Abstract
N, N'-di-n-alkanoyl substituted terephthalic acid dihydrazides with from 2 to 19 alkanoyl carbons were added to polypropylene (PP). Their crystal nucleating activity for PP was evaluated by the rise in crystallization temperature of PP, and their metal deactivation activity was evaluated by the lifetime of PP when in contact with copper. The crystallization temperature and lifetime thus obtained were plotted against the number of carbons of the alkanoyl substituents. It was found that both plots exhibit a group of characteristic and periodic peaks, the positions of which are coincident in both plots. These results suggest that the hydrazides stabilize PP against copper-catalyzed oxidation, not only by deactivating copper, but also by promoting the crystallization of PP.
