Tensile drawing behaviour of polyethylene terephthalate



A wide range of polyethylene terephthalate fibres was prepared by melt spinning to different degrees of molecular orientation. The tensile drawing behaviour of these fibers was then studied, either by drawing over a heated cylinder at 85°C or by drawing over both a heated cylinder and a plate at 180°C. The mechanical properties and structure of the subsequent drawn fibres are discussed in terms of the network draw ratio, determined by matching true stress–strain curves for the drawn and initial melt spun fibres. It is shown that this procedure provides valuable insight into subtle differences in properties and structure that can arise from differences in processing routes.