Stone can be drawn into silk to make clothes? This kind of stone can be found on Earth and on the Moon!

The clothes we wear are basically made of cotton, fiber, etc. Have you ever seen clothes made of stone? Hearing this, will some people sneer and say: How is it possible? However, this may come true. Stones can not only be made into clothes, but also made into clothes that can "generate electricity".

Clothes that generate electricity

Basalt is a common paving stone that is abundant on both Earth and the Moon. However, after being processed by special means, it can change its form and become a high-performance fiber material with a metallic luster - basalt fiber.

Basalt fiber finished products

The fiber is 5 to 10 times stronger than steel, but weighs only about 1/3 of the same volume of steel. It also has the characteristics of heat insulation, insulation, and radiation protection. What is more valuable is that there is basically no harmful substance discharged during the manufacturing process of basalt fiber, and the pollution to the environment is very small. Therefore, some people figuratively call its manufacturing technology "the art of turning stone into gold."

my country has listed basalt fiber as one of the four major fiber materials for development and has achieved industrialized production. Its application range is also very wide, and it can be used in aviation, aerospace, construction materials, road and bridge construction, shipbuilding, wind power generation and other fields.

At present, the application of basalt fiber is mainly in the reinforcement of composite materials, but some people have begun to use basalt fiber as clothing fabrics. Some researchers use simulated lunar soil as raw materials to produce customizable basalt fibers, and then prepare a triboelectric basalt textile that can not only be made into clothes, but also turn clothes into a wearable device.

High temperature flame calcination experiment of triboelectric basalt textiles

After being patted, this textile can "generate electricity" and can charge watches or mobile phones like a power bank. This is because scientists use the friction effect to add a polyimide fiber to the basalt fiber. When two different fibers come into friction contact, the energy generated by human movement can be converted into electrical energy.

In addition to generating electricity, scientists have also developed a wearable extreme temperature alarm system, which allows triboelectric basalt textiles to not only remain "unharmed" in a fire, but the wearer can even send a distress signal to rescuers by slapping it.

A series of experiments have shown that this new type of textile can generate electricity in extremely high temperature (520°C) or extremely low temperature (-196°C) environments. In the future, it is expected to be used in extreme environments such as high and low latitudes, high altitudes, deserts, and even space.

The disobedient stone

When ordinary people are on a low-battery call, their clothes can charge their phones; when firefighters charge into a sea of ​​fire, their clothes can insulate and withstand high temperatures; when astronauts travel in space, their clothes can block radiation. But turning hard stone into clothes, and functional clothes at that, is not an easy task.

Basalt is a kind of stone that is not so "obedient". It is a natural product with a large fluctuation in chemical composition. Therefore, the performance of basalt fiber itself is unstable during preparation. Secondly, the process of turning basalt ore into basalt fiber requires two processes: melting and drawing. During the basalt melting process, various minerals in the ore gradually melt. Once there is an incompletely melted crystal phase, it is easy to form a secondary crystal nucleus; during the basalt drawing process, the basalt melt also has a tendency to crystallize to varying degrees. This crystallization needs to be avoided as much as possible, otherwise it will affect the characteristics of the fiber and the quality of the final product.

Both the melting and drawing processes have very strict temperature requirements. First, large pieces of basalt are placed at a high temperature of 1500℃ for 2 to 4 hours to be melted and broken into uniform small particles. The small particles are then placed in a spinning device and drawn into basalt monofilaments at 1350℃. In the melting stage, if the temperature is too low, the basalt may not be completely melted, and small particles may be mixed in it, which may easily cause bubbles and stones to form new particles; in the drawing stage, if the melting temperature is too high, the viscosity of the basalt melt decreases, reducing the drawing efficiency and fiber strength.

Basalt

In addition to temperature, the drawing speed also affects the quality of basalt fiber. The newly-made fiber is like a baby, which is very fragile at birth and needs to be carefully cared for. If too much force is used, the fiber will be broken in one go; when the baby grows up, it is necessary to speed up the drawing speed to give it a stretching force to promote its growth.

In order to improve the quality of basalt fiber, scientists have conducted a lot of research on melting, drawing temperature and technology. Although my country started late in the research on basalt fiber, after continuous and difficult exploration, scientific researchers have overcome many difficulties in manufacturing technology, making China one of the few countries in the world that has mastered basalt fiber production technology.

It is not easy to turn stone into fiber, and making basalt textiles truly wearable is also a global problem. Stone fiber feels harder and a little itchy, which is fine for fireproofing and heat insulation of industrial equipment, but as clothing, it must be treated for comfort and skin-friendliness.

Basalt fiber twill fabric

How to make basalt textiles soft? Scientists have proposed the idea of ​​wrapping each bundle of basalt fibers with comfort fibers to make composite yarns, which have been successfully applied to firefighting uniform fabrics. The mainstream firefighting uniform fabric, aramid, has a heat resistance limit of 300°C, while the heat resistance limit of basalt textiles can reach 1000°C, can be used for a long time at 600°C, can withstand more than 10,000 twists and turns, and the unit price is only 1/3 of that of aramid.

In addition to making composite yarns, some scientists also envision coating the basalt fiber with a layer of wetting agent using an oiler after the fiber is formed, thereby enhancing the softness of the fiber.

With the continuous development of science and technology, today's textiles are no longer limited to meeting traditional needs, and the same is true for basalt textiles. Triboelectric basalt textiles are a preliminary attempt to turn textiles into wearable devices. Although its power generation efficiency is still relatively low and can only be used for emergency charging of watches or mobile phones; although the signal transmission of wearable extreme temperature alarm systems is also wired, in order to improve the signal stability and human comfort of textile devices, wireless improvements are still needed; but the step forward taken by triboelectric basalt textiles undoubtedly makes everyone more looking forward to the exploration of making new textile clothing realize more functions.