The Designer’s Compass - Part 4: Beyond the Bin: Carbon Capture and Nature’s Toolkit for Future Materials

Sustainable material selection lacks a clear endpoint because technologies constantly evolve and shift boundaries. Designers must look beyond established material categories to find true innovation in circularity. This emerging frontier includes complex new approaches such as harnessing natural growth processes, utilizing captured atmospheric carbon, and fundamentally rethinking plastic recycling technologies. These novel material strategies define the future of sustainable product development.

The Role of Carbon Capture and Utilization (CCU)

Most people view carbon dioxide (CO2) strictly as atmospheric pollution. This view represents only part of the story, as CO2 is essential for life on Earth. CO2 is a prerequisite for life and serves as a crucial raw material in many natural growth processes, especially plant growth. Carbon Capture and Utilization (CCU) refers to several emerging processes that actively seek to use carbon oxides, like CO and CO2, to convert into fuels, chemicals, or raw materials.

Designers like Teresa van Dongen are mapping materials derived from CCU technologies, illustrating this shift in perspective. CCU technologies can capture carbon directly at the source, preventing large volumes of greenhouse gases from being released into the atmosphere by heavy industry. For example, the US-based company LanzaTech installs CCU technologies at energy-intensive sites such as steel mills. LanzaTech converts the captured carbon into chemicals. These chemicals produce raw materials, such as the EVA foam used in the midsole of On Running’s CleanCloud™ trainer. The upper of the CleanCloud™ shoe uses CCU-based polyester textiles from the French supplier Fairbrics. Fairbrics reports their textiles actively remove carbon from the atmosphere. They also claim the production uses less energy than conventional petrochemical-based polyester.

Sequestering Carbon in Construction

CCU strategies also include approaches that use captured carbon without immediately converting it into new chemicals. Carbstone offers an alternative to conventional concrete developed by the Belgian companies VITO and Orbix. Carbstone uses waste slag from the steel industry as the primary raw material. Captured carbon acts as the hardening agent during the manufacturing process. The amount of carbon sequestered in each cubic meter of Carbstone roughly equals the CO2 emitted during the production of an equal volume of conventional concrete. This process holds huge potential for reversing the massive environmental impact of the concrete industry. It simultaneously reduces waste from the iron and steel industry.

Another CCU approach involves allowing natural carbon capture processes to run their full course. Olivine is an abundant volcanic mineral that naturally absorbs CO2 from the atmosphere. Grinding olivine rocks into sand or gravel exponentially increases its carbon capture capacity due to the much larger surface area. The Netherlands-based supplier GreenSand reports that one tonne of olivine sand absorbs about one tonne of CO2 from the atmosphere. GreenSand has implemented projects using olivine sand, including the gravel bed for a trainline track in the Netherlands. This natural absorption process is slow, taking up to ten years to reach maximum CO2 capacity.

Green Minerals, another Dutch company, developed a reactor process to accelerate CO2 absorption. This controlled process reduces the absorption time to just a few minutes. It results in olivine powder fully charged with CO2. This powder acts as a functional filler used in applications such as coated paper, cement, and plastic materials.

Carbon in Plastics Production

Plastics suppliers are also integrating captured carbon into their feedstocks. Covestro, a German plastics supplier, developed Cardyon®, a polyol partially derived from CO2. Polyols are a fundamental ingredient in soft plastics like polyurethane (PUR) foam and thermoplastic polyurethane (TPU) elastomers. Using CO2 as a raw material in polyols directly replaces petrochemical-based chemicals. The Aireal material library features examples like Cardyon® flexible foam and PUR hard foam produced using this technology.

Natural Growth Processes for Materials

Natural growth processes inspire materials development, resulting in strong and durable structures derived from biology. Mycelium is the fine network of roots that connects fungi. Suppliers learned how to ‘tame’ these structures, growing them into complex parts and components for product design. These grown materials are surprisingly strong, tear-resistant, soft to the touch, and naturally water-repellent. The Vancouver-based brand Well Kept uses mycelium inserts for their razor packaging, replacing conventional plastic foam. Mycelium is actively being explored as an alternative to plastic foam in packaging applications.

SCOBY (symbiotic culture of bacteria and yeast) is another natural growth material derived from bacteria. This jelly-like biofilm is a by-product of fermentation in foods and drinks such as kombucha. When dried, SCOBY becomes a durable, flexible material with properties similar to leather. Designers use SCOBY sheet materials in small volumes for applications like interior accessories and jewelry.

