Over the years, plastic waste processing has quickly become a major environmental issue. Only 10% of the total plastic used is currently being recycled, while the rest is either incinerated or landfilled. The economic unfeasibility of recycling mixed waste plastic further adds on to this glaring problem.

Interface Polymers, a startup based out of the UK, are tackling this issue with a unique solution. Their product facilitates recycling of immiscible plastic, imparting value to old plastic in the process. In our conversation with the Interface Polymers team, we gained a comprehensive overview of POLARFIN^®, the additive which enables recycling of old mixed plastic streams.

In this article, Ross Baglin, Christopher Kay, Simon Waddington and Tim Clayfield share their valuable insights about the problem and their clever solution.

Versatility at its peak

“We are a product-focused company. What we have invented and developed is a diblock copolymer which is made up of a polyolefin (either PE or PP)  at one end, and a polar polymer at the other end,” began Tim

The additive copolymer, when added to dissimilar polyolefin molecules, connects the plastics and creates new blends that can be recycled. “We like to compare it to soap: what soap does to emulsify grease and water by connecting polar water and non-polar oils, we can do for polymers that reject each other. By fine-tuning the polar head of our di-block, we can create a world of connectedness between plastics, and join various polymers in ways that were not previously possible,” continues Tim.

Recycling (especially the intractable problem of recycling multilayer film) is one of the several capability pillars of POLARFIN^® diblocks. The use of molecular polarity with polyolefins has many uses: in compatibilising mixed plastics; in making plastic surfaces accept paint, glue and anti-fogs (eg in greenhouses) ; and in dispersing materials within polyolefin matrices.  

Three primary pillars

POLARFIN^® diblocks are very efficient in compatibilising mixed waste streams. The additive has 3 main pillars of functionality.

 a)     Connecting dissimilar plastic:    This is the pillar that supports recycling of mixed plastic waste and can make a major contribution in solving the world’s problem with plastic waste material while reducing raw material costs. Furthermore, it not only recycles mixed plastic waste but also creates blends (or alloys), with better performance parameters (eg. stronger, lighter) than the original material. 

b)     Connecting surfaces:  Polarfin^® moleculesplant their non-polar “block” in PE or PP surfaces, and leave a polar block at the surface. In this way, Polarfin can make paints, glues and greenhouse/packaging anti-fogs adhere “stronger for longer” to polyolefin surfaces with none of the pre-treatments typically required today.

c)      Dispersing materials in plastic matrices: Today, many materials have to be evenly embedded in plastics : from thermoplastic elastomers in car parts to increase resilience, to glass fibres in the resins that make fiberglass and mineral fillers that stop polymer cabling from catching fire.  A major problem in industry is achieving adequate dispersion of these fillers in the polyolefin mould. Polarfin’s^® electrostatic properties can optimize this dispersion, leading to enhanced scratch resistance, fire resistance, impact toughness and more.

Although different, the pillars have a common characteristic. Irrespective of the application, it connects polar and non-polar molecules in plastics.   And chemically, it all relies on the ability to connect two molecular blocks via a bridge molecule. Ross describes this as “like a hose coupling :  adding this hose-coupling to a Polyolefin tail (either PE or PP) is standard for all applications.  Its only the polar head that latches onto the coupling, that we fine-tune based on the required application.” explains Ross.

Making plastic waste valuable

How is POLARFIN^® directly contributing to making plastic waste stream circular?

“In order to understand how plastic recycling is facilitated by POLARFIN^®, we can take an example of polyethylene (PE) and polyamide (PA) -based film used to pack meat or cheese. The film maintains optimum storage conditions for the products.   At the end of its life, it cannot be recycled : a blend is left behind with large clumps of PA in the PE. This is essentially rubbish.

If you mix just 1% of POLARFIN^®, the PA particles get dispersed all over the PE and stick tightly to the surface which can be further recycled into films.” Tim explained.

The new recycled blend makes films that are even stronger and with better physical properties, than the ones in the original packaging.  After Polarfin^® has been added, the bonds between the PA and PE are stronger than the PE was originally, so they strengthen the resulting film, which is also free of gels and flow-marks.

Steps towards circularity

The Interface Polymers team have defined a 3-phase approach to realize their goal of achieving circularity in the plastic waste stream.

The first phase focuses on post-industrial recycling. According to their research, every year, 10% of packaging gets wasted even before it is ever used. This is about 200 kT (in Europe) of plastic which isn’t accepted by end customer due to faults, wrinkles, or quality issues. This plastic is simply incinerated or sent to landfills.  IPL are now collaborating with packaging companies to recycle this plastic and put it back into the value chain, and this will step up when a pilot plant comes online late this year.

The second phase would focus on making films “recycle-ready”. This means that packaging films would be manufactured with POLARFIN^® already in it. This would make recycling films at the end of life easy and without the need for extra additives.  This is a concept that IPL have already demonstrated at factory scale with a collaborative partner in the film industry.

The third phase would target the post-consumer recycling market. Active collection schemes for old plastic would create value for consumers and brand owners across many different segments.  “We are literally creating a valuable product out of rubbish – turning film waste which used to become ash, back into film.” said Tim. 

“POLARFIN^®’s greatest value stems out of its efficiency. A kilogram of the additive saves over a hundred times its own weight in carbon dioxide compared to incinerating the waste. It facilitates customers to supply carbon zero products. This carbon credit opportunity, plus the increasing prevalence of single-use plastic taxes across the world makes this an imperative for multi-layer film-makers” said Tim.

Diversity of applications

The versatility of POLARFIN^® makes it quite suitable for applications in various industries. An example is in the automotive industry.

“More and more auto manufacturers are adopting polypropylene as the thermoplastic material of choice. In order to be market-ready, high-quality paints and coatings are required on the various panels and external parts of vehicles. POLARFIN^® is sprayed onto the panels as a primer before applying the coat of paint. This results in an extremely durable coat of paint that doesn’t come off, because it is so molecularly bound to the surface,” explained Ross.

The diverse range of potential applications can be seen in the diagram below.

In essence

POLARFIN^® is a versatile new additive with the capability of imparting various value adding properties such as superior material adhesion, chemical resistance, anti-fogging, and improved recyclability of plastics.

Interface Polymers is well positioned to scale up plastic recycling via a pilot plant under development with a capacity of 10 MT per year.  They are well-equipped to tackle the rising environmental problem associated with plastic pollution and make “impossible” plastics truly circular.