Influence of the Strain Stress on the Glass Transition in Partially Crystalline Polyester Filaments

There are present part of the new experimental results obtained in the frame of a large scale studying of the influence of heat mechanically treatment parameters on the structural development in partially crystalline poly (ethylene terephthalate) (PET) yarns. It is investigated the influence of the strain stress on the filaments glass transition. The samples heat mechanical treatment was realized at isothermal conditions at temperature of 80 0С, close above the fibers glass transition temperature and under applied constant strain stress. The processed fibers were subjected to structural analyses using differential scanning calorimetry (DSC). There is established relationship between the applied strain stress values and the running of samples relaxation transition.