Combined with aerogel fibers, Chinese scientists develop anti-burn electronic fabrics


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Combined with aerogel fibers, Chinese scientists develop anti-burn electronic fabrics

  • Categories:NEWS
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  • Time of issue:2022-03-09 10:36

Combined with aerogel fibers, Chinese scientists develop anti-burn electronic fabrics

If the fire suit is exposed to high temperature, real-time temperature monitoring can be performed, and an alarm signal can be sent to the wearer in time before the fire suit is damaged by high-temperature flames to remind firefighters to evacuate safely. Then there won't be as many firefighters to die.

The researchers combined the lightweight and woven properties of silica aerogel fibers with the resistance of semiconducting nanomaterials to change with temperature to simultaneously impart these three important properties to a flexible electronic fabric.

Ultimately, they developed this sensing fabric that combines ultra-sensitive temperature response and self-powering capabilities, and used it for high temperature warnings in firefighters' protective clothing.

The experimental results show that when the surface of the prepared protective clothing is exposed to a high temperature flame above 350 ℃, an instant alarm can be realized, thereby reminding firefighters to evacuate to a safe distance around the fire source in time, so as to avoid the protective clothing from being exposed to high temperature and losing its protective performance.

In the preparation process, Wang Jinfeng's team used intelligent flexible fire early warning sensing material, which has excellent flame retardancy, heat insulation, light weight and flexibility, and overcomes the long response time, poor early warning, and high flexibility of traditional smoke detectors. Disadvantages such as inability to integrate into fire clothing.

The specific pain point to be addressed by the study is that fire is one of the most frequent disasters that threaten public safety and social development. In the process of fire fighting, fire clothing is a basic equipment that can protect them from burns.

Due to the existence of the heat insulation layer of the fire suit, firefighters cannot know the temperature of the outer layer of the fire suit in real time and accurately during fire rescue operations, and the temperature inside the suit can only be subjectively felt.

In a highly complex and dangerous fire environment, the high temperature environment can easily lead to damage to firefighters' suits, which will bring great hidden dangers to the lives of firefighters.

As far as the research process is concerned, Wang Jinfeng first prepared aerogel fibers of different diameters through the wet spinning process, and further woven them into fabrics. The process is shown in the figure below.

After the fabric was prepared, the effect of the surface functional coating on the air permeability and electrical conductivity of the fabric itself was investigated. In the process of wearing, the fabric will inevitably bend and deform. However, the team found through tests that the electronic fabric can maintain stable electrical resistance under different bending angles.

At the same time, Wang Jinfeng's team also found that even under the 180° bending condition, the electronic fabric can maintain a stable resistance change and a stable fire alarm trigger time even after being repeatedly bent for hundreds of times. This shows that the electronic fabric can output signals relatively stably in actual use, and will not be affected by the deformation of the fabric.

Fire protective clothing can be divided into four layers: the first to fourth layers are flame retardant layer, moisture-proof layer, heat insulation layer and comfort layer. In the study, Wang Jinfeng integrated a piece of electronic fabric as an additional layer in the protective clothing between the first and second layers to monitor the surface temperature of the clothing. In extreme fire environments, electronic fabrics can signal an alarm when protective clothing fails.

To further demonstrate the repeatability of the electronic fabric's fire alarm performance, the team repeatedly exposed the electronic fabric to and away from the flame in cycles of 20 and 40 seconds, while recording current changes.

The results show that when the fabric is exposed to flame, its output current is very stable with a standard deviation of 5%, which indicates that the electronic fabric has good stability and repeatable fire alarm capability.

In addition, Wang Jinfeng's team also observed that the resistance ratio of the electronic fabric before and after heating will decrease with the increase of the external temperature, and the response time of the electronic fabric will also shorten significantly with the increase of temperature.

At present, traditional fire warning sensors are mainly based on smoke alarms and infrared alarms. However, due to its large size, it is not suitable for bonding to the fabric of fire protection clothing. Once ignited, forest fires typically burn quickly, spreading flames quickly over large areas, which can cause firefighters to get lost and unable to determine the correct evacuation route, increasing unnecessary casualties.

Therefore, it is very important to incorporate an automatic fire rescue positioning system into the fire suit to send distress signals. The wearable intelligent fire early warning device developed this time can make firefighter clothing have a high temperature warning function, thereby ensuring safety protection during firefighting operations.

It is reported that the fire early warning sensor has the performance of flexible, high sensitivity and repeatable monitoring of fire temperature, overcomes the shortcomings of traditional fire detectors such as long response time and cannot be combined with fire protection fabrics, thereby opening the application of flexible electronic fabric fire early warning devices. door.

The fire early warning electronic textile prepared this time has both sensitive fire early warning performance and self-power supply capability. It is both a textile and a flexible sensor device, which can be woven inside the fire suit to achieve repeatable temperature monitoring, and has the characteristics of heat insulation, fast speed, real-time, and flame retardant.

In the next step, the team will prepare aramid-based aerogel fibers, which are the main raw material for fire-fighting clothing fabrics and have the characteristics of high strength and high flame retardancy. As a high temperature warning sensing material, it can be integrated into protective clothing to better adapt to the high temperature environment of fire.