From Feedstocks to Functionality, Challenging Conventional Ideas About PLA

Bioplastics have gained attention in recent years due to their potential to reduce greenhouse gas emissions and, for certain types of bioplastics, the ability to create compostable products, but functionality and cost effectiveness are critical to ensuring they can be used more widely to create sustainable solutions. At SustPack, Marc Verbruggen, president and CEO of NatureWorks, gave a fascinating update on some of the latest developments in the PLA industry.

Bioplastics such as PLA can be made from a wide variety of feedstocks, ranging from crops such as corn and sugarcane, to cellulosic materials such as wood chips or bagasse.   Sustainability of a bioplastic — as well as the cost —depends both on the feedstock used and the efficiency of the conversion of the sugar in the feedstock to the polymer. PLA performs well relative to other bioplastics in conversion efficiency, but there is a great deal of regional variability.  While use of cellulosic feedstocks to create second-generation bioplastics represents a newer technology, the sustainability of each feedstock must be evaluated on its own merit. For example, in Nebraska, where NatureWorks has a PLA factory, corn is readily available and may be a more sustainable feedstock, whereas in Finland, a locally-sourced cellulosic material such as woodchips may be a better choice – at least given current commercially viable technology.

While plants such as corn, sugarcane, or trees are effective at converting carbon dioxide to carbohydrates, Verbruggen suggested that they may not actually be the most efficient option.  The newest technology under development involves the use of methanotropic bacteria and cyanobacteria to create lactic acid directly from methane or carbon dioxide. The resulting lactic acid can then be used to produce PLA. Although this technology is still a few years from commercialization, the prospect of a more efficient third-generation bioplastic feedstock with the potential for lower environmental impact is exciting news.

Innovative feedstocks are great, but ultimately, to gain market share the resulting plastic will need to provide functionality in creative new applications. During his session, Verbruggen shared some new potential applications for PLA. PLA can be used in a sealant web to create a product that is bio-based and compostable, and can also be lighter than a comparable polyethylene product, making it more cost competitive. In addition, PLA-based cups for dairy products such as yogurt can perform better than high impact polystyrene: they can be less hazy and have lower oxygen permeability, in addition to being compostable. Coffee pods are a third potential use for PLA. While standard PLA has not had the necessary heat resistance for this application, Verbruggen argued that crystalline PLA can stand up to the high temperatures of coffee brewing and can also provide good barrier qualities.  If PLA can be used to create compostable coffee pods, it could be a great opportunity to help get coffee grounds to the composters who find them valuable in compost piles.

It is exciting to hear about the potential for new innovations in this space, ranging from the ability to create feedstocks directly from carbon dioxide and methane using bacteria to new applications where PLA has the potential to provide improved functionality during the use phase relative to traditional plastics, in addition to being sustainably sourced and compostable.

For more insight into the bioplastics industry, join us at SPC Bioplastics Converge on May 31-June 1, 2017 in Washington, D.C.

Related Posts