Plastics are a key component of virtually any technology today. Although their production consumes enormous feedstock resources, plastics are largely disposed of after their useful service life. In terms of a circular economy, 1-8 desirable re-utilisation of post-consumer sorted polymers ('mechanical recycling') is hampered by deterioration of materials performance. 9,10 Chemical recycling 1,11 via depolymerisation to monomer offers an alternative to retain high performance properties. The linear hydrocarbon chains of polyethylene 12 enable crystalline packing and provide excellent materials properties. 13 Their inert nature hinders chemical recycling, however, necessitating temperatures > 600 °C and recovering ethylene with < 10 % yield. 3,11,14 Here, we show that renewable polycarbonates and polyesters with a low-density of in-chain functional groups as break points in a polyethylene chain can be recycled chemically by solvolysis with > 96 % recovery. At the same time, the break points do not disturb the crystalline polyethylene structure, and the HDPE (high density polyethylene)-like materials properties are fully retained upon recycling. Processing can be performed by common injection moulding and the materials are well-suited for additive manufacturing. Selective removal from model polymer waste streams is possible. The virgin polymers result from polycondensation of long-chain building