a specific class of thermoplastic polymers with improved processability resulting from initial partial degradation of high molecular weight polymers using a chemical prodegradant present in excess of the amount reacted during pelletization . this class of polymers includes polymers and copolymers of polypropylene and butylene . after pelletizing , the polymer including unreacted prodegradant can be safely handled and shipped without difficulty . when remelted by extruding or the like , the prodegradant in the pellets reacts , further reducing the molecular weight as well as narrowing the molecular weight distribution of the polymer to a point where high capacity production of quality fibers and extruded products can be obtained . the prodegradant is preferably of the type that predictably and controllably affects the polymer molecular properties without being significantly affected by minor fluctuations in the polymer producer &# 39 ; s or processor &# 39 ; s manufacturing steps . specific preferred embodiments include 2 , 5 - dimethyl - 2 , 5 bis - hexyne - 3 ; 3 , 6 , 6 , 9 , 9 - pentamethyl - 3 -- 1 , 2 , 4 , 5 - textraoxy cyclononane ; α , α &# 39 ;- bis diispropyl benzene and 2 , 5 - dimethyl - 2 , 5 - di hexane as the prodegradant added in an amount providing an amount of unreacted prodegradant after pelletizing of about 0 . 01 to 10 . 0 percent based on the weight of polymer . the present invention reduces the safety hazards present when handling free radical prodegradants by the polymer processor and avoids the need for multiple addition of prodegradants while still producing a material that can be processed easily by the polymer producer and processor .