The environmental impact of plastic is driving development of bio-based plastics, but these pose their own difficulties

There can be few hotter topics in the materials sector than the use of plastics. For more than 50 years, global production and consumption of plastics have continued to rise. In 2016, the world produced around 335 million tonnes. However, continued support for the introduction of bio-based products continues to gain momentum, suggesting that wider market penetration is around the corner. Market data shared at the 12th European Bioplastics Conference last November indicated: “Global production capacities of bioplastics are expected to grow by 20% in the next five years.”

According to ProBI, 85% of plastics could technically be substituted with bio-based plastics, reducing dependency on those derived from fossil-based resources. Yet, right now bioplastics represents just 1% of the annual plastics production. Making a difference is a joint effort that requires industry stakeholders, manufacturers, suppliers and consumers being better informed and educated about the challenges and having legislative and regulatory frameworks that actively promote sustainable development and supports innovation.

Until recently the focus has been on bio-based PET. However, the scale of adoption has not been as rapid as anticipated. In Europe, the focus is now shifting to the development of PEF (polyethylene furanoate). Expected to enter the market in 2020, this new polymer is said to feature superior barrier and thermal properties, making it comparable to PET and therefore suitable for the packaging of drinks, food and non-food products.

This raises the question for injection moulders of whether they need to invest in new processing equipment? Not necessarily, says Nigel Flowers, UK managing director at Sumitomo (SHI) Demag. “In theory, you can run bioplastics through an injection moulding machine just as you would any other polymer. The main issue lies in how that plastic performs as an end product, which will dictate what applications it can be considered for.”

Drop-in plastics, such as bio-based PE, bio-based PET, or bio-based polyamides typically have the same technical and functional properties as their conventional counterparts. Used in high-demand and durable applications such as electronics, building and construction, automobiles, and consumer goods, they can, in the main, be processed and recycled in the exact same way. However, other innovative bioplastics such as PLA or starch-based plastics desired for food packaging and in agricultural applications, have different properties, such as improved barrier or compostability.

“If the bioplastic materials properties differ from the material it’s intended to replace, it can have an impact on the production costs of the article in question,” notes Flowers. As a result, careful consideration should be given to the selection of the material and products chosen.

Some bioplastics have yet to fully meet the performance requirements needed to lend themselves to more durable goods. That’s not to say it won’t happen. Heat resistance, enhanced moisture barriers, greater rigidity and flexibility and durability are improving.

Automobile companies are making great strides. Bio-based or partially bio-based commodity plastics such as PE or PET are already being used for applications like car dashboards. Currently, packaging is the leading segment, accounting for almost 60% (1.2 million tons) of the total bioplastics market in 2017.

Three major process technology and equipment specialists, Futerro, Sulzer and TechnipFMC, have formed the PLAnet initiative to promote the production of sustainable plastics made of Polylactic Acid (PLA). The collaboration will support manufacturers interested in entering the bioplastic market by delivering integrated PLA technology packages.

PLA is a versatile bio-based, biodegradable polymer that can replace petroleum-based plastics in a range of applications. Many stages are required to convert sugars from crops into lactic acid, lactide and subsequently PLA.

Futerro, a well-established technology provider for lactic acid and lactide production, and Sulzer Chemtech, a specialist in separation and mixing technologies have over 25 years of experience in lactic acid and PLA’s related processes. Together they have further shown their commitment to facilitate the production of bioplastics by establishing a partnership with TechnipFMC, a leading global EPC contractor with experience in technology development and licensing with fast growing activities in bioplastics and green chemicals.

The agreement between the three parties offers to agricultural, chemical and fibre industries, a fully integrated package addressing the whole PLA value chain. In this way, customers can benefit from direct access to state-of-the-art, customisable solutions for all the aspects and stages of PLA production. PLAnet offers the possibility of a “one-stop shop” for customers interested in PLA production by providing a single point of contact and responsibility.

In particular, PLAnet supports the construction of plants of any size, including PLA facilities with a throughput of up to 100,000 tons per year - that permit manufacturers to save both capital expenditures (CAPEX) and operating expenses (OPEX) by providing for integrated and optimised plant section design.

Within the PLAnet partnership, Futerro’s proprietary technology focuses on the production of lactic acid and raw lactide from sugar or, directly, from biomass; Sulzer contributes the process for the purification of lactide and its polymerisation to obtain PLA while TechnipFMC acts as technology integrator to deliver seamless and optimised Front-End Engineering Design (FEED) packages.

Another intriguing bioplastic development comes from Teysha Technologies, which has developed a natural polycarbonate platform that can create fully biodegradable substitutes for existing petroleum-based plastics. The bioplastic, AggiePol, is derived from sustainable feedstocks and can be physically, mechanically and chemically tuned to suit the needs of its intended application. The versatile material could replace the traditional plastic used in the automotive industry and medical equipment.

Teysha’s technology uses a plug-and-play system that takes monomers and co-monomers, the natural building blocks of plastics, to create an eco-friendly alternative to traditional polymers. Instead of using hydrocarbon-based petrochemicals, which are sourced from fossil fuels and generate various pollutants in the manufacturing of the material, Teysha’s platform uses natural products such as starches and agricultural waste products.

By controlling the chemistry, formulation and polymersation conditions, the polycarbonate materials created by Teysha’s technology can be precisely tuned. Unlike existing bioplastics such as PLA and PHA, it is claimed that the degradation rate of Teysha’s AggiePol can also be tuned, minimising the environmental impact of plastic products after the end of their useful lifetime.

“In the sea, existing plastics often break down into microplastic particles that can be consumed by marine life and ultimately work their way up the food chain and end up on our dinner plates,” explained co-inventor and head of research at Teysha Technologies, Dr Ashlee Jahnke. “The ultimate fate of plastic materials and whether they breakdown must be taken in to consideration, as many plastics can persist in the environment or landfills for thousands of years.”

Author
Paul Fanning

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