July 30, 2024

Regenerated MMA Through Next-Gen Acrylic Recycling

By Jean-Luc Dubois, Principal Scientist at Trinseo

Society relies on plastics for our most demanding applications. Whether lightweighting vehicles for fuel efficiency or delivering durable and sanitary medical devices, plastics are intrinsically connected to our technological evolution. They are valuable materials that cannot be replaced. However, with millions of tons of plastics produced worldwide each year for essential applications, we must find more sustainable alternatives for handling disposal.

Plastic waste has become a leading concern worldwide, prompting regulators and industry organizations to focus on developing a circular economy. Recent regulations in Europe include the European Green Deal and forthcoming end-of-life vehicle directive, as well as others in North America and Asia. At the same time, industry organizations are focused on building the infrastructure for a circular economy that can work alongside these new regulations. In 2023, Plastics Europe announced its Plastics Transition report, providing a roadmap for plastics in Europe to be circular by 2050.

Trinseo’s sustainability strategy aligns with this roadmap, and the company is focused on helping customers meet forthcoming mandatory targets for recycled content containing plastic solutions. As part of the company’s 2030 Sustainability Goals, Trinseo continues to expand its sustainably advantaged product portfolio by investing in circular technologies and R&D initiatives. Just one way the company has approached circular solutions is through developing complementary recycling technologies.

Mechanical, Physical, Chemical Recycling

Recycling enables society to recapture the value of plastics once they reach their end of life. Historically, mechanical recycling has been the preferred method for processing plastic wastes.1 In this approach, waste materials are processed, sorted, and treated/cleaned before they undergo grinding and compounding. This method enables the material, to some extent, to maintain its chemical structure and original color.

Physical recycling, or selective dissolution, has gained industry interest for several polymers as it enables a broader acceptance of waste. This recycling method can be used alongside mechanical recycling because it only impacts targeted polymers within the waste stream. Similar to mechanical recycling, dissolution preserves the molecular weight of the polymer, and, in some cases, the process can yield nearly 100% material recovery.

However, there are some limitations to these technologies. First, undesired legacy additives and inhibitors, as well as polymeric impurities, are not removed during the recycling process.1 For plastics developed to last years or even decades, this can mean they will not be recyclable at their end of life. This can be seen in the automotive industry, where vehicles are designed to be on the road for decades. Regulations change much faster than vehicles reach their end of life, and so plastics in older vehicles might contain chemicals that have since been banned. Mechanical and physical recycling technology cannot always remove these additives and contaminants. Materials containing color dyes can only be processed for use in all black and dark applications; those containing unwanted chemicals are disposed of through landfilling or incineration.

Second, mechanical recycling also poses limitations based on the type of material being processed. All plastics are limited in the number of cycles the material can be processed through mechanical recycling, but some solutions—such as polymethyl methacrylate (PMMA) cast sheets— deteriorate during the first process cycle and the polymer cannot be recovered.

Chemical recycling can address these issues. A family of recycling techniques, chemical recycling—also known as advanced recycling in the U.S.—utilizes methods like pyrolysis (heat treatment in the absence of oxygen) and solvolysis (reactive treatment in the presence of a chemically active agent) to return the material to its original molecular form.

PMMA in its various forms (cast sheets, extruded sheets, and resins) can be recycled through depolymerization, a chemical recycling technology that regenerates methyl methacrylate (rMMA). Research shows that within the chemical recycling processes, depolymerization is the most sustainable option because, in theory, there is no limitation to the recyclability of the solution in a closed-loop* system since it is returned to the monomer and further purified.¹

By investing in technologies like mechanical and chemical recycling, Trinseo can support customers with a variety of acrylic solutions that contain recycled content. With well-known brands on the market such as ALTUGLAS™, PLEXIGLAS®, and AVONITE™, Trinseo can help an array of industries exploring the transition to more circular acrylic solutions. Trinseo manufactures rMMA-containing PMMA under its R-Life product portfolio, a family of acrylic resins and cast sheets that are made with a minimum of 50% chemically or mechanically recycled feedstocks. By utilizing complementary recycling technologies for portfolios like R-Life acrylics, Trinseo can maximize waste feedstocks and maintain consistent quality.

Trinseo’s Depolymerization Technology

PMMA is known for its transparency, durability and performance properties, making it intrinsic to daily life via automotive, medical and consumer goods applications.

While acrylic was one of the most sought-after polymers in the world during the COVID-19 pandemic,² PMMA and its monomer represent a very small percentage of the market share for plastics.³ PMMA remains in demand; the material is poised to have a compound annual growth rate (CAGR) of 5.5% during the forecast period 2023 to 2032, with market value expected at $8.33 billion at the end of this period.⁴

With over 300,000 tons of PMMA produced in Europe per year, PMMA has significant growth opportunities for recycling.² Research shows that each year, 10% of produced acrylic materials end up as post-production collected waste, but as much as 90% ends up as post-consumer waste.² With continued market demand and forthcoming regulations around the export of waste streams outside of Europe, Trinseo sees an opportunity to remove valuable, recyclable feedstocks from those waste streams that would otherwise be landfilled or incinerated. Through depolymerization, these end-of-life acrylics can be utilized to supply consistent, quality rMMA-containing feedstocks that can support sustainably advantaged innovation.

