Fold surface of polyethylene single crystals as assessed by selective degradation studies. III. Application of the improved techniques to single crystals

摘要: Previous studies on selective degradation of polyethylene single crystals with fuming nitric acid have been extended, both by using lower concentration which gave better control over the degradation, and resorting to ozone as an oxidizing agent among others enabled temperature be conveniently lowered. The molecular weight distribution was followed gel-permeation chromatography in course degradation. Complete consistency between these different methods has established, modifying some previous conclusions reached this method. principal feature emerges is that we a fold lengths. largest straight stems can stretch across nearly entire layer defined low-angle x-ray period, while there continuous shorter folds terminating deeper down crystals. limiting depth at number becomes negligible identified quantitatively assessed. method analysis described, individual data are discussed detail. This picture surface containing essentially adjacently reentrant uneven length agrees quite recent results other related chain-folded systems (annealed crystals, short chains, bulk structures) obtained laboratories thus appears general validity. consequences model for our polymer particular nature “amorphous” component, discussed.