Bioplastics are emerging as viable alternatives to petroleum-based polymers. This quiet revolution goes well beyond the standard drivers for sustainably sourced and/or compostable materials. I attended the 2013 BioPlastek conference in San Francisco this June and was inspired by the progress. The ability to capture carbon and create materials through sustainable manufacturing pathways provides a glimmer of hope in our ability to build a regenerative economy.
To illustrate this progress, I have outlined six key areas to watch in bioplastic development and identified key drivers for new bioplastic recovery strategies.
1. New sourcing options for plant-based raw materials
Sources for plant-based raw materials can come from traditional crops like corn and sugarcane, but are increasingly being derived from non-food sources. Cellulosic sugars can be derived from inexpensive feedstocks like agricultural waste, forest waste, and municipal waste. Cheap DNA sequencing technology has enabled the identification of biomass deconstruction genes that have led to patentable enzymes to extract cellulosic sugars from these alternative feedstocks. Technologies have emerged to concentrate the sugars from these feedstocks locally before shipping for additional processing. These technologies are enabling significant cost reductions in bringing these new feedstock opportunities to market. Once extracted and concentrated, these non-food carbon sugars can be converted to C5 and C6 carbon monomers. These biomonomers are suited to produce higher value plastics versus fuels. One company, Micromidas (www.micromidas.com), is producing p-Xylene from post-consumer corrugated containers.
2. Drop-in biopolymers and chemical intermediates
We have already seen simple drop-in polymers like ethylene made from sugar cane. Watch for new chemicals and intermediates that take advantage of biological pathways and sugars to create C4 and C6 carbon intermediates and drop-in chemicals from new feedstock sources. Targets include MEG (mono-ethylene glycol) and PTA (purified terephthalic acid) for PET, and adipic acid and HMD for Nylon-6,6.
Investment in shale gas extraction has significantly increased ethylene supply. This increased reliance on shale gas has resulted in a scarcity of some of the traditional by-products from naphtha cracking, such as polypropylene. Drop-in biomonomers and intermediates can help bridge the supply gap.
3. New polymers, new functionality
Avantium (www.avantium.com) is working on combining biobased FDCA (furan-dicarboxylic acid) with biobased MEG to create a new polymer, PEF (polyethylene furanoate). This new biobased material is reported to have a 10x oxygen barrier improvement, a 3x carbon dioxide barrier improvement, a 2x water barrier and an increase in thermal performance of 12 deg Celsius over PET.
Current biopolymers like PLA (polylactic acid) are also being improved. Heat resistance can be improved in PLA through the selection of specific isomers.
4. Hybrid polymers, improved functionality
New functionality is being created based on blends of biopolymers with traditional fossil fuel polymers. Advances have been made in performance fabrics and flexible material blends. This is driven by a desire for converters to create films with new unique properties and create proprietary blends of functional films.
One example of this is the combination of algae with traditional polymers to create a hybrid polymer. Algae contain natural proteins and carbohydrate-based polymers that can be blended with additives to create a new polymeric material. Algae can be harvested from waste water treatment facilities and fish farms. It is a non-food feedstock that can reduce dependence of fossil fuels.
5. Climate mitigation through carbon and methane production technologies
Capturing atmospheric carbon and methane presents an exciting climate mitigation strategy for the bioplastic industry. Newlight Technologies (www.newlight.com) is creating PHA (polyhydroxyalkanoate) from air carbon. A recent breakthrough increasing the efficiency of the reaction has significantly reduced the cost of converting carbon captured from the air into PHA. Methane can also be used as a feedstock to make plastics, alcohols and olefins. Burning methane ignores this huge opportunity to turn it into value-added chemical commodities.
6. Recovery strategy drivers
Biopolymer recovery strategies will continue to shift away from composting and towards collection and re-use. A number of emerging drivers reinforce this.
For example, the China Green Fence (a campaign that bans foreign soiled and unsorted recyclables) will force North Americans to learn how to separate our materials and create new local reprocessing markets. This will open the door for the collection and sortation of new bio-based materials. To aid this process, marker technologies will emerge to help with sortation and recovery of new and existing materials. The ASTM Resin Identification Codes will be expanded to include many new materials. Biopolymers need to be included in this expansion.
In addition, food waste and fiberboard can be used as feedstock for biopolymers. The digesters may be able to reprocess recycled biopolymers by adding them as additional feedstock for new biopolymer materials.
In conclusion, we in the packaging industry tend to think of polymers in terms of finished materials. As we continue to explore biopolymer opportunities, we need to expand our thinking to include chemical intermediates used to make the final polymers and intermediates used in many products and processes. Biological routes of manufacture offer huge opportunities to use renewable plant based waste materials, capture carbon, create new markets for materials and develop a transformative path to a sustainable future.