Temperature and torsion strain analysis of the dynamical visco-elastic properties of high-density polyethylene

The behaviour of the dynamical visco–elastic functions in high–density polyethylene (HDPE), which carries the trade mark 'Bulen', in the region of gamma and beta relaxation transitions has been studied. The method of forced torsion vibrations was used to obtain the curves for the storage modulus (G'), loss modulus (G′), loss modulus (C″) and loss tangent (tgδ) in the temperature interval (–180 to + 20)°C and torsion strain (0.01 to 1.2)%. The loss functions show extremes at torsion strain S = 0.1% for the gamma relaxation transition and at S = 1.0% for the beta relaxation transition, which are explained with reference to the processes of the deformational orientation of the macromolecular chain segments, change in the micro–Brownian macromolecular mobility, the degree of anelastic intermolecular interactions, etc. The scanning electron microscopy (SEM) study shows a strong integration of the segments of the macromolecular chains into sublevels of the superstructural molecular organization and at the same time local co–operation of the sublevels.