What if glass fiber reinforced polymer (GFRP) composites could be composted at the end of their useful life, in addition to the decades of proven benefits of weight reduction, strength and stiffness, corrosion resistance and durability? That, in a nutshell, is the appeal of ABM Composite’s technology.
Bioactive glass, high strength fibers
Founded in 2014, Arctic Biomaterials Oy (Tampere, Finland) has developed a biodegradable glass fiber made from so-called bioactive glass, which Ari Rosling, R&D director at ABM Composite, describes as “a special formulation developed in the 1960s that allows glass to be degrade under physiological conditions. When introduced into the body, the glass breaks down into its constituent mineral salts, releasing sodium, magnesium, phosphates, etc., thus creating a condition that stimulates bone growth.”
“It has similar properties to alkali-free glass fiber (E-glass).” Rosling said, “But this bioactive glass is difficult to manufacture and draw into fibers, and until now it has only been used as a powder or putty. As far as we know, ABM Composite was the first company to make high-strength glass fibers from it on an industrial scale, and we are now using these ArcBiox X4/5 glass fibers to reinforce various types of plastics, including biodegradable polymers”.
Medical implants
The Tampere region, two hours north of Helsinki, Finland, has been a centre for bio-based biodegradable polymers for medical applications since the 1980′s. Rosling describes, “One of the first commercially available implants made with these materials was produced in Tampere, and that’s how ABM Composite got its start! which is now our medical business unit”.
“There are many biodegradable, bioabsorbable polymers for implants.” He continues, “but their mechanical properties are far from natural bone. We were able to enhance these biodegradable polymers in order to give the implant the same strength as natural bone”. Rosling noted that medical grade ArcBiox glass fibers with the addition of ABM can improve the mechanical properties of biodegradable PLLA polymers by 200% to 500%.
As a result, ABM Composite’s implants offer higher performance than implants made with unreinforced polymers, while also being bioabsorbable and promoting bone formation and growth. ABM Composite also uses automated fibre/strand placement techniques to ensure optimal fibre orientation, including laying fibers along the entire length of the implant, as well as placing additional fibers at potentially weak spots.
Household and technical applications
With its growing medical business unit, ABM Composite recognises that bio-based and biodegradable polymers can also be used for kitchenware, cutlery and other household items. “These biodegradable polymers typically have poor mechanical properties compared to petroleum-based plastics.” Rosling said, “But we can reinforce these materials with our biodegradable glass fibers, making them virtually a good alternative to fossil-based commercial plastics for a wide range of technical applications”.
As a result, ABM Composite has increased its technical business unit, which now employs 60 people. “We offer more sustainable end-of-life (EOL) solutions.” Rosling says, “Our value proposition is to put these biodegradable composites into industrial composting operations where they turn into soil.” Traditional E-glass is inert and will not degrade in these composting facilities.
ArcBiox Fibre Composites
ABM Composite has developed various forms of ArcBiox X4/5 glass fibers for composite applications, from short-cut fibers and injection moulding compounds to continuous fibers for processes such as textile and pultrusion moulding. The ArcBiox BSGF range combines biodegradable glass fibers with bio-based polyester resins and is available in general technology grades and ArcBiox 5 grades approved for use in food contact applications.
ABM Composite has also investigated a variety of biodegradable and bio-based polymers including Polylactic Acid (PLA), PLLA and Polybutylene Succinate (PBS). The diagram below shows how X4/5 glass fibres can improve performance to compete with standard glass fibre reinforced polymers such as polypropylene (PP) and even polyamide 6 (PA6).
ABM Composite has also investigated a variety of biodegradable and bio-based polymers, including Polylactic Acid (PLA), PLLA and Polybutylene Succinate (PBS). The diagram below shows how X4/5 glass fibers can improve performance to compete with standard glass fibre reinforced polymers such as polypropylene (PP) and even polyamide 6 (PA6).
Durability & Compostability
If these composites are biodegradable, how long will they last? “Our X4/5 glass fibers don’t dissolve in five minutes or overnight like sugar does, and while their properties will degrade over time, it won’t be as noticeable.” Says Rosling, “To degrade effectively, we need elevated temperatures and humidity over long periods of time, as found in vivo or in industrial compost piles. For example, we tested cups and bowls made from our ArcBiox BSGF material, and they could withstand up to 200 dishwashing cycles without losing functionality. There is some degradation of the mechanical properties, but not to the point where the cups are unsafe to use”.
