Structure formation in a crosslinked polyethylene melt crystallizing under uniaxial tension

The formation of supermolecular structure has been investigated in the case of medium-pressure polyethylene film subjected to a dose of 30 Mrad of n, γ radiation. The melt, prestretched at 160°C to various degrees of elongation α, was crystallized at constant temperature. The results are interpreted on the basis of an analysis of the effect of the mechanical field on the growth kinetics and the orientation relative to the direction of extension of the individual crystallites; the first factor determines the shape and the second the sign of the spherulite.