a method of manufacturing polymeric material having enhanced structural integrity includes heating the material to a temperature between the material &# 39 ; s glass transition temperature and the material &# 39 ; s melt temperature . once heated , the material is highly overstretched in a first direction and moderately overstretched in a second direction . the material is then held in the overstretched condition while it is allowed to cool to room temperature . cooling is followed by reheating to a curing temperature . after curing for a predetermined period , the material is again allowed to cool . the completed material has high polymeric orientation in the first direction and moderate polymeric orientation in the second direction . therefore , the material is characterized by enhanced structural integrity and absence of pinhole defects common to highly oriented polymeric materials .