Polymer reaction of polycarbonate (PC) as a model of active protective materials has been studied. The specimen molded by injection was decomposed with steam at 120°C and subsequently treated with Na2CO3 at 130°C for 22 days for a preliminary experiment. The molecular weight increased slightly by the treatment. The effects of the deterioration period, temperature, the amount of Na2CO3 and the polymerization methods on the recovery of molecular weight and the kinetics have been conducted. It suggested that (1) phenyl and phenoxy groups at the end of the polymer chains are indispensable to re-combine the ends, (2) the reaction rate of the specimen decomposed for a longer time was higher, (3) Na2CO3 could accelerate the recover reaction, and (4) the deterioration and the recover reactions co-exist. The system of the self-repair and the concept of “passive protection” and “active protection” are discussed. So-called “intelligent materials” are more sophisticated than the self-repairing materials studied here because the intelligent materials have the ability of understanding the reason as the definition of “intelligent”.
