Applications:
- Waste management for plastic products
- Efficiently convert plastic waste into new chemicals
- Optimize sustainable supply chains for chemical companies
Advantages:
- Reduced energy consumption by using lower temperatures
- Increased reliability ensures consistent quality of recycled materials
- Effectively handles mixed plastic streams in a single process
- Lower impact of contaminants (in the end-of-life product) on the process
Background:
Current recycling processes for plastics have high energy requirements, and only 5-9% are recycled effectively. Each recycling cycle leads to oxidative degradation and structural changes in plastic material due to exposure to high temperatures. This degradation diminishes the quality of the recycled product, limiting its usability and lifespan. As a result, many plastics are recycled only a few times before they become unusable. The economics of recycling are also unprofitable, making it a non-viable solution. A dissolution process under milder conditions is a feasible alternative.
Technology overview:
JBEI researchers have developed a technology for reusing synthetic plastics while minimizing energy requirements and eliminating the use of harsh chemicals. The process is halogen-free and utilizes biocompatible solvents like amines produced by actinobacterias. Synthetic plastics undergo dissolution and depolymerization under mild conditions and at room temperature (and/or lower temperatures), breaking down the long-chain polymer molecules into monomeric units. The process prevents the degradation of material quality observed in traditional recycling methods and creates the opportunity to repurpose these monomers for the production of new high-quality plastic products.
Experimental results show up to 95% depolymerization of PET achieved in ethylenediamine at room temperature. PET was soluble in other solvents to a lesser degree, achieving 92% isolated yield of the water-soluble product N,N-bis(2-aminopropyl)terephthalamide at room temperature in 1,3-propanediamine. Water solubility with the addition of JBEI solvents extended to a wide range of synthetic plastics, including those commonly found in consumer products and packaging materials (PUR, PC, PS, PP, LDPE, and HDPE). PC was observed to be completely soluble in ethylenediamine, while PUR had limited solubility. Plastics with C-C backbone (PP, PS, and PE) had limited solubility in ethylenediamine at room temperature.
Commercial plastic blends that were tested (PP, polyesters, and polyamide) achieved ~20% mass loss in water-soluble amide products. This makes the solution highly adaptable for various industries and applications, as it can be used to sort and separate C-C- backbone plastics from polyesters, polycarbonates, etc. Researchers are working to further optimize the reaction coordinates, offering a viable path to sustain the plastic industry while significantly mitigating its environmental impact.
Development Stage: Laboratory Scale
Principal Investigators:
- Hemant Choudhary
- John Gladden
- Seema Singh
- Blake Simmons
Status: Patent Pending