THE SYNTHESIS OF LOW-MOLECULAR WEIGHT HYDROXY-TIPPED POLYETHYLENE AND POLYPROPYLENE BY THE INTERMEDIACY OF ZIEGLER-NATTA CATALYSTS

The use of diethylzinc in conjunction with conventional and supported Ziegler-Natta catalysts permits the synthesis of polypropylene and polyethylene samples with g. p. c. M OVER BAR //n values as low as 4000 and 3000 respectively. At high diethylzinc concentrations the number of metal-polymer bonds appears to be 40% for polypropylene and 50% for polyethylene respectively, as measured by a tritium-quench radiotracer method. The metal-bound macromolecules can be efficiently oxidized with molecular oxygen at 60 degree C, and subsequently hydrolyzed to give hydroxy-tipped polymers. The oxidation efficiency appears to be variable and to be lower at high diethylzinc concentrations.