Year: 1981
Type: article
Abstract: New IR data on the selective oxidation of polyethylene treated with nitric acid are reported. The oxidized groups introduced by the nitric acid are examined with reference to the bands at 1 710 (COOH), 1 650 (ONO2), and 1 550 cm−1 (NO2) as a function of treatment time. The influence of the reaction conditions on the amount and nature of the groups introduced is further investigated. Thus, the ratio of nitro to carboxyl groups after prolonged treatment times is approximately equal to 1/4 if the reaction is performed in open tubes. It is, however, considerably smaller (< 1/8), lowering with time, for t > 40 h, if the treatment is confined into sealed tubes. Furthermore, in addition to the established view of the polymer residues as consisting of paraffinic chains terminated by carboxyl groups the presence of covalent nitrate groups was verified. These groups are probably attached at chain folds, as an intermediary of the reaction during the first treatment hours. Finally, it is further suggested that the nitro groups introduced are preferentially localized at the periphery of the crystallites.
Source: Die Makromolekulare Chemie
Institution: Instituto de Estructura de la Materia
Language: English
Subfield: Polymers and Plastics
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1949600499