Modeling of Time-Dependence in Ultra-High-Modulus Polyethylene Based on Raman Microscopy

Previous research dealt with the modelling of time dependence in ultra-high-modulus polyethylene in terms of mechanical systems. Although such attempts were highly successful in describing time-related phenomena in melt-spun polyethylene, they were less able to account for the behaviour of gel-spun material. Moreover, in the early experiments, only the macroscopic deformation could be determined. Recent advances in Raman microscopy have enabled a study of the changes in internal strain associated with crrep and recovery. This short paper considers some preliminary creep data in terms of mechanical models which, despite their simplicity, are nevertheless able to provide a phenomenological basis for a number of the observed features: most notably the attainment of a strain maximum in one of the differently stressed structural components.