in vitro bioactivity of the scaffolds was evaluated by examining the hydroxyapatite (HA) deposition on their surface in simulated body fluid (SBF). After soaking in SBF for 7 days, collagen reconstituted to fibers and HA nodules formed on collagen fibers. The result suggests that the incorporation of wollastonite could improve the mechanical strength and the in vitro bioactivity of the composite. The scaffolds could be a potential biomaterial for bone tissue engineering.

Preparation and characterization of bioactive and biodegradable Wollastonite/poly(D,L-lactic acid) composite scaffolds

Composite scaffolds of poly(D,L-lactic acid) (PDLLA) with bioactive wollastonite were fabricated by the conventional solvent casting-particulate leaching method. The pore structures and morphology of the scaffolds were determined by scanning electron microscopy (SEM). The bioactivity of the composites was evaluated by soaking in a simulated body fluid (SBF), and the formation of the hydroxyapatite (HAp) layer was determined by SEM and energy-dispersive spectrometer. The results showed that the wollastonite/PDLLA composites were bioactive as it induced the formation of HAp on the surface of the composite scaffolds after soaking in SBF for seven days. In addition, pH and ion concentration changes of SBF solutions with composite scaffolds were examined. The results showed that the composites could release Ca and Si ions, which could neutralize the acidic degradation by-products of the PDLLA, and stabilize the pH of the SBF solutions between 6.7 and 7.2 within a three-week soaking period. Furthermore, the measurements of the water contact angles suggested that incorporation of wollastonite into PDLLA could improve the hydrophilicity of the composites and the enhancement was dependent on the wollastonite content. All these results suggest that incorporation of wollastonite into PDLLA might be a useful approach for the preparation of composite scaffolds for tissue repair and tissue-engineering applications.

Fabrication and characterization of bioactive wollastonite/PHBV composite scaffolds

Composite scaffolds of polyhydroxybutyrate-polyhydroxyvalerate (PHBV) with bioactive wollastonite were fabricated by a compression moulding, thermal processing, and salt particulate leaching method. Structure and mechanical properties of the scaffolds were determined. The bioactivity of the composites was evaluated by soaking in a simulated body fluid (SBF), and the formation of the hydroxyapatite (HAp) layer was determined by Scanning Electron Microscope (SEM) and Energy-Dispersive Spectrometer (EDS). The results showed that the wollastonite/PHBV composites were bioactive as it induced the formation of HAp on the surface of the composite scaffolds after soaking in SBF for 14 days. In addition, the measurements of the water contact angles suggested that incorporation of wollastonite into PHBV could improve the hydrophilicity of the composites and the enhancement was dependent on the wollastonite content. Furthermore, the pH and ion concentration changes of SBF solutions with composite scaffolds showed that the composites released Ca and Si ions, which could neutralize the acidic by-products of the PHBV and stabilize the pH of the SBF solutions between 7.2 and 7.8 within a 3-week soaking period. All of these results suggest that the incorporation of wollastonite was a useful approach to obtain composite scaffolds with improved properties.

Tensile strength and rupture energy of hybrid poly(methylvinylsiloxane) composites reinforced with short PET fibers and wollastonite whiskers

In this paper, the tensile strength and rupture energy of hybrid poly(methylvinylsiloxane) composites reinforced with short PET fibers and wollastonite whiskers have been studied. It was observed that for a fixed fiber volume fraction, the tensile strength and rupture energy of the hybrid composites first decreased and then increased with wollastonite whisker volume fraction. Analyses of the fiber efficiency factor for the strength and rupture energy of the composites indicated that the fiber pull-out force and pull-out energy were changed as a result of the incorporation of wollastonite. The hybrid reinforcing mechanism is also discussed in this paper.

Enhanced viral interferon induction by the mineral wollastonite.

The in vitro activity of the fibrous mineral wollastonite (CaSiO3) on the interferon system was investigated. Wollastonite enhanced the induction of interferon by influenza virus in mammalian (LLC-MK2) cell monolayers but the mineral per se did not induce interferon. The magnitude of enhanced interferon induction was dependent on mineral concentration, particle size, and its time and sequence of addition onto cell monolayers. A "synergistic effect" on viral induction of interferon was noted when cell cultures were interferon-primed and then treated with wollastonite. Interferon yields were significantly higher than those obtained by the use of either the primer or wollastonite alone. That influenza virus multiplied in wollastonite-treated cells to a level that was sevenfold less than that in normal cells was associated with increased interferon production. The ability of interferon to confer antiviral cellular resistance was not impaired by wollastonite. The findings of this study suggest that the incorporation of wollastonite in appropriate interferon inducer-host cell systems may be useful for augmenting interferon production.