Fully lignocellulose-based PET analogues for the circular economy

Area of Science:

• Polymer Chemistry
• Green Chemistry
• Biomass Valorization

Background:

• Polyethylene terephthalate (PET) is a widely used polymer but a significant environmental pollutant.
• There is a critical need for sustainable and recyclable alternatives to conventional plastics.
• Woody biomass offers a renewable resource for developing novel materials.

Purpose of the Study:

• To create readily recyclable polyethylene terephthalate analogues from woody biomass.
• To develop a catalytic process for converting lignin into valuable chemical building blocks.
• To synthesize and characterize novel polyesters with competitive properties and recyclability.

Main Methods:

• A two-step, noble metal-free catalytic process involving reductive catalytic fractionation and catalytic funneling.
• Isolation of the aliphatic diol 4-(3-hydroxypropyl) cyclohexan-1-ol from lignin.
• Co-polymerization of the diol with methyl esters derived from cellulose residues (terephthalic acid and furan dicarboxylic acid).

Main Results:

• High isolated yield (11.7 wt%) of 4-(3-hydroxypropyl) cyclohexan-1-ol from lignin.
• Total carbon yield of 29.5% including conversion of other streams to fuels.
• Synthesized polyesters with competitive molecular weights and glass transition temperatures (Tg) of 70-90°C.
• Demonstrated excellent chemical recyclability in methanol.

Conclusions:

• Novel, readily recyclable polyethylene terephthalate analogues can be produced entirely from woody biomass.
• The developed catalytic process efficiently converts lignin into a key diol monomer.
• These bio-based polyesters show promising properties and recyclability, making them suitable for the circular economy.