Observation of Relaxation Mechanisms of Crystalline Polymers by Electron Microscopy

Abstract

Relaxation mechanisms of crystalline polymers have been clarified directly by electron microscopy. In polyethylene, the “main dispersion” which is due to the micro Brownian motion of the main chain in the amorphous phase and the “grain boundary dispersion” for the time scale of one hour can be attributed to the motion of chains in the boundary region betweeen spherulites and the slip lamellae in a spherulite, respectively. In polychlorotrifluoroethylene the slip of lamellae in a spherulite with the time scale of one hour appears above the temperature region of the “main dispersion”. This indicates that the “grain boundary dispersion” coexists with the “main dispersion”. In polytetrafluoroethylene, the main fraction of the “crystalline dispersion” (β dispersion) is regarded as the “grain boundary dispersion” which is due to the slip of striations within the band.