Plastic deformation in linear polyethylene

A detailed study has been made of drawn linear polyethylene using vibrational spectroscopy. The proportion of a monoclinic crystal modification and its dependence on draw ratio is determined by draw temperature, rate and medium (air or water). This is explained by the role of mechanical energy increasing local temperatures within the samples and the corresponding loss of heat to the environment. Monoclinic material acts as a sensitive molecular level thermometer and indicates that temperatures in the vicinity of the melting point can be generated by drawing.