1. Enzymatic recycling of polyethylene terephthalate through the lens of proprietary processes
José L García Microb Biotechnol. 2022 Nov;15(11):2699-2704. doi: 10.1111/1751-7915.14114. Epub 2022 Jul 20.
Because society is doing significant efforts to recycle plastics, one option is to break them down into monomers with the help of specialized enzymes. Polyesters such as PLA (polylactic), PCL (polycaprolactone), PHAs (polyhydroxyalkanoates) and PET (polyethylene-terephthalate) have been considered in more detail for these biological treatments, because they can be now produced as bio-based polymers, and because ester bounds and esterases are very frequently found in nature. In particular since PET is the most abundant thermoplastic of the polyester family and accounts for approximately 10% of all synthetic plastics on the market, it has attracted more attention. Here we will review the patented biological recycling processes concerning the recycling of PET.
2. Synthesis of hydantoins via N,N'-ureas derived from polymer-bound amino acids
M Bauser, M Winter, C A Valenti, K H Wiesmüller, G Jung Mol Divers. 1997;3(4):257-60. doi: 10.1023/a:1009639804397.
Starting from carboxy-linked amino acids on trityl functionalized polystyrene resin a highly efficient solid-phase synthesis of hydantoins via N,N'-ureas was elaborated. The polymer-bound hydantoins can be used as a scaffolds for further combinatorial transformations, such as alkylation. Cleavage from the resins yielded the corresponding hydantoins in good yields and purities as shown by ESI-MS and HPLC.
3. An Aromatic Fluoropolymer for Hydrogen Separation from Hydrocarbons
Jian Guan, Yanqiu Lu, Lijun Du, Canzeng Liang, Ji Wu, Dongfei Li, Sui Zhang Macromol Rapid Commun. 2022 Mar;43(6):e2100796. doi: 10.1002/marc.202100796. Epub 2022 Jan 22.
Plasticization is a critical challenge in membrane-based gas separation. Here a novel fluoropolymer, poly(trifluoro styrene) (PTFS), is reported for hydrogen separation from hydrocarbons. The polymer structure is first characterized by different techniques such as nuclear magnetic resonance (NMR) and positron annihilation lifetime spectroscopy (PALS). Then, gas separation performances of the polymer are studied. The separation of H2 /CH4 is found to outperform most other fluorinated polymers and surpass the Robeson 1991 upper bound. Furthermore, the polymer demonstrates stable or increasing selectivity for hydrogen over hydrocarbons (e.g., CH4 , C2 H6 , and C3 H8 ) at higher pressure, suggesting excellent resistance to plasticization.
