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Chinese and British scientists have successfully developed new low-temperature self-healing composites

researchers mainly from the University of Birmingham in the UK and Harbin Institute of technology in China have found a new method, which can make the cracks of commonly used materials on aircraft and satellites heal naturally when the temperature is lower than the freezing point

this paper, published on open science of the Royal Society of England, shows for the first time that self-healing materials can be controlled and used at very low temperatures (-60 ° C)

the team, led by the University of Birmingham (UK) and Harbin Institute of Technology (China), shows that this material can be used in fiber reinforced materials. It can be used in cases where material maintenance or "replacement is difficult - such as offshore wind turbines, and even microcomputer controlled ones need to display more" impossible " For example, aircraft and satellites in flight

when maintenance is needed, self-healing composites can automatically restore their properties. Under favorable conditions, composites have shown impressive healing efficiency. Indeed, previous research efforts have reached a healing efficiency of more than 100%, indicating that the function or performance of the healing material can be better than that before damage

however, until this paper was published, healing under adverse conditions was considered insufficient, such as at very low temperatures. This new structural composite maintains its core temperature, just as some animals in nature maintain constant body temperature to maintain enzyme activity. A three-dimensional hollow container for the delivery and release of healing agents is embedded in the composite together with a porous conductive element that provides internal heating and thawing

Yongjing Wang, a doctoral student at the University of Birmingham, explained, "these two parts are essential. Without a heating element, the liquid will be frozen at -60 ℃ and the chemical reaction cannot be triggered. Without a hollow container, the healing liquid cannot be automatically transported to the crack." Glass fiber reinforced laminates can achieve more than 100% healing efficiency at -60 ℃. This technology can be applied to most self-healing composites

in the test, copper foam sheet or carbon nanotube LS10 was used to preserve the shape of the mixing chamber of FPL as the conductive layer. The latter can repair itself more effectively, with an average recovery rate of 107.7% and a peak load of 96.22%. Healing fiber reinforced composites, or matrix materials, will therefore have higher interlayer properties - that is, the bonding ability between layers. The higher these characteristics are, the less likely cracks will occur in the future

Mr. Wang added, "fiber reinforced composites are very popular because they are suitable for aircraft or satellites. They are strong and lightweight. But the risk of internal microcracks may lead to catastrophic failure. These cracks are not only difficult to detect, but also difficult to repair. Therefore, the self-healing ability of materials is required."

the group will seek to eliminate the negative effects by using more advanced heating layers for the peak load of heating elements. However, their ultimate (2) high strength goal is to develop more new healing mechanisms for composites, so that they can be effectively repaired under any condition, regardless of the size of the failure

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