However, it is important that when these composites are disposed of at the end of their useful life, they do meet the standard requirements needed for composting, and ABM Composite has carried out a series of tests to prove that it meets these standards. “According to the ISO standards (for industrial composting), biodegradation should occur within 6 months and decomposition within 3 months/90 days”. Rosling says, “Decomposition means placing the test sample/product into the biomass or compost. after 90 days, the technician examines the biomass using a sieve. after 12 weeks, at least 90 per cent of the product should be able to pass through a 2 mm × 2 mm sieve”.
Biodegradation is determined by grinding the virgin material into a powder and measuring the total amount of CO2 released after 90 days. This assesses how much of the carbon content of the composting process is converted into water, biomass and CO2. “To pass the industrial composting test, 90 per cent of the theoretical 100 per cent CO2 from the composting process must be achieved (based on carbon content)”.
Rosling says ABM Composite has met the decomposition and biodegradation requirements, and tests have shown that the addition of its X4 glass fibre actually improves biodegradability (see table above), which is only 78% for an unreinforced PLA blend, for example. He explains, ”However, when our 30% biodegradable glass fibers were added, biodegradation increased to 94%, while the degradation rates remained good”.
As a result, ABM Composite has demonstrated that its materials can be certified as compostable according to EN 13432. Tests that its materials have passed to date include ISO 14855-1 for the final aerobic biodegradability of materials under controlled composting conditions, ISO 16929 for aerobic controlled decomposition, ISO DIN EN 13432 for chemical requirements, and OECD 208 for phytotoxicity testing, ISO DIN EN 13432.
CO2 released during composting
During composting, CO2 is indeed released, but some remains in the soil and is then utilised by plants. Composting has been studied for decades, both as an industrial process and as a post-composting process that releases less CO2 than other waste disposal alternatives, and composting is still considered an environmentally friendly and carbon footprint reducing process.
Ecotoxicity involves testing the biomass produced during the composting process and the plants grown with this biomass. “This is to make sure that composting these products does not harm the growing plants.” Rosling said. In addition, ABM Composite has demonstrated that its materials meet the biodegradation requirements under home composting conditions, which also require 90% biodegradation, but over a 12-month period, compared to a shorter period for industrial composting.
Industrial applications, production, costs and future growth
ABM Composite’s materials are used in a number of commercial applications, but more cannot be revealed due to confidentiality agreements. “We order our materials to suit applications such as cups, saucers, plates, cutlery and food storage containers,” Rosling says, “but they are also used as an alternative to petroleum-based plastics in cosmetic containers and large household items. More recently, our materials have been selected for use in the manufacture of components in large industrial machinery installations that need to be replaced every 2-12 weeks. These companies have recognised that by using our X4 glass fibre reinforcement, these mechanical parts can be made with the required wear resistance and are also compostable after use. This is an attractive solution for the near future as these companies face the challenge of meeting new environmental and CO2 emission regulations”.
Rosling added, “There is also growing interest in using our continuous fibers in different types of fabrics and nonwovens to make structural components for the construction industry. We are also seeing interest in using our biodegradable fibers with bio-based but non-biodegradable PA or PP and inert thermoset materials”.
At present, X4/5 fiberglass is more expensive than E-glass, but production volumes are also relatively small, and ABM Composite is pursuing a number of opportunities to expand applications and facilitate a ramp-up to 20,000 tonnes/year as demand grows, which could also help to reduce costs. Even so, Rosling says that in many cases the costs associated with meeting sustainability and new regulatory requirements have not been fully considered. Meanwhile, the urgency of saving the planet is growing. “Society is already pushing for more bio-based products.” He explains, “There are a lot of incentives to push recycling technologies forward, the world needs to move faster on this and I think society will only increase its push for bio-based products in the future”.
LCA and Sustainability Advantage
Rosling says ABM Composite’s materials reduce greenhouse gas emissions and use of non-renewable energy by 50-60 per cent per kilogram. “We use the Environmental Footprint Database 2.0, the accredited GaBi dataset, and LCA (Life Cycle Analysis) calculations for our products based on the methodology outlined in ISO 14040 and ISO 14044″.
“Currently, when composites reach the end of their life cycle, a lot of energy is required to incinerate or pyrolyse composite waste and EOL products, and shredding and composting is an attractive option, and it’s definitely one of the key value propositions we offer, and we’re providing a new type of recyclability.” Rosling says, “Our fiberglass is made from natural mineral components that are already present in the soil. So why not compost EOL composite components, or dissolve fibers from non-degradable composites after incineration and use them as fertiliser? This is a recycling option of real global interest”.
Post time: May-27-2024