화학공학소재연구정보센터
Materials Science Forum, Vol.363-3, 309-312, 2001
Molecular weight effect on the microstructure and local motion in high molecular weight polymer observed by positrons
The positron annihilation lifetime spectroscopy (PALS) was applied on the high molecular weight (HMW) polymer samples as polystyrene (PS) and poly(methyl methacrylate) (PMMA) with different molecular weight. It's very interesting to find that the free volume number increases and the distribution is broadened with the increase of the molecular weight. The reasons were discussed from the coupling model. The entanglements in high molecular weight act as physical cross-linkages, which limit the segmental mobility. The PALS results might implied the fast motion of side group is dependent to the molecular weight in HMW linear polymer.