April 13, 2026
Recycling Thermoplastics: What is Actually Possible?
Contributed by Josh Goldberg, Technical Market and Business Analyst
Single-use plastics like bags, bottles, and takeout containers are usually recycled at a local level by consumers at home through their municipal waste management. What happens to industrial products like pipes? Pipes for residential, industrial, and infrastructure applications can be made from a wide variety of materials, including PVC/CPVC, HDPE, polypropylene (PP), PEX, and fluoropolymers such as PVDF, ECTFE, PTFE, PFA, and FEP. How are all of these different materials repurposed to contribute to a circular economy?
First, what is a “circular economy,” and how does recycling fit into it? In the broadest sense, a circular economy is one in which products are recycled, reused, or regenerated into “new” material. In the world of plastics, ideally, these materials are either mechanically or chemically processed into pellets that can then be extruded into new material. So, what do mechanical recycling and chemical recycling look like?
In general, mechanical recycling involves a few steps. The first step is to sort the materials so you are dealing with a single type of plastic. Next, the material is shredded or ground into smaller particles. After shredding, the plastic undergoes a cleaning process to remove any dirt or debris. It can also go through a second sorting and cleaning process, depending on the individual recycler. Finally, it is melted and pelletized so that it can be extruded into new products. Generally speaking, some quality can be lost during this process due to the potential mixing of different grades of plastic, especially if the plastic has been recycled multiple times.
Chemical recycling can be done in a couple of different ways, depending on the end use of the recycled material. The first way to chemically recycle plastics like HDPE, PP, and even PEX is by a process called pyrolysis. Polyolefins, such as the aforementioned materials, can be heated to around 500 °C in an oxygen-free atmosphere, where the long polymer chains begin to break down, forming several useful products. The primary product this process aims to produce is pyrolysis oil (also known as “pyoil”). Pyoil has several uses, such as serving as a precursor for making new HDPE or PP, or for manufacturing new chemicals, waxes, or lubricants. Pyrolysis can also produce low-molecular-weight gases and miscellaneous solids that can be used as feedstock to power the process itself. Plastics like PVC/CPVC cannot undergo this type of recycling because they can release toxic chlorine gases. Generally speaking, pyrolysis is cheaper than simply incinerating the plastics because the resulting products can be sold to make new material and power the pyrolysis process.
The second type of chemical recycling is called solvent recycling. For this type of recycling, a solvent is carefully chosen to dissolve the plastic without dissolving any of the additives. The liquid is then carefully filtered to remove any of these additives, and the plastic is precipitated from the clean solution for use. Sometimes, this process is run a couple of times to produce higher-purity plastic that is close to the original material. The solvent is also filtered and purified for reuse in further chemical recycling. Solvent recycling can be used for all types of plastics except PEX, which is a cross-linked HDPE (a thermoset rather than a thermoplastic), so it will behave slightly differently than its polyolefin thermoplastic “cousins.” In general, this process can reproduce higher-quality, close-to-original plastics.
PVDF is a bit of a special case, and its recycling method is dependent on where the material is sourced. For instance, with pipes and films, PVDF is often processed mechanically to produce like-new material. However, as lithium batteries became more widely used in consumer and automotive products, another method for recycling PVDF from the batteries was needed. As a result, chemical recycling was implemented for battery applications because those processes can selectively dissolve and filter out the plastic, similar to how other chemical processes are used to recycle other parts of the battery.
Fluoropolymers are generally mechanically recycled, with PTFE accounting for almost 50% of this group of recycled plastics. In addition to more common mechanical methods, they can also be broken down into a fine powder using high-energy radiation. Fluoropolymers generally contain little to no additives, so mechanically recycling these materials produces like-new materials. Additionally, these materials can undergo a process similar to pyrolysis and be run through a special calcium hydroxide filter to produce and capture fluorspar. Fluorspar is the base material that all fluoropolymers are made from, and it is a finite material that is becoming increasingly rare. Remaking fluorspar from recycled material helps to alleviate the market demand for virgin material.
Most pipe manufacturers have a program in place that offers to take on plastics for recycling and reuse. For instance, AGRU has a program that recycles old HDPE pipes into HDPE liners for water and mining applications. In total, around 600 million pounds of HDPE are recycled each year into corrugated drainage pipes. These recycled materials must then meet a set of standards — for the corrugated pipes in particular, they must meet the parameters set by the ASTM F2306 and AASHTO M294R codes.
Recycling industrial pipes is a common practice among pipe manufacturers, and there is a drive, especially in the plastics industry, to contribute to a circular economy. In a world increasingly concerned about plastic pollution, it’s encouraging to know that manufacturers are stepping up to work with responsible contractors to design new, cost-effective ways to extend the life of these fully recyclable performance plastics.