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The technology of Self

2010.10.18   13:32

The technology of Self-healing coating

--- Catalyst & polymerization mechanisms

For self-healing processes to be efficient, the healing system should have a fast rate of curing. Furthermore, the catalyst should be inert during service and capable of dissolving in the monomer and activating the reaction at the onset of the damage. In their report , white and co-workers employed dicyclopentadiene (DCPD) as the monomer. The monomer forms a tough crosslinked network by ring-opening metathesis polymerization (ROMP).ROMP of DCPD was initiated by using a Grubbs’ catalyst that has high metathesis activity with the monomer. By adjusting the isomer ratio of DCPD, reaction rate and the time needed for dissolution of the catalyst was controlled to achieve high toughness recovery in an epoxy matrix. While Grubbs’ catalyst possesses many of the attributes required for a self-healing catalyst phase, high cost, heat stability has led to utilization of alternative ROMP catalysts. Among them, tungsten chloride and co-activator has shown similar properties as the Grubbs’ catalyst at lower cost with a high melting point of 275 compared to 153 for the Grubbs’ catalyst.


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