KINETIC-MODEL FOR TENSILE DEFORMATION OF POLYMERS .5. EFFECT OF TEMPERATURE ON ORIENTATION EFFICIENCY

A previous molecular model for tensile deformation of polymers is exte nded to include the effect of temperature on the development of orient ation during drawing of flexible polymers that are characterized by we ak intersegmental interactions, such as polyethylene. The results obta ined confirm the experimentally observed existence of a maximum drawin g temperature above which the efficiency of the orientation process de creases, presumably due to disentangling and recoiling of the polymer chains. This maximum temperature is predicted to increase linearly wit h (the logarithm of) the weight-average molecular weight. Polydispersi ty was found to significantly decrease the efficiency of drawing at hi gh temperatures.