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Adrian Wilson

Editor's Viewpoint

2nd August 2019, UK

Where next for bioplastics and biocomposites?

ORNL is a leader in additive manufacturing and large-scale printing. © ORNL

ORNL is a leader in additive manufacturing and large-scale printing. © ORNL

Bioplastics are top of the list in a new World Economic Forum (WEF) report, Top 10 Emerging Technologies 2019, above social robots, tiny lenses for miniature devices, disordered proteins as drug targets, smarter fertilizers, collaborative telepresence, advanced food tracking and packaging, safer nuclear reactors, DNA data storage and the utility-scale storage of renewable energy.

The need for bio-based alternatives to our current plastics appears pretty obvious, with an annual 400 million tons currently produced – a figure that is expected to triple by 2050 without a global change in direction – and only 15% of it is recycled.

Options

The resistance of conventional plastics to microbial digestion and the problems they have been causing in the oceans have been well chronicled, but the bioplastic options currently available – mostly made from corn, sugar cane or waste fats and oils – generally lack the necessary mechanical strength and visual characteristics for replacements of anything above basic packaging.

Indeed, European Bioplastics reports that global bioplastics production capacity is set to increase from around 2.1 million tons in 2018 to 2.6 million tons in 2023, which could be viewed as positive growth for an established market, but not for one at the top of the list of what the WEF views the most urgent priority in establishing a circular economy.

PLAs (polylactic acids) and PHAs are driving this growth.  PHAs have been in development for a while and are now entering the market at a larger commercial scale, with production capacities set to quadruple in the next five years. These polyesters are bio-based and biodegradable and feature a wide array of physical and mechanical properties.

Loop’s process allows plastics currently of no or little value to be diverted, recovered and recycled endlessly. © Loop

Loop’s process allows plastics currently of no or little value to be diverted, recovered and recycled endlessly. © Loop

Production capacities of PLA are meanwhile set to double by 2023.  PLA is a very versatile material that features excellent barrier properties. High-performance PLA grades can be an ideal replacement for several conventional fossil-based plastics such as polystyrene and polypropylene.

Bio-based, non-biodegradable plastics, including the drop-in solutions bio-based PE (polyethylene), PET (polyethylene terephthalate) and PA (polyamide), currently make up around 50% or one million tons of the global bioplastics production capacity. The production of bio-based PE is predicted to grow as new capacities come on line in Europe, but plans to increase production capacities for bio-based PET have not been realised at the previously-anticipated rate.

Transformational

What will have a significant impact are some potentially transformational technologies being developed , initially or the packaging industry, such as the patented zero energy depolymerization process developed by Canadian start-up Loop Industries.

Loop’s process allows plastics of no or little value – plastic bottles,  packaging and polyester textiles of any colour, transparency or condition, and even plastics retrieved from the oceans that have been degraded by sun and salt  – to be diverted, recovered and recycled endlessly into new, virgin-quality PET that even meets FDA requirements for use in food-grade products.

Coca Cola Danone, Evian, L’Oreal and Pepsico are among the major brands who have quickly signed agreements with Loop, which has commercial production plants scheduled.

Ioniqa, is meanwhile building its first 10-000-ton PET plastic upcycling factory in Geleen, The Netherlands, for converting PET waste into high-grade, pure PET raw material, initially for food packaging, having a further partnership with Unilever.

A clean-tech spinoff from the Eindhoven University of Technology, Ioniqa’s cost effective process exploits smart fluids and a unique separation process to recover virgin material, with which new high-end PET can be manufactured via polymerization.

Cellulose

Recent breakthroughs in producing plastics from cellulose or lignin (the dry matter in plants) meanwhile promise to overcome the drawbacks of current bioplastics, the WEF believes.

Cellulose, the most abundant organic polymer on earth, is a major component of plant cell walls and lignin fills the spaces in those walls, providing strength and rigidity. To make plastics from these substances, manufacturers must first break them into their building blocks, or monomers.

Investigators have recently found ways to do so for both substances. The lignin work is particularly important, the WEF believes, because lignin’s monomers are composed of aromatic rings – the chemical structures that give some standard plastics their mechanical strength and other desirable features. Lignin does not dissolve in most solvents, but investigators have shown that certain environmentally friendly ionic liquids (which are composed largely of ions) can selectively separate it from wood and woody plants. Genetically engineered enzymes similar to those in fungi and bacteria can then break the dissolved lignin into its components.

The development of cellulose nanofibres (CNFs), which have extraordinary properties, is currently intense, particularly in Japan.

Biocomposites

In the composites area, there has been much work on the development of natural fibre reinforcements, and there is an emerging interest in bioresins, although many of the current solutions only contain a fraction of biosourced material within an otherwise synthetic material matrix.

Industry analyst IDTechX observes that the main commercial applications for these materials have so far been in the automotive sector and in sports equipment.

The automotive sector already makes good use of short bast fibres for the interior of car doors to provide lightweight sound and vibration dampening. EcoTechnilin, a Cap Seine company, is the market leader for such short flax fibre products and its Flaxpreg, developed with Faurecia, is also employed in vehicle trunk floors, demonstrating that biocomposites can be used for structurally significant parts.

Strong growth is anticipated for such products in the coming years, but it pales into insignificance when compared to, for example, the huge investments that are currently being made in the carbon composites supply chain.

3D printing and CNFs

A new US$ 20 million research collaboration between Oak Ridge National Laboratory (ORNL) and the University of Maine (UMaine), however, is now launching the first large-scale bio-based additive manufacturing programme in the USA, with a focus in particular, on also exploiting the properties of CNFs.

Scientists from ORNL and UMaine will conduct fundamental research in several key areas, including CNF production, drying, functionalisation, and compounding with thermoplastics, multiscale modelling and sustainability life-cycle analysis.

By placing CNFs into plastics, strong, stiff and recyclable bioderived material systems can be developed that can be 3D printed at deposition rates of hundreds of kilos per hour and up to 50% cellulose fibre loading.

Printing with 50% wood could open significant new markets for pulp, fibres and forest products industries and as a forest product, it is believed CNFs could rival steel for performance properties.

ORNL is a leader in additive manufacturing and large-scale printing and in 2015 attracted considerable attention for 3D printing a replica of the Shelbey Cobra sports car.

In addition, it has 3D printed boat moulds, wind turbine blades, trim-and-die-tools for aerospace and moulds for precast concrete used in building applications. ORNL scientists are also leaders in 3D printing with renewable feedstocks and multi-materials such as lignin, bamboo, polymers and metals.

The ORNL and UMaine research teams will now work with the forest products industry to produce new bio-based materials that will be conducive to 3D printing large-scale products composite parts.

In 2019, the bioplastics and biocomposites industries appear highly fragmented and perhaps lacking the overall momentum required for them to gain mass market traction.

In combination with the latest manufacturing technologies, however, advances such as those being pioneered by Loop and Ioniqa for the packaging fields, as well as developments in cellulose and lignin, will certainly contribute to speeding things along.

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