A study led by scientists at Rice University in the United States has shown that solid materials made from graphene flakes may be very suitable as bone implant materials.
The personnel involved in this study used a spark plasma sintering technique to make graphene oxide sheets into porous solid materials. Compared with titanium, a traditional bone implant material, this porous material performs better in terms of mechanical properties and biocompatibility.
The researchers believe that this technology, combined with graphite molds, will be used to make very complex graphene materials that take less than a few minutes and are more convenient than special metals.
Chandra Sekhar Tiwary, co-first author of the research paper, Rice University postdoctoral assistant researcher, said: "Graphene is a very interesting material, widely used, and its biocompatibility is also very good. We consider using graphene to As a bone implant material, there are four aspects: mechanical properties, density, porosity, and biocompatibility."
Tiwary said that the industry generally uses spark plasma sintering technology to create complex ceramic parts. “As long as there is a very high voltage, the graphene sheets can be sintered together without high pressure or temperature.†The porosity of the graphene solid material fired by this technique reaches nearly 50%, and the density is only graphite. Half of titanium and a quarter of titanium, but its compressive strength is 40 MPa, enough to be used as bone implant material. The connection between the graphene sheets is sufficient to ensure that the material does not disintegrate in water.
Researchers can also control the density of this material by changing the voltage. They performed a series of tests at room temperature and tried sintering temperatures of 200 to 400 degrees Celsius. The results showed that the sintering temperature was best at 300 degrees Celsius. Tiwary said: "The benefit of two-dimensional materials is that there are many places where they can be connected. For graphene, you can get a very strong connection by breaking through a small activation barrier."
They also tested the load-bearing capacity of this solid material. The materials tested were sintered from two to five layers of graphene and could withstand forces up to 70 micronewtons. Researchers at the Anderson Cancer Center at the University of Texas also succeeded in growing living cells on this material, demonstrating their biocompatibility. In addition, researchers at the Anderson Cancer Center at the University of Texas also found that the sintering process turns graphene oxide sheets into stronger, more stable pure bilayer graphene.
Pulickel Ajayan, a scientist at Rice Materials Labs, who led the research, said: "This material shows the possible use of unconventional materials in conventional technologies, but only if the two-dimensional graphene layer can be made to have a suitable density and Strength of three-dimensional solid material."
"The biggest challenge in achieving this goal is to engineer these nanomaterials to form a connection and a solid contact surface. In this study, using discharge plasma sintering technology to make graphene sheets into three-dimensional solid materials is very effective."
Via Rice.edu
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