MacroCycle, a spin-out of the Massachusetts Institute for Technology (MIT), has raised $6.5 million in seed funding.
The company uses an untypical technology to recycle PET waste: ring-opening polymerisation (ROP). Usually, ROP is a polymerisation process that synthesises polymers from cyclic monomers. It typically involves opening the ring structure of a monomer and linking the resulting open-chain units into a polymer. However, PET’s monomers, terephthalic acid (TPA) and ethylene glycol (EG), are linear molecules.
The workaround is to target PET’s macrocyclic oligomers, MacroCycle’s co-founder and CTO Dr. Jan-Georg Rosenboom told Sustainable Plastics. Oligomers are molecules consists of repeating units derived from monomers. PET’s oligomers can have more than 10 repeat units, making them macrocyclic structures, Rosenboom explained.
MacroCycle’s process opens the ring structure of PET’s oligomers and links the resulting open-chain units into PET. By increasing the length of the polymer chains, the process increases rPET’s intrinsic viscosity (IV), making it more durable and stretchy.
“Our final product is linear virgin-grade PET. We are using the macrocyclic oligomers only as intermediates to convert the PET waste with non-toxic reagents, before isolating them through various proprietary means and converting them back to linear form with Ring-Opening Polymerisation. The result is IV upgraded pure PET,” Rosenboom explained.
The process uses temperatures ‘significantly lower’ than PET’s melting point of 250 C, Rosenboom said, and does not apply additional pressures. It can use various commercially available catalysts, including those standardly used in PET depolymerisation.
As a consequence, MacroCycle’s technology requires up to 80% less energy than fossil-based PET production, and at least 50% lower capital expenditure than competing chemical or biologic recycling methods, the company said in a statement.
“There’s a $700 billion linear plastics market opportunity, but today’s recycling technologies are too expensive to build and operate and still yield low-value products. Our technology provides a more efficient process to produce high-quality plastic that can be adopted as a drop-in solution and which is competitive with fossil fuel-based plastic,” said MacroCycle CEO Stwart Pena Feliz. “Our technology will be a key enabler for plastic circularity, as we allow our customers and suppliers to finally unlock the economic and environmental benefits of recycling.”
The groundwork for MacroCycle’s technology was laid during the academic work of Rosenboom and his colleagues at MIT, ETH Zurich, and Politecnico Di Milano. With early support from the Bill Gates’ Breakthrough Energy Fellows programme, MacroCycle has already scaled up its technology 100 times from lab-scale beakers to a pilot plant reactor running at the Engine Accelerator’s facilities in Massachusetts, United States.
The company plans to use the funding to grow operations and scale its pilot plant, which currently processes about 5 tones of PET waste per year on a 24/7 operational basis.
It will look to recycle PET bottles and polyester textile waste from customers across the cosmetics, textiles, home goods, food and beverage industries, as well as luxury and fast fashion clothing brands. MacroCycle’s pilot plant will support large-scale product validation and produce the first bottles and garments made entirely from its recycled PET resin.
The funding round was led by venture capitalist funds Clean Energy Ventures and Volta Circle, the investment firm backed by Indorama Ventures. KDT Ventures and Neotribe Ventures also participated.