September 16, 2015
Whatever happened to those "Great Green Plastic Alternatives"?
By Eric Hartman, Product Ventures Vice President Technologies & Commercialization
Just the other day I was reading an article that was a followup to something that had been published a few years ago about promising "green" polymeric materials that were set to take industry by storm. Materials like foamed rPET, algae and PP blends, alge and PS blends, DPET, PHA, PHB, and PLA all showed some promise as potential materials that could be the "next best thing since sliced bread" for industry to pursue as viable replacements to those "bad" fossil fuel derived polymers that had flooded the market.
Now don't get me wrong! I am a firm believer that we should and must find viable replacements for the fossil fuel derived polymers and that we have come to rely on for so many modern conveniences and purposes in our society. Unfortunately the development of viable alternatives takes time.
We need to remember that while the mainstream polymers that we use today like PET , PE and PP were discovered some time ago, (1941, 1935 and 1954 respectively), it took some time for them to be scaled up and become viable candidates to be used for the development of the products we see them in today. These polymers have had well over half a century to become industrialized and widely used.
Green or biopolymers on the other hand are still in their infancy. While there are some biopolymers that do currently exist, those that could be drop in replacements for the likes of PET, PE or PP have yet to be invented or are "developmental" from an industrialization perspective. We need to give them time to be developed and become industrialized and we also need to remember that until they reach scale they will most likely be more expensive than the materials that they are targeted to replace. Which brings up back to the materials I mentioned to begin with, foamed rPet, algae and PP blends, algae and PS blends, DPET, PHA, PHB, and PLA.
Of the 7 materials listed above only one is currently experiencing some commercial success, PLA. Unfortunately, the properties of PLA don't make it a good direct replacement for PET so efforts have focused on either finding alternative applications, which have been limited to date, or, more importantly, finding ways to actually modify the polymer to make it more of a viable substitute for PET in a number of applications. Unfortunately one of the issues with direct substitutions of PLA for PET has to do with the end of life scenario of the component that is manufactured with the polymer. Both PET and PLA are recyclable although a recycling infrastructure for PLA does not yet exist. That means that PLA gets mixed in with PET in the recycling stream, and can potentially contaminate PET that would otherwise go on to rPET applications. Until a viable, cost effective means is developed to separate PET and PLA, and the properties of PLA are further improved it seems like the applications for the polymer will continue to be limited.
Foamed rPET was not really a new material, per se, but a method of producing a useful by product eliminating chemical blowing agents from a foaming process. The material produced by this new "air" based process was useful and one the verge of finding it's way into numerous commercial applications. Unfortunately the company could not come up with a viable business proposition to continue to exist. That said, in my mind this is an instance where the "green" material itself is something that was found to be useful and with the right business infrastructure behind it could once again be on the market.
Using algae as a filler in polymers in place of alternatives seems like a great idea. The algae is an industrial waste product and could make a viable filler in a number of applications. Unfortunately it has a few problems, odor and economics, both of which I feel could be overcome by time, infrastructure and processing developments. Unfortunately until the economics turn around I expect that we will see little from this material.
DPET, or "Direct PET" is a more efficient way of producing PET rather than being a different material. To me this is a no brainer, although it does require scale of applications to make the ecomomics of developing the infrastructure work. My guess is that we will see this material continue to grow and eventually expand widely into the market replacing lower cost materials like PVC and OPS in applications as soon as the economics of scale dictate.
PHA and PHB have not really made any significant inroads into the market as of yet. You hear almost nothing about PHB these days and the primary company that was developing and marketing PHA, Metabolix, is focusing on it's use more as an additive or specialty material. Again, because of scale and a lack of the material being able to be a direct replacement for one of the conventional commodity polymers, I'm not certain that we will ever see these materials be widely used on an industrial basis.
So where does that leave us? Well, we still need time to develop viable alternatives to the current commodity polymers based on biological sources, but like I said at the beginning of this article, the commodity petrochemical based polymers have been around for a while. Yet the development of viable biobased alternatives is still in it's infancy. Catch up with me in another 50 years and we'll see what things look like then. I'd be willing to bet that we will be using a lot more biobased polymers, on an industrial basis than we are today. After all, our petrochemical reserves won't last forever ......
Eric Hartman is the Vice President Technologies & Commercialization for Product Ventures.
Contact Eric at 203.319.1119 or firstname.lastname@example.org.