Plastics contain various additives, such as dyes and fillers, which result in loss of material performance or aesthetics after recycling. A new recyclable plastic developed at U.S. Lawrence Berkeley National Laboratory (LBNL) can be disassembled into its constituent parts at the molecular level, and then repeatedly reassembled A mixture of red, blue, yellow and black PDK plastic was depolymerized (left) and then separated to yield a solid mixture of PDK monomers and pigments/additives (right). Source: LBNLinto a different shape, texture and color without loss of performance or quality.

Reversible polymerization of plastics during recycling allows high-value monomers to be recovered and re-manufactured into pristine materials, but monomer recovery is cost- and energy-intensive. The new poly(diketoenamine), or PDK, formulation enables recovery of monomers from common additives, even in mixed waste streams. Recovered monomers can be re-manufactured into the same polymer formulation, without loss of performance, or into other polymer formulations with differentiated properties.

Unlike conventional plastics, the monomers of PDK plastic could be recovered and freed from any compounded additives by treating the material with a highly acidic solution. The acid helps to break the bonds between the monomers and separate them from the chemical additives that give plastic its physical properties.

The researchers say that PDK could be used to help close the plastics recycling loop and plan to develop PDK-based plastics for textiles, 3D printing and other applications.