Dr Jon Husband led the research at the University's Institute of Sustainability and Climate Change.
Photo Credit: Courtesy of University of Bath
Scientific Frontline: Extended "At a Glance" Summary: Endless Acrylic Plastic Recycling
The Core Concept: Researchers have developed a novel chemical recycling method for polymethyl methacrylate (PMMA, commonly known as acrylic or Perspex) that breaks the plastic down into its original monomer building blocks without degrading the material's quality.
Key Distinction/Mechanism: Unlike conventional mechanical recycling, which degrades optical clarity, or standard chemical pyrolysis, which requires extreme heat (350-400 °C) and is highly susceptible to contamination, this new method utilizes UV light under oxygen-free conditions at significantly lower temperatures (120-180 °C). Furthermore, it avoids the toxic, chlorinated solvents used in other recent UV-activated depolymerization methods, utilizing sustainable alternatives instead.
Major Frameworks/Components:
- UV-Driven Depolymerization: Utilizes ultraviolet light in an oxygen-free environment to chemically "unzip" consumer-grade PMMA back into its base monomers.
- Low-Temperature Processing: Operates efficiently between 120-180 °C, drastically lowering the energy requirements compared to traditional pyrolysis.
- Sustainable Solvents: Employs non-chlorinated, environmentally friendly solvents, ensuring the process remains non-toxic and industrially viable.
- High-Yield Recovery: Achieves over 95% conversion of the plastic waste and yields more than 70% pure monomer, which can be purified and repolymerized into "as new" materials.
Branch of Science: Polymer Chemistry, Materials Science, and Green Chemistry.
Future Application: Currently capable of recycling small batch amounts, the process is being developed for industrial-scale, closed-loop recycling. It aims to handle the roughly 3 million metric tons of acrylic used annually worldwide, allowing it to be continuously remade into pristine, glass-like products such as automotive components, digital screens, and eyewear.
Why It Matters: This technology offers a viable pathway to true circularity in plastic manufacturing. By directly overcoming the twin hurdles of prohibitive energy costs and low-quality recycled outputs, it ensures that high-value transparent plastics can be endlessly recycled rather than eventually relegated to landfills or incineration.
A breakthrough method for chemically recycling acrylic - one of the world’s most widely used plastics - has been developed by researchers at the University of Bath.
In contrast to conventional mechanical recycling, this method uses lower temperatures and sustainable solvents without losing material quality, meaning the plastic can be recycled many times over with minimal environmental impact.
Acrylic, sold under the brand names including Perspex and Plexiglas, is made from the transparent thermoplastic polymethyl methacrylate (PMMA).
Approximately 3 million tons are used worldwide each year, in a wide range of applications including automotive components, screens and construction materials.
The work, published in Nature Communications, was led by Dr Jon Husband and Dr Simon Freakley from the University’s Institute of Sustainability and Climate Change (ISCC) and co-authored by the Innovation Centre for Applied Sustainable Technologies (iCAST) Director Professor Matthew Davidson.
"With current methods for recycling both energy intensive and inefficient, the demand for cleaner, more efficient recycling technologies has never been greater.
Plastic recycling can be tough to make economically feasible, due to issues around high energy costs and low-quality product; this work directly addresses both issues."
The Perspex problem
Mechanical recycling is the most common recycling method, which can involve shredding or melting the plastic to reform pellets for new uses. However, this leads to discoloration and a gradual decline in quality, meaning the recycled material can no longer be used for glass-like applications like screens or spectacles.
Recent industry focus has been on pyrolysis - the heating of Perspex to 350-400 °C - to turn the plastic back into its monomer building blocks to be made from scratch again, in pristine quality. However, this process is very energy-intensive and is easily contaminated by other plastics.
A cleaner, safer way to “unzip” acrylic plastics
The new process developed by the team at Bath uses UV light under oxygen-free conditions to chemically break down consumer-grade PMMA plastic into its original monomer building blocks.
Crucially, the chemistry works at 120-180°C, far below the 350-400°C typically needed for conventional pyrolysis-based recycling.
This significantly lowers the energy input needed, improving both environmental performance and commercial scalability.
High yields suitable for true circularity
The new approach delivers over 95% conversion of the plastic and yields more than 70% monomer, which can then be purified and repolymerized into “as new” materials.
"Developing new chemical recycling approaches matters because it turns waste back into pristine new materials, rather than a lower grade, low-value material destined for eventual disposal.
This method allows us to recover high-quality monomers from used PMMA, offering a clear pathway toward genuine circularity in acrylic materials."
Scalable, sustainable plastics recycling
The Bath team’s discovery advances beyond a concurrent discovery in PMMA recycling from researchers at ETH Zurich, which relies on UV activated chlorinated solvents to drive depolymerization.
In contrast, the Bath team’s process is compatible with more sustainable solvents, opening the door to greener, simpler, and more industrially viable recycling routes.
Currently, the team can recycle a few grams of real plastic waste at a time. Research is ongoing to improve efficiency and scale the process.
Published in journal: Nature Communications
Authors: Jonathan T. Husband, Gavin Irvine, Callum R. Morris, Andrea Folli, Matthew G. Davidson, and Simon J. Freakley
Source/Credit: University of Bath
Reference Number: chm040226_01