Studying the formation of corals also inspired material innovation. Biomason developed Biocement®, an alternative to conventional Portland cement, by researching the microorganism interactions that form corals. Biocement® grows at ambient temperatures without CO2 emissions. Biomason’s first commercially available products are tiles made from recycled granite using Biocement® as the binder. These tiles are known as Biolith® in the US and BioBasedTiles® in Europe.

The Evolution of Plastic Recycling

The traditional approach to plastic recycling, known as mechanical recycling, faces major hurdles due to complex waste streams. This linear approach requires pure, uncontaminated materials, contrasting sharply with the chaotic nature of consumer waste. Chemical recycling offers new potential for a generation of high-quality recycled materials. Chemical recycling breaks down plastic waste into its core chemical building blocks. These building blocks are then used to make new recycled plastics or other chemicals.

Chemical recycling is capable of producing recycled materials with properties essentially identical to pure, virgin materials. This is because pigments, additives, and other contaminants are separated during the process. This approach also allows recycling a wider range of plastic waste, including different types of plastic mixed together. Chemical recycling processes are currently rather energy-intensive.

There are three key types of chemical recycling.

1. Dissolution removes contaminants, pigments, and additives, turning the plastic waste back into a pure polymer. Dissolution requires plastic waste to be sorted by type. US-based supplier PureCycle reports their proprietary dissolution process reduces CO2e emissions for recycled polypropylene by roughly 35 percent compared to virgin material.
2. Depolymerization removes contaminants and further breaks down plastic waste into monomers. Monomers are refined into recycled polymers, offering greater flexibility. Eastman uses depolymerization of recycled PET waste to produce monomers for their Tritan Renew and Cristal Renew copolyester materials.
3. Conversion breaks plastic waste down into feedstocks. Conversion processes often accept mixed plastic waste. London-based Plastic Energy provides TACOIL™ feedstock from its plants. TACOIL™ produces ethylene and propylene, key ingredients for various plastics. Low-density polyethylene (LDPE) produced with TACOIL™ shows 55 percent lower CO2e emissions than virgin material.

Mechanical Recycling for Mixed Waste

Mechanical recycling traditionally requires careful sorting of different plastic types before processing can begin. Flexible plastic packaging consists of several layers of different materials, often impossible to separate. Omni Polymers, a Swedish recycler, developed a mechanical recycling process for flexible packaging without separation. This process yields a plastic blend consisting primarily of polypropylene (PP) and polyethylene (PE). A pilot plant is operating in Sweden with the capacity to produce 15,000 tonnes of recycled material annually.

Blending recycled material with virgin polymer is another strategy to overcome performance deficits in recycled streams. SABIC developed a polycarbonate material containing 20 percent post-consumer recycled (PCR) PET. This recycled PET is often degraded from environmental exposure to UV radiation and seawater. Blending creates XENOY™, a material with sufficiently high performance for demanding applications like the Microsoft Ocean Plastic mouse.

EcoRub, a Swedish recycler, specializes in thermoplastic elastomers (TPEs), a plastic group that is not widely recycled. EcoRub’s TPRR® (thermoplastic recycled rubber) material blends PCR tire rubber with polypropylene (PP). This blend forms using common thermoplastic processes, such as injection molding and extrusion. This breakthrough makes pure thermoset rubber compatible with thermoplastic applications.

Designing with Mono-materials

Plastic composites offer enhanced properties but are difficult to recycle because they contain blends of different materials. Mono-material plastic composites offer a solution, made entirely from a single material to enhance recyclability. Flexible packaging film requires multiple layers for good sealing properties. New processes create single-plastic films with improved sealing, known as biaxially oriented film. Biaxially oriented polyethylene (BOPE), polypropylene (BOPP), and PET (BOPET) films are available from several suppliers.

Biaxially oriented film strands are oriented in two directions, which prevents oxygen and liquids from passing through. Coffee Collective bags use BOPE film, which recycles without separation with other polyethylene waste.

Rigid plastic parts requiring high strength often use composites mixing a plastic matrix with a reinforcing textile or loose fibers. Recycling these conventional composites shreds the fibers, reducing material strength and performance. Self-reinforced composites are an alternative structure made from a single material. These composites, like the polypropylene-based CURV®, Torodon®, and PURE®, use conventional plastic fiber for reinforcement. These mono-material sheet composites recycle easily with other plastic waste of the same type. The Edelrid SALATHE LITE climbing helmet uses a CURV® self-reinforced polypropylene shell with an expanded polypropylene foam core. This forms a lightweight mono-material assembly that recycles efficiently with other PP waste. The high value of these emerging technologies lies in extending material circulation and keeping plastic waste out of the environment.