Crystallization from an Oriented Amorphous State

Polymer crystallization under flow or under highly oriented states is of prime importance in industrial polymer processing. We expected that the crystallization would be highly accelerated when the initial amorphous chains were highly orientated. Therefore, we dared to use a realistic molecular model of 

the united atom model. We considered a sufficiently long PE chain made up of 5000 united atoms under periodic conditions in each direction. The initial amorphous sample prepared at 600 K was quenched to 100 K and drawn up to 400%. The sample was then quickly heated to various crystallization temperatures, and the molecular processes of fiber formation were monitored in situ via the real-space image and its Fourier transform, the structure function S3d( j) defined as follows  

Here we averaged the structure function S3D(q) around the draw axis to give S2d( 2 q ), where q and q are the components of the wave vector along the draw axis and perpendicular to it, respectively. 

Typical snapshots and the structure functions at 350 K are shown in Fig. 39. In the initial state at 0.1 ns, we see two intense peaks on the meridian at q = 52 nm-1 and on the equator q = 14 nm-1, where the peaks correspond to half the fiber period of PE and the nearest neighbor inter-chain 

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