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Abstract
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N-acyloxyamine is an excellent radical initiator for the controlled degradation of polypropylene (PP). Irgatec CR 76 (CR-76) is one of the most important Nacyloxyamines for the controlled degradation processes. Here in a DFT mechanistic study on the CR-76- nitiated controlled degradation of PP was performed. The calculated results indicate that the N-O bond cleavage of enol-CR-76 to generate generate nitrogen (N•) and •CH COO radicals be more favorable than that of keto-CR76 to generate nitrogen (N•) and CH 3COO• radicals. In the controlled degradation process of PP, although the generated nitrogen (N•), nitroxyl (NO•), nitrogen peroxide (NOO•) radicals as well as the produced small molecule radicals such as CH3COO•,(CH3)2CH• and (CH3)2CHCH2• radicals could abstract hydrogen from PP, the lattershow better hydrogen abstraction activity than the former. In addition, the NO•, NOO•and ROO• (R=(CH3)2CH) radicals were proposed to be of importance in the radicalcoupling and β-scission of PP• radical after the hydrogen abstraction in thecontrolleddegradation of PP. This might provide some theoretical insights into the designof newN-acyloxyamine radical initiator for the controlled degradation of polymers.
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