A study on hydroxyl groups in polyethylene

摘要

AbstractThe possibility of the presence of hydroxyl groups in polyethylene molecular chains has been investigated in observations of infrared spectra of OH and CO stretching vibrations in olefinic molecular chains.n‐Paraffins and fresh medium‐pressure process polyethylenes containing the primary alcohols were used as a model of polyethylene containing hydroxyl groups in the molecular chains. The characteristic wavenumber of the hydroxyl groups slightly contained in the polyethylene in the region 3600–3200 cm−1becomes constant over about 10 of carbon‐atom number of the alcohols, approximately 3336 cm−1. The wavenumber does not agree with ∼3370 cm−1, which has been hitherto assigned to hydroxyl groups in polyethylene molecular chains. Although the absorption due to the hydroxyl groups must appear in the region of CO stretching band in the vicinity of 1050 cm−1if the absorption around 3370 cm−1is due to the hydroxyl groups, the absorption has not been observed. Changes in infrared spectra of polyethylene absorbing water as much as 10 ppm corresponding to the water absorbing capacity are not observed in comparison with those of extremely dried polyethylene. It is concluded that the absorption at 3370 cm−1in polyethylene is not due to the hydroxyl groups and that the groups are not contained at