Trinseo, along with its recycler, Heathland B.V., were members of the MMAtwo consortium, a chemical industry organization funded by the European Union’s Horizon 2020 research and innovation program to develop a new value chain for PMMA waste and a new technology process for recycling it into high-quality regenerated monomers. The research conducted by the consortium has been instrumental in moving the industry forward with chemical recycling. MMAtwo evaluated 11 depolymerization technologies that exist at 24 sites worldwide to understand the most effective and efficient way of processing acrylic wastes—even the most challenging streams. The consortium identified the twin-screw extruder process for depolymerization as the most advantageous.⁵ This process, which is a variation of the dry distillation method, utilizes a plug flow stirred reactor so that the heat transfer can be pushed to the maximum.⁵ Through Trinseo’s collaboration within MMAtwo, it has been able to deliver a next generation depolymerization value chain and technology utilizing an advanced twin-screw extruder process to generate high purity rMMA.

With a PMMA depolymerization plant in Rho, Italy, the company can produce rMMA that achieves high purity levels and is comparable to virgin raw materials. This enables use in similar applications, including taillights or caravan windows that require high optical quality.

In addition to rising demand for acrylics, MMA is also experiencing significant market demand, growing at a forecasted CAGR of 5.8% from 2024 to 2033, with an estimated market worth of $14.2 billion at the end of this period.⁶ With such a growing demand, the ability to supplement high purity, sustainable rMMA instead of its virgin counterpart could have a massive impact on industries such as building and construction, consumer electronics, consumer goods, and possibly even medical. 

Additionally, results of a study conducted by MMAtwo shows that of the facilities the consortium evaluated, those utilizing depolymerization technology had at least a 70% reduced carbon footprint compared to facilities producing virgin MMA.⁵ This means that implementing rMMA as a replacement for its virgin counterpart can have a significant impact on the environment as well.

As a global supplier of innovative PMMA solutions, Trinseo is well positioned within the value chain to leverage its expertise in manufacturing and work with its global network through Heathland to deliver its rMMA-containing acrylic solutions.

By investing in innovative circular technologies, Trinseo can deliver products that continue to provide design freedom while keeping the planet in mind. The company’s depolymerization technology generates a high purity monomer that can be used to produce rMMA-containing resins and sheets, which have equivalent properties to their virgin counterparts. This provides designers and brand owners with a sustainably advantaged option that does not sacrifice aesthetics and design, but still helps them advance their sustainability goals.

As regulations continue to change and companies seek a partner to help them transition, Trinseo’s investment in complementary recycling technologies can help ease the move toward rMMA-containing solutions.

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¹ J. De Tommaso, F. Galli, R. Weber, J.-L. Dubois, G. S. Patience, ChemSusChem 2024, e202301172. https://doi.org/10.1002/cssc.202301172

² J. De Tommaso, J.-L. Dubois, Risk analysis on PMMA Recycling Economics. Polymers 2021,13(16), 2724. https://doi.org/10.3390/polym13162724

³ Dubois, J.-L. Dubois—MMAtwo Workshop—PMMA Depolymerization: Scale-up and Industrial Implementation. In Proceedings of the MMAtwo Virtual Workshop on Polymer Recycling, Virtual, 15 September 2020; European Union: Brussels, Belgium, 2020.

⁴ Precedence Research. Polymethyl Methacrylate (PMMA) Market (By Form: Extruded sheet, Cast acrylic sheet, Pellets, Beads, Others; By Grade: General purpose grade, Optical grade; By End-use Industry: Signs & displays, Construction, Automotive, Lighting Fixtures, Electronics, Marine, Healthcare, Agriculture, Consumer Goods, Others) - Global Industry Analysis, Size, Share, Growth, Trends, Regional Outlook, and Forecast 2023-2032. https://www.precedenceresearch.com/polymethyl-methacrylate-market

⁵ PMMA chemical recycling reactor technologies. Polymer Circularity Roadmap: Recycling of Poly(methyl methacrylate) as a Case Study. Edited by D. D’hooge, Y. Marien, J.-L. Dubois. 2022 (65-86)

⁶ Market Research Reports. Methyl Methacrylate (MMA) Market Report By Application (Chemical Intermediates, Surface Coatings, Emulsion Polymer), By Grade (General Grade MMA, Optical Grade MMA, Industrial Grade MMA), By End-Use Industry (Construction, Automotive, Electronics, Medical, Packaging, Aerospace, Others), By Region and Companies - Industry Segment Outlook, Market Assessment, Competition Scenario, Trends and Forecast 2024-2033. https://marketresearch.biz/report/methyl-methacrylate-mma-market/.