Centrifugal partition chromatography approach to separate additives from PVC resin to support recycling processes

Plastics are widely used materials composed of polymers and various additives to achieve specific properties. Their composition is often highly complex, particularly in post-consumer plastic waste. As mechanical recycling faces increasing limitations, chemistry-driven strategies are attracting growing interest to improve plastic recovery. Among these, dissolution recycling offers the possibility of selectively recovering pure polymers free from additives and contaminants. However, the absence of efficient methods to separate and analyze the different components of plastics remains a major bottleneck to evaluate recycling processes effiency. Here, we report the first application of Centrifugal Partition Chromatography (CPC) to address this challenge using polyvinyl chloride (PVC) as a model material. A biphasic solvent system based on heptane, dimethyl sulfoxide (DMSO), and 3-pentanone (DEK) (25/45/30 w/w/w) was developed, guided by Hansen solubility parameters. CPC enabled the separation of the polymer from organic additives and contaminants, as well as the fractionation of additives into distinct groups, facilitating their subsequent identification and potential quantification. Moreover, CPC allows the recovery of sufficient amounts of purified polymer, enabling detailed spectroscopic characterization to assess its structural integrity and purity. After fractionation, additives were identified by reverse phase liquid chromatography coupled with tandem high resolution mass spectrometry (RPLCHRMS/MS), while the recovered polymer was analyzed using nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). Overall, these results demonstrate that CPC is a promising tool to fractionate complex plastic matrices, offering new opportunities for advanced material characterization and supporting the development of more efficient recycling processes.