High CarbonRecovery in Photocatalytic Degradationof High-Density Polyethylene (HDPE): Blend with Stearic Acid as aRadical Source

A blend of high-density polyethylene (HDPE, <i>M</i>_w = 59.4 kDa) and stearic acid was efficiently degraded under cerium catalyzed photodecarboxylation conditions, and the molecular weight decreased to <i>M</i>_w = ∼5 kDa. The reaction proceeds at 100 °C in <i>tert</i>-butylnitrile (^<i>t</i>BuCN) in air, where HDPE does not dissolve or swell. The products are solid material with >90% weight recovery of the starting HDPE + stearic acid. Control experiments supported that carbon radicals generated by cerium-catalyzed photodecarboxylation of stearic acid transferred to the main chain of the HDPE, which undergoes oxidative degradation to lower the molecular weight.