heat sealing temperature and high clarity as well as improved processability are simultaneously achieved in these films application_number US 77091185 A description polybutylene 1 when subjected to certain chemical agents such as peroxides under appropriate conditions undergoes a special type of degradation sometimes known as cracking which is random scission of the polymer molecules the process is comparable to that undergone by other polymers particularly polypropylene a basic concept of accomplishing such degradation by utilizing peroxides is claimed in u s pat no 3 144 436 where a free radical initiator is introduced into a polymer melt in the absence of oxygen in a screw extruder u s pat no 3 940 379 discloses a method for the degradation of propylene polymers to increase their melt flow rate which comprises contacting a propylene polymer with oxygen and an organic or inorganic peroxide melting and working the resulting mixture in a high shear zone and recovering an essentially odor free propylene polymer u s pat no 4 061 694 discloses the manufacture of polypropylene molding compositions of improved impact strength by subjecting block copolymers of ethylene and propylene to controlled oxidative degradation under conditions essentially similar to those of the preceding patent other patents dealing with degradation of polypropylene include u s pat nos 4 375 531 3 862 265 3 887 534 3 898 209 4 001 172 4 087 486 4 359 495 4 378 451 and 4 387 185 the extent of such random scission is governed by the amount of chemical agent present fig1 shows the molecular weight distribution mwd of reactor polybutene 1 pb 8a with a melt index of 0 84 dg min also.