The effect of polypropylene morphology on AC breakdown

It is well known that when a crystallizable polymer is solidified from a solution or a melt, a wealth of physical structures can be obtained depending on the processing conditions. In addition, the structures so obtained can be further altered by additional steps such as drawing and annealing. Consequently, polymeric solids exhibit a range of values for the same physical property, a behavior which is quite unlike that observed with low molecular weight solids. This, therefore, offers the possibility of modifying a material's physical properties by changing its physical structure. The property of interest here was the AC breakdown strength and the polymer used was isotactic polypropylene.