wizyta

od 2020-09-20

Title: Molecular dynamics in cyclic olefin copolymer

Source: Acta Physica Polonica A

Year : 2005

Abstract:

Nuclear magnetic resonance, broadband dielectric spectroscopy and dynamic-mechanical thermal analysis were employed to study molecular dynamics of ethylene-norbornene copolymer. The analysis of experimental data indicates existence of three motional processes denoted as α, β, and γ in order of decreasing temperature. The α relaxation is related to the dynamic glass transition, while the beta relaxation, observed only for the untreated sample, is assigned to short range segmental motions involving norbornene units. The γ relaxation is due to very local motions of ethylene units e.g. trans-gauche isomerization, similar to those responsible for γ relaxation in polyethylene. The rate of motion accountable for γ process, follows the Vogel-Fulcher-Tammann equation, similarly to alpha transition, indicating cooperative nature of the motion.

DOI: 10.12693/APhysPolA.108.385   (Pobrane:  2021-01-10)