Abstract
Molecular weight polydispersities of the typical commercial high pressure polyethylenes were estimated by comparing the average molecular weights of different means (Mw, zimm, Mw, dis, M180 or min) obtained from light scattering measurement. Some of these samples were also fractionated by the elution fractionation and GPC methods. It was discussed to be unreasonable to show the molecular weight distribution of the high pressure polyethylenes on the basis of [η] since their molecular structures were different between samples. Comparison of the molecular weight distributions on the basis of Mw which were obtained from light scattering measurement on each fractions revealed that tubular-type polyethylenes generally had more narrow molecular weight distributions as compared with vessel-type polyethylenes, namely, the former had larger amount of low molecular weight portion and had distributions shifted toward lower molecular weight. The amount of microgel was found to be larger in tubular-type polyethylenes.
