Fracture of materials often starts from a crack of the nano or micro scale. The Self healing composite produced mends these cracks before they propagate and lead to fracture. The composite is composed of DIglycidal Ether of BIsphenol A ( DGEBA) cured by Triethylene Tetramine (TETA) and microcapsules of TETA encapsulated in a Poly(methyl methacrylate) shell. A crack in this matrix initiates the healing process by rupturing the capsules. TETA flows from the ruptured capsules into the crack by capillary action and polymerizes, thus healing the matrix.
DGEBA is widely used in the aerospace and marine sectors as a paint, anti corrosion coating, adhesive and resin. Self healing technology increases the lifetime of such a resin significantly. Also, this technology may be implemented in equipment which is hard to access of maintenance or in which defect is hard to detect.
Such an autonomous healing composite system has been produced and the average healing efficiency of 83% is achieved. The production of micro and nano capsules is bases on a widely used and simple technique of solvent evaporation, making manufacture-ability at a large scale easy. Apart from being beneficial for the aerospace and defense sectors, this product can find its way into everyday life, showing high utility in everything from an anti corrosion paint to long lasting adhesive.
It must be noted that this technology is different from other research in this field, as it is based on TETA as the liquid healing agent inside PMMA capsule. This technology is more efficient and cheap. The microcapsules and nanocapsules are biocompatible and have a high shelf life and thermal stability. Up to 87% healing is achieved within hours with just 5% by weight of capsule, which has not been possible before. Overall, this technology will stretch the life of several important products and help save on maintenance.
Submitted by Abhinav Mathur, Guwahati, Assam, India
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