Annealing effect on cold drawing of PVC-films

Cold drawing of PVC-films at room temperature depends on thermal pretreatment. Yield stress, difference between yield and draw stress and neck temperature increase, when the samples have been annealed not far below glass transition temperature and subsequently quenched; they decrease by annealing aboveT_g and quenching down to room temperature. These changes of variables characterizing the cold drawing process can be interpreted morphologically by an increase or decrease of free volume in the noncrystalline regions which favour neck formation or render it more difficult respectively.